Dento Facial

ISS No: 837103940484

2011 Volume 1

Issue No:1

JOURNAL OF DENTOFACIAL SCIENCES AND RESEARCH

Published By Academy of Dental Sciences and Research

J D S R Email: editorjdsr@educareinstitute.in

Web: www.educareinstitute.in

inside

Journal of Dentofacial Sciences and Research

Research articles

7

2011 Volume 1

7

Use of single Ni-Ti instrument for the preparation of canal on a curved resin block A comparative study Krishna Prasad Shetty, Sandeep Rajalbandi, S.V. Satish

Review articles

11 20

Biofilms in endodontics – A review Yadav Chakravarthy

Differential diagnosis of swellings in the floor of the mouth Manjunath N, Mahesh M.S

27

Methods of predicting favorable mandibular growth rotations in growing patients – An Overview Vincy Antony, Prathapan Parayaruthottam

Regenerative endodontics – A review 31 Biji Balan

36 42

Digital Photo Stimulable Phosphor (PSP) radiography – A Review Mahesh M.S, Praveenkumar Ramdurg, Manjunath N

Oral clear cell tumors – A review Adarsh H, Suhas R Nayak.

47

Photodynamic therapy in periodontics

53

Microimplants in orthodontics

Rajeev K, Karthika R Tissa Francis, George M

Case reports:

58

Torus in Disguise–Rare cases of impacted supernumerary premolars Rachana.V.Prabhu, Prasanna Kumar Rao, Laxmikanth Chatra, Prashanth Shenai

61

Achondroplasia – A case report

65

Custom ocular prostheses: A clinical report

68

Nasal stent prosthesis - A case report Pramod Sankar S, Menon Prasad Rajagopal, Rajitha A.V

71

Skeletal class II correction with twin block appliance A case report

61

Sham Kishor.K, Navaneetha.C, Ramesh Kumaresan, Prasanna Kumar Rao Ramya R, Balasubramanya K.V, Govindaraj S.J

Shabeer N.N, Fawas Shaji, Reji Abraham, Pavithra U.S

Others

75

‘Health of the health care professional’ Are we caring ourselves enough?

Navaneetha C

71

Editorial JOURNAL OF DENTOFACIAL SCIENCES AND RESEARCH Editor-in-Chief

Manjunath. N Executive Editor

T.Vijayakumar

MESSAGE FROM THE EDITOR- IN-CHIEF

I

t gives me immense pleasure and satisfaction bringing out this inaugural issue of Journal of Dentofacial sciences and Research (JDSR), which reflects some of the diversities, and challenges that we as practitioners must learn to cope with on a daily basis. Members of our academy, as well as concerned clinicians at large, seek a comprehensive and integrated source of information that can contribute to their professional and personal needs.

By its very nature, dentistry challenges us to provide quality care within a framework of multiple inputs and the ever-present competitive edge. Multitasking therefore becomes part and parcel of our clinical skills and any resource that can assist in making our work easier and more fulfilling should be a welcome addition.

I take this opportunity to congratulate my editorial team and all those who have collaborated closely to the inception of our Journal and I wish to express my sincere gratitude to the Managing Director, Mr. Nasser Killiyamannil of Educare institute of Dental sciences for his invaluable support and resources. They have altogether contributed in finally making this, the inaugural issue of the Journal of Dentofacial Sciences and research a long-awaited reality.

Associate Editors

Pramod Shankar Mahesh M.S Rajeev Chandran Suhas Nayak Tissa Francis Technical Editors

Sunith George Adarsh. H Jaini Vijesh Karthika Editorial Committee

Abraham Thomas Scaria Abraham Vimal kumar Ajay Kumar Haridas Yadav Chakravarthy Paul V.J Prasad Rajagopal Rekha Raghavan Shameem Vincy Antony Anna Abraham Jayakrishnan Paul C.A Ratheesh Ajay Advisory Board

Manjunath Editor-in-Chief

M Ram Manohar DM Vasudevan IPE Varghese Mahesh Varma Cover Design:

Hema Mujeeb Rahman.N

MD's Message

Message

I

t provides me immense pride and satisfaction to know that the first issue of the "Journal of Dentofacial Sciences and Research" a quality academic publication brought out by the ECIDS is all set to reach the readers. The Journal is the result of the concerted efforts of the eminent scholars in dental sciences from all over the country. The credit for taking the initiative for such an endeavor however belongs to the faculty of ECIDS. We are aware that the number of medical colleges, dental colleges and other health care educational institutions in the country has seen an enormous increase during the past one decade.

Unfortunately, the number of quality journals to disseminate the latest research and developments in the healthcare sector in the country has not kept pace with the increase in the number of educational institutions. There has been a long felt need for a quality journal in dental sciences and the attempt by the faculty of ECIDS is towards fulfilling it. I am sure that the editorial team of the ECIDS faculty will go a long way in making the latest developments available to the discerning readers. I take this opportunity to congratulate the team and wish them all success and hope that the Journal will soon attain the status of globally benchmarked and peer-reviewed quality publication.

Nasser Killiyamannil Managing Director

Educare institute of dental sciences, College road, Chattiparamba, Malappuram district, 676 504 Kerala State, India

Research articles

Use of single Ni-Ti instrument for the preparation of canal on a curved resin block – A comparitive study Krishna Prasad Shetty1, Sandeep Rajalbandi2, S.V. Satish 3 1. Professor 2. Senior Lecturer 3.Reader Department of Conservative Dentistry and Endodontics, Navodaya Dental College & Hospital, Navodaya Nagar, Raichur, Karnataka.

Correspondence: Dr. Krishna Prasad Shetty, 201, Diamond Block, Presidency Enclave, Mangalore, Karnataka. e-mail: kprasad11@gmail.com

Abstract Aim: To describe a novel canal preparation technique using only one Ni-Ti rotary instrument and to evaluate the maintenance of original canal curvature in resin blocks with simulated canals.

Materials and methods: Ten resin blocks with simulated curved canals were used in this study. Their initial images were scanned. Canals in the first two resin blocks were prepared by using sequence of rotary Ni-Ti files according to manufacturer's instructions to size F2 till working length and the remaining 8 resin blocks were prepared using this novel technique. The canal was initially negotiated to the working length with a size 08 hand file. The canal preparation is then completed with an F2 ProTaper instrument used in a reciprocating handpiece. After preparation, their images were scanned again in the same position. Pre and post preparation images were superimposed by Photoshop software.

Results: There was no significant difference at any points in canals prepared with both the techniques. Removed material of inner canal wall and the outer canal wall was not significantly different between the control samples (n=2) and the test samples (n=8).

Conclusion: The advantages of the technique include a reduced number of instruments, lower cost, reduced instrument fatigue, and the elimination of possible prion cross-contamination associated with multiple use of endodontic instruments. Original canal curvature is maintained with both the techniques of canal preparation.

Keywords: Ni-Ti, Preparation, ProTaper, Reciprocation, Rotary, Single use.

Introduction Canal shaping is a critical phase of endodontic treatment because it influences the outcome of the subsequent phases of canal irrigation, filling and the success of the treatment itself. Once the canal is prepared, it should have a uniformly tapered funnel shape.1 Traditionally, the shaping of root canal was achieved by the use of stainless steel hand files. However, nickeltitanium (Ni-Ti) instruments offer many advantages over conventional files. They are flexible have increased cutting efficiency and have improved time efficiency.2 Furthermore, Ni-Ti instruments maintain the original canal shape during preparation and have a reduced tendency to transport the apical foramen.3 With all these apparent advantages, the use of Ni-Ti rotary systems has increased considerably since their introduction.

However, the clinician is faced with two major concerns when considering the use of Ni-Ti rotary instruments; (i) possibility of instrument fracture associated with increased instrument fatigue caused by the repeated use and (ii) the possibility of cross

contamination associated with the inability to adequately clean and sterilize endodontic instruments.

Tooth structure and organic debris were observed on the surface of Ni-Ti rotary instruments, and appeared to adhere in the surface cracks despite meticulous ultrasonic cleaning and decontamination.4 Therefore, the single use of endodontic instruments was recommended to reduce instrument fatigue and possible cross contamination.

But the single use of endodontic instruments and, mainly the more expensive Ni-Ti rotary instruments, may become an economical burden to the dentist especially as the available techniques involve the use of at least three to four Ni-Ti rotary instruments.

The purpose of this article was to describe a novel canal preparation technique using only one Ni-Ti rotary instrument. This novel technique will reduce the number of Ni-Ti rotary instruments required for canal preparation, simplify the armamentarium and would be more cost-effective compared with other Ni-Ti rotary techniques and also to evaluate the maintenance of original canal curvature after canal preparation with this technique.

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Use of single Ni-Ti instrument for the preparation of canal on a curved resin block – A comparitive study

Materials and methods Ten transparent resin simulated root canal blocks (Dentsply, Maillefer, Switzerland) were used to assess instrumentation. All the resin blocks have similar canal length (16mm) and similar canal curvature. Preoperative images of resin blocks were obtained using a scanner (Power look 1000, Umax) in a transmissive mode.5 The canals were filled with dye before scanning to make them more prominent (Fig.1).

Technique description The procedure carried out in this study was described

by G.Yared in 2007. The technique is simple and straightforward. It involves the use of only one size 08 hand instrument and one F2 ProTaper Ni-Ti rotary instrument (Dentsply Tulsa, USA).6 Initial canal negotiation: The canal is negotiated to the working length, with a stainless steel size 08 hand file.

This step is accomplished with the copious intracanal lubricant and irrigant.

Canal preparation: An F2 ProTaper Ni-Ti rotary instrument is used for the canal preparation in a clockwise (CW) and counterclockwise (CCW) movement. The F2 is used in conjunction with a reduction ratio contra angle handpiece (TEP E-10R, NSK Japan) which allows the reciprocating movement. The rotational speed is set at 400 rpm. As the handpiece is meant for hand files, the F2 rotary file is modified by placing a rubber tube over the shaft of the file to increase its diameter (Fig. 2).

The F2 instrument is used in the canal with a slow pecking motion and an extremely light apical pressure until resistance is encountered. The instrument is then pulled out of the canal, cleaned with gauze to remove the debris filling the flutes, and reinserted and employed in the same manner.

This step is repeated until the instrument reaches the working length. No further enlargement would be required for narrow and/or curved canals. For larger canals, hand files can be used after the F2 reaches the working length to complete the apical enlargement.

Of 10 samples, the first two samples were prepared using the set of ProTaper files (Dentsply Tulsa, USA) in sequence to size F2 till working length. Canal preparation was done following manufacturer's instructions with EndoMate DT Endomotor (NSK, Japan). These two samples served as control (Fig. 3). It was found that the canals prepared using the full sequence were well flared and maintained the canal curvature well without any deviation from the original.

In remaining 8 samples, canal preparation was done using only one F2 ProTaper NiTi rotary instrument with a reciprocating handpiece as described earlier (Fig. 4).

After the canal preparation all 10 samples were filled with a dye to appreciate the canal out line and canal curvature.

8

Each block was then scanned in the previously fixed position. Superimposition of the pre and post operative specimens was aided by landmarks placed in the sides of the resin blocks. The superimposed pre and post instrumentation stored images were analyzed using the Adobe Photoshop 8 software which magnified the canal images 10 times4 (Fig.5).

Results • It was observed that there was no straightening of canals.

• Canals prepared with only F2 were similar to control samples in respect to maintenance of original canal curvature.

Discussion The technique described involves the use of only one hand instrument and one Ni-Ti rotary instrument.

The F2 ProTaper instrument is able to cut dentine in both directions, CW (clock wise) and CCW (counter clock wise). Also, this instrument, with a 0.08 mm/mm taper at its tip, would provide an ideal shape to allow the filling of the root canal system even with the vertical compaction of warm gutta percha.7 An interesting design feature of ProTaper finishing files is their variable taper. As such, if the entire length of the file had a uniform 8% taper it would make the file too rigid for use in curved canals. But modern manufacture techniques enable the production of the instruments with an 8% taper at the tip which reduces to 5.5% further up the shaft, thereby making them flexible.8 An effective way to prepare curved canals when using hand files in a CW and CCW movement has been described.9 Ni-Ti rotary instruments used in a continuous CW rotation also allow the preparation of curved canals.

However, several instruments are required to completely shape a canal. Hand files may also be required for increased apical enlargement. In the present technique only one rotary ProTaper Ni-Ti instrument was used regardless of the canal width and the desired degree of apical enlargement. Although in the present technique the instrument would frequently engage dentine at its tip, the CCW rotation would immediately disengage the instrument. Theoretically, the CW and CCW movement would reduce the incidence of torsional fracture by taper lock. However, this issue needs to be investigated further.

In the standard Ni-Ti techniques using continuous rotation, it is crucial to enlarge the canal to at least a size 15 file prior to the use of rotary instruments. If not, although the instrument would still advance in the canal, it would bind in dentin and instrument may fracture due to taper lock.9,10 According to G. Yared6 the F2 instrument is used in conjunction with a 16:1 reduction ratio contra angle

JOURNAL OF DENTOFACIAL SCIENCES AND RESEARCH 2011; 1(1):7-10

Krishna Prasad Shetty, Sandeep Rajalbandi, S.V. Satish

connected to an ATR Vision (ATR, Pistoia, Italy) motor which allows reciprocating movement. The CW and the CCW movements are set on the motor at four tenth and two tenth of a circle. The rotational speed is set at 400 rpm. At the present time, the ATR Vision motor is the only one available in North America to allow the setting of the specific values of the CW and CCW rotations. Hence, in this study a contra angled reciprocating handpiece (TEP E-10R, NSK Japan) was used, which allows 900 CW and CCW rotations.

However, even this showed a favorable outcome.

Conclusion A novel canal preparation technique with only one Ni-Ti rotary instrument used in a clockwise and counterclockwise movement is described. This technique would offer two major advantages: (i) the single use of endodontic instruments would become more cost effective and (ii) the elimination of possible prion crosscontamination and reduced instrument fatigue associated with the single use of endodontic rotary files. From this study it can also be concluded that canal preparation with only F2 could maintain the original canal curvature.

The experience with this technique was encouraging. However, the need for proper laboratory and clinical evaluation of several parameters (apical extrusion of debris, incidence of instrument fracture, canal transportation, need of pre flaring etc.) would be essential.

References 1. Schilder H. Cleaning and shaping the root canal, Dental Clinics of North America 1974; 18:269.

2. Walia H. An initial investigation of the bending and torsional properties of nitinol Root canal files.

Journal of Endodontics 1988;14:246.

3. Kuhn WG, Carnes DL Jr, Clement DJ, Walker WA. Effect of tip design of nickel-titanium and stainless steel files on root canal preparation. Journal of Endodontics 1997;23:735738.

4. Alapati SB, Brantley WA, Svec TA, Powers JM, Nusstein JM, Daehn GS. Proposed role of embedded dentin chips for the clinical failure of nickel-titanium rotary instruments. Journal of Endodontics 2004;30:339334.

5. Nahid Mohammadzade Akhlaghi, MS, Zohreh Khalilak, Ladan Baradaran Mohajeri, Mahshid Sheikholeslami, Saeed Saedi. “Comparison of canal preparation pattern of K3 and ProTaper rotary files in curved resin blocks�. Iranian Endodontic journal 2008;3(2):11-16.

6. G Yared. Canal preparation using only one Ni-Ti rotary instrument: preliminary observations.

International Endodontic Journal 2008;41:339344.

7. Syngcuk Kim. Modern endodontic practice: instruments and techniques; Dental Clinics of North America Jan 2004;48(1):1-9.

8. Alapati SB, Brantley WA, Svec TA, Powers JM, Mitchell JC. Scanning electron microscope observations of new and used nickel-titanium rotary files. Journal of Endodontics 2003;29:667669.

9. Peters OA, Peters CI, Schonenberger K, Barbakow F. ProTaper rotary root canal preparation: assessment of torque and force in relation to canal anatomy.

International Endodontic Journal 2003;36:9399.

10. Berutti E, Negro AR, Lendini M, Pasqualini D. Influence of manual preflaring and torque on the failure rate of ProTaper rotary instruments. Journal of Endodontics 2004;30:228230.

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Use of single Ni-Ti instrument for the preparation of canal on a curved resin block – A comparitive study

Pictures

Fig. 1: Scanned pre operative images of the resin blocks.

Fig. 4: Preparation of the resin block with the F2 file in the reciprocating hand piece

Fig. 5: Superimposition of scanned pre and post operative images to evaluate preparation

Fig. 2: Reciprocating hand piece and F2 file that has been modified by placing a rubber tube over the shaft of the file.

Fig. 3: Preparation of a resin block with ProTaper files in an Endomotor

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Review article

Biofilms in endodontics – A review Yadav Chakravarthy1 1. Professor, Department of Conservative Dentistry and Endodontics, Educare Institute of Dental Sciences, Malappuram, Kerala.

Correspondence: Yadav Chakravarthy, Professor, Department of Conservative Dentistry and Endodontics, Educare Institute of Dental Sciences, Malappuram, Kerala.e-mail: yadavchakravarthy@gmail.com

Abstract: The slippery coating on river-stone edges (pond scum), the 'slime' that coat drains, etc. are few routinely encountered “Biofilms”. Microbial infections around biomaterials placed in humans, (e.g. heart valves, vascular prosthesis, dental implants, etc.), and dental plaque, are also types of bacterial biofilm. 'Biofilms' can exist on any solid wet surface, harboring microorganisms which are responsible for most recalcitrant infections. Usually, they maybe undetectable but however, with advanced techniques besides the conventional iodine staining and light microscopy, we can view its ultrastructure. They are rather resistant to antimicrobials compared to their planktonic counterparts, yet with methods such as the use of laser and bacteriophage therapy, etc., biofilms can be controlled and eradicated.

Biofilm formed on the tooth surface is harmless under normal conditions. Nevertheless, a shift in microenvironment due to repeated use of “habit-forming” substances, diet and host immune response can lead to biofilm-mediated infections or diseases in the oral cavity. Through quorem sensing, an exchange of genetic material occurs which lead to their adaptive evolution. In endodontics, presence of intracanal biofilms, extraradicular biofilms, periapical biofilms, and biomaterial centered infections have been documented and researched upon, such that innovative treatment modalities for successful endodontic treatment can be initiated.

Keywords: Biofilm ultrastructure, Characteristics, Quorem sensing, Formation stages, Ecological plaque hypothesis, Endodontic biofilm.

Introduction A Biofilm is a community of microorganisms (bacteria, fungi, yeast, protozoa, etc.) which is attached to a solid surface. These microorganisms are usually encased in an extracellular polysaccharide that they themselves synthesize.1 It is a mode of microbial growth where dynamic communities of interacting sessile cells are irreversibly attached to a solid substratum, as well as to each other, and are embedded in a self-made matrix of extracellular polymeric substances (EPS)3 (Fig.1). In layman terms, it refers to the thin-layered condensations of microbes on various surface structures. In dental contexts, it is established during the attachment of bacteria to the tooth surfaces to form dental plaque. Here, the planktonic bacteria suspended in the saliva serve as the primary source for the organization of this specific biofilm.4 Biofilms can be formed wherever there is a flow of fluid, microorganisms and a solid surface. The sessile bacterial cells in a biofilm state differ greatly from their planktonic counterparts. Inside a biofilm, they exhibit altered phenotypic properties, are more pathogenic, and are protected from antimicrobials, environmental stresses, bacteriophages and phagocytic amoebae. This explains

why biofilms are responsible for most of the chronic infections and almost all recalcitrant infections in human beings as bacteria in a biofilm are resistant to both antibiotic therapy and host defense mechanisms. However, common biofilms found in the oral cavity and gastrointestinal tract are protective in nature. These biofilms, featuring a large number and diverse array of commensal bacteria, hinders adherence of pathogenic microorganisms.3

Ultra\structure of Biofilm The basic structural unit of a biofilm is the micro-colonies or cell clusters formed by surface adherent bacterial cells. A glycocalyx matrix made of EPS surrounds the micro-colonies and anchors the bacterial cell to the substrate. A fresh biofilm is made up of biopolymers such as polysaccharides, proteins, nucleic acids, and salts. The structure and composition of a mature biofilm is known to modify according to environmental conditions i.e., growth conditions, nutritional availability, nature of fluid movements, physiochemical properties of the substrate, etc. Typically, a viable, fully hydrated biofilm appears as “tower-” or “mushroom-”shaped structure adherent to a substrate3 (Fig.2).

The structural feature of a biofilm that has the highest impact in chronic bacterial infection is, the tendency of microcolonies to detach from the biofilm

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Biofilms in endodontics – A review

community. During the process of detachment, the biofilm transfer particulate constituents (cells, polymers, and precipitates) from the biofilm to the fluid bathing the biofilm.5 There are 2 main types of detachment process (Fig.3): erosion the continual detachment of single cells and small portions of the biofilm; and sloughing the rapid, massive loss of biofilm.3 Detachment is considered as an active dispersive mechanism (seeding dispersal). These detached cells, which have acquired the resistance traits from the parent biofilm community can be source for persistent infection.3

Characteristics of biofilm A microbial community has 4 basic criteria. The microorganisms (i) must possess abilities to selforganize (autopoiesis); (ii) resist environmental pertubations (homeostasis); (iii) must be more effective in association than in isolation (synergy); (iv) respond to environmental changes as a unit rather than single individuals. (Communality).6

Nutrient trapping and establishment of metabolic co-operativity in a biofilm Biofilms are very heterogeneous, containing microcolonies of bacterial cells encased in an EPS matrix and separated from other microcolonies by interstitial voids (water channels). The highly permeable and interconnected water channels in the biofilm provide an excellent means for material exchange. The water channel connects the outer fluid medium with the interior of the biofilm, ensuring nutrient availability to microbial communities deep in the biofilm structure.7,4,3 The breakdown of glycoproteins and proteins supplied by saliva and gingival crevicular fluid requires sequential action of a range of proteases, peptidases and glycosidases. Distinct oral bacterial species possess restricted repertoires of these extracellular enzymes and consequently grow poorly in the presence of complex nutrients in monospecies culture.4 Due to the juxtapositioning of different microorganisms, cross-feeding and metabolic cooperativity between different species of microorganisms are seen in a biofilm. Each bacterial species possess different array of lytic enzymes, and biofilm as a unit is equipped with a wide spectrum of enzymes that can degrade complex organic materials.

For instance, bacterial species possessing proteolytic enzymes make nutrients available to all other bacteria in a protein rich environment.7,3

Protection of biofilm bacteria from environmental threats Bacteria in a biofilm state show distinct capacity to survive tough growth and environmental conditions.

This unique capacity is due to (i) the biofilm structure which protects the residing bacteria from environmental threats; (ii) which permits trapping of nutrients and metabolic cooperativity between resident cells of same/different species, (iii) display organized internal compartmentalization which allows bacterial species with different growth requirements to survive in each compartment; and (iv) bacteria cells in a biofilm may communicate and exchange genetic materials to acquire new traits.3 Bacteria residing in a biofilm community experience certain degree of protection and homeostasis (Fig.4). Many bacteria are capable of producing polysaccharides either as cell surface structures (e.g. Capsule) or as extracellular excretions (e.g. EPS). EPS covers biofilm communities and creates a micronische favorable for the long-term survival and functioning of the bacterial communities. EPS protects the biofilm bacteria from a variety of environmental stresses, such as UV radiation, pH shifts, osmotic shock and d e s i c c a t i o n . D i ff u s i o n i s t h e p r e d o m i n a n t transport process within cell aggregates. 3 A biofilm that is 10 cells thick will exhibit a diffusion time 100 times longer than that of a single cell.9 Diffusion of compounds into the biofilm depends upon the nature of both the compound and the EPS matrix.

EPS can physically prevent the permeability of certain compounds into the biofilm by acting as an ion exchanger.10, 11

Quorum sensing communication Exchange of genetic materials and acquiring of new traits Communications between bacterial cells residing in a biofilm is attained through signaling molecules by a process called quorum sensing (Fig. 5 and 6). Quorum sensing is mediated by low molecular weight molecules, which in sufficient concentration can alter the metabolic activity of neighboring cells and coordinate the functions of resident bacterial cells within a biofilm.3,4 Exchange of genetic materials between bacterial species residing in a biofilm will result in in the evolution of microbial communities with different traits. Close proximity of the cells facilitates genetic exchange between bacteria of genetically distant genera. The horizontal gene transfer is of importance in human diseases caused by bacterial biofilm as it can result in the generation of antibioticresistant bacteria population.3 Gene transfer between bacteria residing in a biofilm is thought to be mediated by bacterial conjugation. The presence of diverse bacterial species in a biofilm presents a pool of genetic codes for nutrient breakdown, antibiotic resistance, and xenobiotic metabolism.3

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Yadav Chakravarthy

Development of biofilm Bacteria can form biofilms on any surface that is bathed in a nutrient-containing fluid.4 The three major components involved in biofilm formation are: bacterial cells, a solid surface, and a fluid medium (Fig.7).3

Stages of biofilm formation Biofilm formation takes place in 3 stages3,4,7 (Fig.8), starting with adsorption of macromolecule proteins in the planktonic phase to the surface, leading to the formation of a conditioning film. Next, the adhesion and coadhesion of the planktonic bacteria occurs followed by the last stage which involves growth and metabolism by adherent bacteria, resulting in a structurally organized mixed microbial community.

During the first stage, the planktonic proteins are adsorbed onto the tooth surface, leading to formation of a conditioning film.13 On tooth surfaces, the conditioning film is comprised of proteins, glycoproteins from saliva and gingival crevicular fluid and some secreted microbial products.4 The conditioning film is always formed prior to the arrival of microorganisms and selectively promotes adhesion of certain microorganisms.4 In the second stage, adhesion and co-adhesion of microorganisms, and attachment maybe strengthened through polymer production and unfolding of cell surface structures. Streptococcal strains are among the early colonizers on tooth surfaces and appear to provide important features for the subsequent attachment of both Gram positive and Gram negative organisms.4 In the last stage, growth and metabolism by adherent bacteria occurs. During this stage, the monolayer of microbes attracts secondary colonizers forming microcolony and the collection of microcolonies gives rise to the final structure of biofilm. A mature biofilm will be a metabolically active community of microorganisms where individuals share duties and benefits i.e., some will help in adhering to the solid support while some others create bridges between different species, which otherwise would not have happened.

Detachment of microorganisms should be seen as a continuous process during development. The monolayers of oral bacteria release enzymes that mediate their attachment. The fact that microorganisms detach regularly has implications for their spreading and colonization to other sites.4 Two types of microbial interactions occur at the cellular level during the formation of biofilm: coadhesion, which is the process of recognition between a suspended cell and a cell already attached to the substratum and co-aggregation, in which the genetically distinct cells in suspension recognize each other and clump together (Fig. 9). These associations are highly specific and occur between co-aggregating partners only3, for example, F. nucleatum, a Gram ve filamentous

anaerobe can co-aggregate with all oral bacteria and can act as a bridging bacterium that bind together even nonaggregating bacteria.

The association of long filamentous bacteria and surface-adsorbed sphericalshaped cocci produce the characteristic corncob structure of oral biofilms. The attachment of cocci to filamentous bacteria is said to be mediated via fimbriae of the oral streptococci.

Resistance of microbes in biofilm to antimicrobials The biofilm's structure and the physiological characteristics of biofilm microbial contribute to its resistant to antimicrobial agents such as antibiotics, disinfectants and germicides. The resistance to antimicrobial agents has been found to amplify more than thousand times for microbes in biofilm when compared to planktonic cells. Mechanisms (Fig.10) responsible for the resistance to antimicrobial agents include the following: (1) resistance associated with the extracellular polymeric matrix, (2) resistance associated with growth rate and nutrient availability, and (3) resistance associated with the adoption of resistance phenotype. Although there are evidences to support each of these mechanisms, no single mechanism may account for the general resistance to antimicrobial.3

Biofilms in dentistry Oral bacteria have the capacity to form biofilms in distinct surfaces ranging from hard to soft tissues. The characteristics of the biofilm formed depend on the residing bacterial species, the surface or substratum composition and the conditioning layer coating the surfaces on which they are formed.3 While much emphasis is placed on the adverse effects of biofilms and the difficulties in treating biofilmmediated diseases, it must be understood that the biofilm formed by the commensals are protective in nature. The commensal bacterial biofilms inhibit colonization by exogenous pathogenic microorganisms by a phenomenon named colonization resistance.

For instance, dental biofilm (plaque) formed on the tooth surface is harmless under normal conditions.

Nevertheless, a shift in microenvironment due to repeated use of “habit-forming” substances, diet and host immune response can lead to biofilm-mediated infections or diseases in the oral cavity.3 According to the “ecological plaque hypothesis”, any environmental change that favors increasing colonization by potential pathogenic bacteria would cause disease.3 A decline in the host defense mechanisms caused by disease or immune-suppressive medicaments may render generally “harmless” commensals to become “opportunistic pathogens”. The nature and activity of

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Biofilms in endodontics – A review

bacteria associated with site-specific biofilms manifest as various dental infections. Dental caries, gingivitis, periodontitis, peri-implantitis, and periapical (apical) periodontitis are examples of diseases caused by biofilm community (biofilm-mediated diseases) rather than any single organism (Koch's postulate).

Endodontic biofilms Endodontic microbiota is established to be less diverse than the oral microbiota. This transition in the microbial population is more conspicuous with the progression of infection. Progression of infection alters the nutritional and environmental status within the root canal. The root canal environment apparently becomes more anaerobic and the nutritional level will be more depleted. These changes will offer a tough ecological niche for surviving microorganisms.3 Microbes are found to persist in anatomical complexities such as isthmuses, deltas and apical region of the root canal system, which shelter the adhering bacteria from cleaning and shaping procedures. Because biofilm is the manner of bacterial growth, to survive unfavorable environmental and nutritional conditions the root canal environment in both primary and posttreatment infections will favour biofilm formation.

Additionally, the biofilm mode of bacterial growth offers other advantages i.e., resistance to antimicrobial agents, continuation of nutrients, and opportunity for genetic material exchange, ability to communicate between bacterial populations of same and/or different species, and produce growth factors across species boundaries.3 Endodontic bacterial biofilms can be categorized as: intracanal biofilms, extraradicular biofilms, periapical biofilms, and biomaterial centered infections.3 Intracanal microbial biofilms are microbial biofilms formed on the root canal dentin of an endodontically infected tooth. A detailed description on the intracanal bacterial biofilm was documented by Nair in 1987.14 He examined the root canal content of thirty-one teeth with gross coronal caries and to which the periapical inflammatory process was attached upon extraction. He noted the “loose collections” of cocci, rods, filaments, and spirochetes. While most of these organisms appear suspended in a moist canal space, dense aggregates were also observed sticking to the canal walls, forming thin to thick layers of bacterial condensations.

Extraradicular microbial biofilms are also termed root surface biofilms, which refers to the biofilms formed on the cementum surface adjacent to the surface adjacent to the root apex of endodontically infected teeth. They were reported in teeth with asymptomatic periapical periodontitis and teeth with chronic apical abscesses associated with sinus tracts. Tronstad et al. examined ten

root tips removed during surgical treatment of root-filled teeth with post-treatment disease.15 Mature bacterial biofilms were found in many areas of the apical root surfaces. A smooth, structureless biofilm, consisting of extracellular matrix material with embedded bacterial cells was noticed to coat the apex of the root tip adjacent to the apical foramen. Ricucci et al. has reported the presence of calculus-like deposit on the root apex of teeth extracted due to post-treatment apical periodontitis.8 Periapical microbial biofilms are isolated biofilms found in the periapical region of an endodontically infected teeth. Periapical biofilms may or may not be dependent on the root canal. The microbiota associated with apical periodontitis is restricted to the root canal, as most of the microbial species that infect the root canal are opportunistic pathogens that do not have ability to survive host defense mechanism in the periapical tissues. Members of the genus Actinomyces and the species P. propionicum have been demonstrated in asymptomatic periapical lesions refractory to endodontic treatment.9,16 These microorganisms have the ability to overcome host defense mechanisms. Thus, thrive in the inflamed periapical tissue and subsequently induce a periapical infection.3 In endodontics, the biomaterial-centered biofilms would form on the root canal obturating materials.

These biofilms can be intra- or extra-radicular depending upon whether the obturating material is within the root canal space of has it extruded beyond the root apex. In a clinical investigation, six teeth and five extruded gutta-percha points associated with refractory periapical disease were investigated. Nine out of the eleven samples examined showed bacterial biofilms in the extra-radicular region. The gutta-percha surface was covered with glycocalyx-like structures, which shows predominantly filaments, long rods and spirochete-shaped bacteria. Because biofilms are extremely resistant to host defense mechanisms and antibiotic treatments, biomaterial-centered infections are rarely resolved and often the only solution to an infected biomaterial such as implant is its surgical removal.3

Detection of biofilm Advances in detecting Biofilms have enabled us to view its ultrastructure at a different platform besides the conventional iodine staining and light microscopy. The recent reliable methods include: 1. Transmission electron microscopy (TEM)14 2. Scanning electron microscopy (SEM)17 3. Tissue culture plate method (TCP)18 4. Tube method (TM)19 5. Congo red Agar method (CRA)20

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Yadav Chakravarthy

Biofilm and antimicrobials A lot of research has been done to find efficient measures to control and eradicate biofilms. Then again, microbial communities grown in biofilms are difficult to eliminate with anti-microbial agents and microorganisms in biofilm can be notoriously resistant for reasons that have yet to be adequately explained.

Different concentrations of sodium hypochlorite (NaOCl) were used as an irrigants in the past seven decades because of its well-known antimicrobial effects and its ability to dissolve tissue. Previous studies have shown that instrumentation with sodium hypochlorite would eliminate bacteria in 50% to 75% of infected root canals at the end of the first treatment session where as the remaining root canals contain considerable bacteria. In a study by Nair et al., 88% of root canal treated mandibular molars revealed residual infection of mesial roots after instrumentation, irrigation with NaOCl, and obturation in a single visit treatment.21 The use of Mixture of tetracycline isomer, acid and detergent (MTAD)[Tween-80] as an irrigating solution has also been explored. Torabinejad et al. have shown that MTAD is able to safely remove the smear layer and that it is effective against E. faecalis, and also eliminate bacteria in human root canals that have been infected by whole saliva.22 A new irrigant, Tetraclean (a mixture of doxycycline hiclate at a lower concentration than MTAD, an acid, and detergents), (Ogna Laboratori Farmaceutici, Milano, Italy), is able to eliminate microorganisms and smear layer in dentinal tubules of infected root canals with a final four minute rins.23 According to a study by Luciano Giardino et al., 5.25% NaOCl was the only irrigant capable of removing biofilm after only five minutes, whereas the same effect was reached by Tetraclean after sixty minutes. Biopure MTAD (Dentsply Tulsa Dental, Johnson City, TN), was unable to reach this goal at every considered time. Furthermore, the use of Tetraclean was able to reduce 90% bacterial load after five minutes and 99.9% after thirty one minutes of application. The bacterial load reduction using Biopure MTAD has not been significant after five minutes, whereas it has been much lower after thirty one minutes than using Tetraclean or 5.25% NaOCl.24 In a study by Luis E. Chavez de Paz, Gunnar Bergenholtz, Gunnel Svens채ter, biofilms formed for twenty four hours were exposed for five minutes to alkali (pH = 12), chlorhexidine digluconate (2.5%), (EDTA) Disodium ethylenediamino tetra acetic acid (50 mmol/L), and sodium hypochlorite (1%). The biofilms were then characterized by using fluorescent markers targeting cell membrane integrity (live/dead) and metabolic activity (5cyano-2,3-ditolyl tetrazolium chloride and fluorescein diacetate). It was found that NaOCl (1%) affected the membrane integrity of all organisms and removed most

biofilm cells. Exposure to (EDTA) (50 mmol/L) affected the membrane integrity in all organisms but failed to remove more than a few cells in biofilms of E. faecalis, L. paracasei, and S. anginosus. Chlorhexidine (2.5%) had a mild effect on the membrane integrity of E. faecalis and removed only 50% of its biofilm cells. The effects were substratum-dependent, and most organisms displayed increased resistance to the antimicrobials on collagencoated surfaces.2

Recent advances in biofilm control A number of new strategies have been developed by researches to overcome the problems encountered in biofilm control in vitro. Although many of these are still under investigations and are being tested in clinical applications, they provide the key to future control strategies. These include: i.

Novel combinations of chemical and physical techniques to control biofilms, such as ultrasound or electrical enhancement of antibiotics.25,26,27

ii. Novel antibiotics derivatives with increased antibacterial activities.28 iii. Novel anti-adhesive compounds that prevent or inhibit bacterial binding to either tissue surfaces or implants, such as soluble receptor analogues, antibodies that block adhesion or compounds that prevent the expression of bacterial adhesions.29,30,31 iv. Use of 'probiotic' bacteria and fungi to prevent or remove microbial contamination. For example, the use of bacteria to prevent yeast contamination of artificial voice boxes. Such techniques are of great interest in terms of being cost effective and having a low impact on the environment.32,33 v.

'Smart surfaces' (which use biofilm inhibiting properties of a silver-palladium surface, that kills bacteria by generating microelectric fields and electrochemical redox processes. In the case of the silver-sensitive strain, the silver palladium surfaces killed the bacteria and prevented biofilm formation under conditions of low or high bacterial load. In the case of the silver-resistant strain, the silverpalladium surfaces killed surface-associated bacteria and prevented biofilm formation under conditions of low bacterial load, whereas under conditions of high bacterial load, biofilm formation occurred upon a layer of surfaceassociated dead bacteria34 that reduce or prevent biofilm growth and contamination.13 So, whilst materials can be developed that reduce fouling, such techniques may only delay and/or decrease contamination by up to 1.0 log CFUcm-2. Such materials maybe of interest for applications such as prosthetic hip replacement, where the material

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Biofilms in endodontics – A review

surface may present an initial challenge to microbial attachment. vi. Bacteriophage therapy that uses bacterial specific viruses to treat infections by causing bacterial cell lysis and death.7 Vii. By Er: YAG Laser irradiation.35

Conclusion Currently, our knowledge on Biofilms has been successively accumulating, particularly on their visualization, mechanisms, role in infections and measures to eradicate them.

Changes in the environment, such as an increase in pH by calcium hydroxide or the effect of antimicrobials, are capable of triggering genetic cascades that modify the physiological characteristics of bacterial cells. Surface adherence by bacteria to form biofilms is a good example of bacterial adaptation and one that is pertinent to endodontic infections. Information on the existence of polymicrobial biofilm communities on root canal walls, coupled with new data showing that the adaptive mechanisms of bacteria in these biofilms are significantly augmented for increased survival.

This ecological view on the persisting infection problem in endodontics, suggests that the action of individual species in persisting endodontic infections is secondary when compared to the adaptive changes of a polymicrobial biofilm community undergoing physiological and genetic changes in response to changes in the root canal environment.

The biofilm microbial resistance has led to interesting ideas such as the use of 'smart surfaces' and 'probiotic bacteria', to overcome its growth and contamination. Hence, it is imperative to understand, to realize the complexity and nature of the biofilm, especially the role it plays in harboring and protecting persistent infection-causing microorganisms, such that modalities can be instituted for successful endodontics therapy.

References: 1. Herbert N. Gutentag, Mark J. Gelband. Biofilms in Root Canals.

Http://www.redbankendodontics.com/referringdoctors/info-letters/biofilms.html. [Online] 2. Luis E Chavez de Paz, Gunnar Bergenholtz, Gunnel Svensater. The Effects of Antimicrobials on Endodontic Biofilm Bacteria. Journal of Endodontics 2010;36:70-77.

3. Ingle, John Ide. Ingle's Endodontics. 5th ed. BC Decker Inc; 2008.

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4. Gunnel Svensater, Gunnar Bergenholtz. Biofilms in endodontic infections. 2004. Endodontics topics 2004;9:27-36.

5. PS Stewart, BM Peyton, WJ Drury, R Murga.

Quantitative observations of heterogeneities in Pseudomonas aeruginosa biofilms. 1993. 1, January 1993, Applied and Environmental Microbiology 1993;59:327-329.

6. Bortolaia, Ludovico Sbordone, Claudia. Oral microbial biofilms and plaque-related diseases: microbial communities and their role in the shift from oral health to disease. Clinical Oral Investigations 2003;7:181-188.

7. Jana Jass, Susanne Surman, James T. Walker.

Medical Biofilms: Detection, prevention and control. John Wiley & Sons; 2003.

8. D. Ruccuci, M. Martorano, AL. Bate, EA. Pascon.

Calculus-like deposit on the apical external root surface of teeth with post-treatment apical periodontitis:report of two cases. International Endodontic Journal 2005;38:262-271.

9. Hornef M, Wick MJ, Rhen M, Normark S. Bacterial strategies for overcoming host innate and adaptive immune responses. National Immunology 2002;3(11):1033-1040.

10. Stoodley P, Lewandowski z, Boyle JD, LappinScott HM. Oscillation characteristics of biofilm streamers in turbulent flowing water as related to drag and pressure drop. Biotechnol Bioeng 1998;57:536-544.

11. David M, OToole GA. Microbial biofilms: from ecology to molecular genetics. Microbiol Mol Biol Rev 2000;64:847-867.

12. Center for Biofilm Engineering at MSUBozeman;2003. http://www.biofilm.montana.edu/.

[Online] 13. Lisbeth R. Hilbert, Dorthe Bagge-Ravnb, John Koldc, Lone Gram. Influence of surface roughness of stainless steel on microbial adhesion and corrosion resistance. International Biodeterioration & Biodegradation 2003;52:175-185.

14. Nair PNR. Light and electron microscopic studies on root canal flora and periapical lesions. J Endod 1987;13:29-39.

15. Leif Tronstad, Frederic Barnett, Kenneth Riso, Jorgen Slots. Extraradicular endodontic infections.

Dental Traumatology 1987;3:8690.

16. O'Grady J, Reade PC. J Endodon. Periapical actinomycosis involving Actinomyces israelii. h t t p : / / w w w. j e n d o d o n . c o m / a r t i c l e / S 0 0 9 9 2399(88)80217-6/. [Online]

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Yadav Chakravarthy

17. BH Sen, B Piskin, T Demirci. Observation of bacteria and fungi in infected root canals and dentinal tubules by SEM. Dental Traumatology. http://onlinelibrary.wiley.com/doi/10.1111/j.160 0-9657.1995.tb00671.x/abstract. [Online] 18. Christensen GD, Simpson WA, Younger JA, Baddour LM, Barrett FF, Melton DM et al.

Adherence of cogulase negative Staphylococi to plastic tissue cultures:a quantitative model for the adherence of staphylococci to medical devices. J Clin Microbiol 1985;22:996-1006.

19. Simpson WA, Bisno AL, Beachey EH, Christensen GD. Adherence of slime-producing strains of Staphylococcus epidermidis to smooth surfaces.

Infect Immun 1982;37:318-326.

20. Freeman DJ, Falkiner FR, Keane CT. New method for detecting slime production by coagulase negative staphylococci. J Clin Pathol 1989;42:872-874.

21. Nair PN, Henry S, Cano V, Vera J. Microbial status of apical root canal system of human mandibular first molars with primary apical periodontitis after "one-visit" endodontic treatment. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2005;99(2):231-252.

22. Torabinejad, Shahrokh Shabahang, Raydolfo M. Aprecio, James D. Kettering. The Antimicrobial Effect of MTAD: An In Vitro Investigation. Journal of Endodontics 2003;29(6):400-403.

23. Chavez De Paz LE, Dahlen G, Molander A, Moller A, Bergenholtz G. Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment. Int Endod J 2003;36:500508.

24. Luciano Giardino, Emanule Ambu, Enrico Savoldi, Roberto Rimondini, Clara Cassanelli, Eugenio A. Debbia et al. Comparative Evaluation of Antimicrobial Efficacy of Sodium Hypochlorite, MTAD and Tetraclean Against Enterococcus faecalis Biofilm. Journal Of Endodontics 2007;33:852-855.

25. Jana Jass, Hilary M, Lappin-Scott. The efficacy of antibiotics enhanced by electrical currents against Pseudomonas aeruginosa biofilms. Journal of Antimicrobial Chemotherapy 1996;38: 987-1000.

26. Wattanakaroon W, Stewart PS. Electrical enhancement of Streptococcus gordonii biofilm

killing by gentamicin. Archives of Oral Biology 2000;45:167-171.

27. Rediske et al. Effect of pulsed ultrasound in combination with gentamicin on bacterial viability in biofilms on bone cements in vivo. Journal of Applied Microbiology 2005;99:443-448.

28. Ishikawa T, Kamiyama K, Nakayama Y, Iizawa Y, Okonogi K, Miyake A. Studies on anti-MRSA parenteral cephalosporins IV. A novel water-soluble Nphosphono type prodrug for parental administration.

Journal Of Antibiotics 2001;54:364-74.

29. Scott J. Hultgren, Frederik Lindberg, Goran Magnusson, Jan Kihlberg, Jan. M. Tennent, Staffan Normark.The PapG Adhesion of Uropathogenic Escherichia coli Contains Separate Regions for Receptor Binding and for the Incorporation into the Pilus. Proceedings of the National Academy of Sciences of the United States of America. National Academy of Sciences 1989;(86):4357-4361.

30. Flock JI, Brennan F. Antibodies that block adherence of to fibronectin. Trends in Microbiology 1999;7:140-141.

31. Majlis Svensson, Bjorn Frendeus, Terry Butters, Frances Platt,Raymond Dwek, Catharina Svanborg.

Glycolipid depletion in antimicrobial therapy.

Molecular Microbiology 2003;47:453461.

32. H. J. Busscher, G. I. Geertsema-Doornbusch, H. C. van der Mei. Adhesion to silicone rubber of yeasts and bacteria isolated from voice prostheses: Influence of salivary conditioning films. Journal of Biomedical Materials Research 1997;34:201209.

33. Ligia Rodrigues, Henny C. van der Mei, Jose Teixeira, Rosario Oliveira. Influence of Biosurfactants from Probiotic Bacteria on Formation of Biofilms on Voice Prostheses. Applied and Environmental Microbiology 2004;70:44084410.

34. Wen-Chi Chiang, Casper Schroll, Lisbeth Rischel Hilbert, Per Møller, Tim Tolker-Nielsen. SilverPalladium Surfaces Inhibit Biofilm Formation. Appl Environ Microbiol 2009; 75(6):16741678.

35. Stewart, George A O'Toole, Philip S. Biofilms strike back. Nature Biotechnology 2005;23:1378 -1379.

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Biofilms in endodontics – A review

Pictures

Fig. 4 Biofilm Protection8 Fig. 1 Structure of A Polymicrobial Biofilm2

Fig. 5 Quorem sensing12

Fig. 2 Schematic representation of a mature biofilm3

Early biofilm

Mature biofilm

Detachment (seeding dispersal)

Fig. 3 Detachment of microcolonies 3

Fig. 6: Cell-cell communication in a biofilm. Some bacteria can produce chemical signals (green) and other bacteria from the same species or from other different species or strain can respond to them (red).3

Fig. 7 Components involved in Biofilm Formatiion (29)

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Yadav Chakravarthy

Co-aggregation

Co-adhesion Early biofilm

Mature biofilm

Fig. 9 Co-aggregation and Co-adhesion3

Detachment (seeding dispersal)

Fig.8 Stages of biofilm formation3

Fig. 10 Mechanisms Responsible For Antimicrobial Resistance3

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Review article

Differential diagnosis of swellings In the floor of the mouth Manjunath N1, Mahesh MS2 1. Reader, 2. Senior lecturer Dept of Oral Medicine & Radiology, Educare Institute of Dental Sciences, Chattiparamba, Malappuram Correspondence: Manjunath N, Reader, Dept of Oral Medicine & Radiology, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala. e-mail: manjoo021@rediffmail.com

Abstract Floor of the mouth swellings could pose a conflicting diagnosis. The common occurrences of superficial ranula and sialoliths often simplify the possible diagnosis and enhance the likelihood of misdiagnosing a more serious malignant tumor. Further, diagnosis may be more difficult when an asymptomatic swelling is discovered during a routine oral examination and the patient is unaware of its presence. This article reviews the clinical characteristics of spectrum of conditions that present as swelling in the floor of the mouth and presents a classification based on their origin that can aid dentists in their early recognition and clinical diagnosis.

Key words: Floor of the mouth, swellings, salivary gland disorders, tumors, reactive conditions, developmental/ congenital conditions, foreign body.

Classification

3. Developmental/ Congenital conditions Dermoid cyst

1. Tumors a.

Epidermoid cyst

Salivary gland tumors

Teratoid cyst

Benign Tumors

Branchial cyst

Pleomorphic adenoma

Vascular lesions

Monomorphic adenoma

Thyroglossal duct cyst

Malignant tumors

Cystic hygroma

Adenoid cystic carcinoma

Ectopia and hypertrophy of salivary glands

Acinic cell carcinoma

Duplication cyst

Clear cell carcinoma

Congenital imperforate submandibular duct

Mucoepidermoid carcinoma 4. Infections b.

Mesenchymal and other tumors

a.

Acute Ludwig's angina

b.

Chronic

Lipoma Myxoma Neurilemoma

Tuberculosis

Leiomyoma Neurofibroma

5. Miscellaneous Foreign body

Rhabdomyoma

2. Reactive conditions Sailolithiasis Ranula

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Amyloidosis

Introduction Development of the Floor of the mouth takes form as early as in the fourth week of gestation with the downward growth and subsequent degeneration of the

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Manjunath N, Mahesh M.S

ectoderm surrounding the peripheral of the tongue, forming the lingual sulcus separating the tongue and the floor of the mouth. The anterior boundary is demarcated in the sixth week with the formation of the Merkel's cartilage, which later ossifies to form the mandible. At about this point in the fetal development, focal thickenings appear in the oral epithelium. These foci proliferate into the underlying ectomesenchyme to form buds which then morphogenise and cytodifferentiate to form the salivary gland. The formation of these structures entwine with a network of nerve, blood vessels and lymphatic system forming the bulk of the floor of the mouth.

The floor of the mouth presents a variety of swellings; some may lead to serious manifestations while others may persistently hamper the quality of life. Since the dentist will most often be the first to observe these conditions, it is essential that he or she be familiar with their diagnosis. This article will help the clinician in making a correct and early diagnosis of not only the common conditions but also some of the rare ones.

Though there have been some classifications for swellings of the floor of the mouth mentioned,1-4 the fact that a large number of conditions involve the floor of the mouth makes it difficult to develop a uniform system. An attempt is made to classify and describe the clinical presentation of the various common and uncommon conditions.

Tumors a. Salivary gland tumors: Benign and malignant tumors Takahashi et al in a study of 200 cases of minor salivary gland tumors found that 63.5% are benign, represented by pleomorphic adenomas and monomorphic adenomas, while 36.5% are malignant tumors, represented by adenoid cystic carcinoma, mucoepidermoid carcinoma, acinic cell carcinoma and clear cell carcinoma. These minor salivary gland tumors are more commonly seen in females in 5th and 6th decade of life. Seventeen percent of all salivary gland tumors are located in the gingiva, floor of the mouth and tongue and all these are predominantly malignant.5 The tumors begin as slow growing, asymptomatic, submucosal masses, but may ulcerate in the later stages. Although the lesions can be histologically different, they cannot be distinguished clinically.6 b. Mesenchymal and other tumors: Lipoma - Lipoma is a benign mesenchymal neoplasm composed of mature adipocytes, usually surrounded by a thin fibrous capsule.7 They are the most common soft tissue tumor but only 1% to 4% of cases involve the oral

cavity. Oral lipomas usually present as painless, wellcircumscribed, slow-growing submucosal or superficial lesions affecting predominantly the buccal mucosa, floor of the mouth and tongue.7,8 Generally, oral lipomas have been reported to occur in all ages but are frequently seen after 40 years of age with a slight male predominance.9,10 Majority of the oral lipomas rarely grow greater than 2.5cm in diameter. Histologically, lipomas can be classified as simple lipomas or its variants namely fibrolipomas, spindle cell lipomas, intramuscular or infiltrating lipomas, angiolipomas, salivary gland lipoma, pleomorphic lipomas, myxoid lipomas and atypical lipomas. Although the clinical appearance of colour and tissue consistency may vary with the combination of histologic features, such combinations are not of prognostic significance. The treatment of oral lipomas, including all the histologic variants, is simple surgical excision. No recurrence is observed7 but rarely transforms into liposarcoma a malignant counterpart.

Myxoma - Myxoma is a benign tumor of mesenchymal origin. It is extremely rare in the oral mucosa and most of the lesions represent myxoid degeneration of the connective tissue and not a true neoplasm. Clinically, the myxoma is a well-defined mobile tumor covered by normal epithelium and soft on palpation. It may appear at any age and is most frequent on the buccal mucosa, floor of the mouth and palate. The diagnosis is established by histopathologic examination. Immunohistochemical markers are useful to distinguish nerve sheath myxomas from other oral myxoid lesions. Treatment is surgical excision.11 Neurilemmoma - Neurilemmoma or Schwannoma is a benign, slow growing and encapsulated tumour originating from Schwann cells.12 Clinically it appears as a solitary well-circumscribed firm and sessile nodule, usually covered by normal epithelium. It is painless, fairly firm on palpation and varies in size. It may occur at any age and is commonly located on the tongue and occasionally in the floor of the mouth. Histopathologic examination is essential to establish the diagnosis.

Treatment is surgical excision.11 Leiomyoma - Leiomyoma is a rare benign tumor from the smooth muscles. In the mouth it derives from the smooth muscles of blood vessel walls and from the circumvallate papillae of the tongue. Oral leiomyomas affects both the sexes equally and usually persons more than 30yrs of age. Clinically it appears as a slow growing, painless, firm and well defined tumor with normal or reddish color. The tumor is movable and fairly soft on palpation.11 The common location is the tongue and occasionally the floor of the mouth.13 The diagnosis is established by histopathologic examination and the treatment of choice is surgical excision.

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Differential diagnosis of swellings In the floor of the mouth

Neurofibroma - Although the neurofibroma may be a solitary lesion, more often it is part of the neurofibromatosis of von Recklinghausen's disease.

Clinically, it usually appears as a painless well-defined pedunculated firm tumor, covered by normal epithelium.

Neurofibromas vary in size from several millimeters to several centimeters. The lesion commonly involves buccal mucosa occasionally the floor of the mouth.

Diagnosis is by histopathologic examination and surgical excision is the treatment.11 Rhabdomyoma - Rhabdomyomas are rare benign mesenchymal tumors composed of striated muscle cells and distinguished in cardiac and extracardiac localizations. Extracardiac type may be classified as fetal and adult type. Adult rhabdomyoma is an asymptomatic, well defined submucosal solitary mass, that can grow to many centimeters before discovery and it may be multifocal and deeply located. The most frequent oral sites are floor of the mouth, soft palate and base of the tongue. It presents at a mean age of 50 years and occur predominantly in males than in females. Diagnosis is by histopathology and complete excision is the treatment.14,15

Reactive conditions Sialolithiasis - Sialolithiasis is the most common disease of salivary glands. It is estimated that it affects 12 in 1000 of the adult population.16 Males are affected twice as much as females.17 80% of sialoliths occur in the submandibular gland or its duct. Submandibular sialolithiasis is more common as its saliva is (i) more alkaline, (ii) has an increased concentration of calcium and phosphate, and (iii) has a higher mucous content than saliva of the parotid and sublingual glands. In addition, the submandibular duct is longer and the gland has an antigravity flow.16 A firm, non-tender swelling in the anterior floor of the mouth in the region of the submandibular duct, pain and swelling of the concerned gland at mealtimes and in response to other salivary stimuli are significant.

Bimanual palpation of the floor of the mouth, in a posterior to anterior direction, reveals a palpable stone in a large number of cases of submandibular sailolithiasis.

Occlusal radiographs are useful in showing radiopaque stones. About 20% of submandibular gland sailoliths are radiolucent and sailography may be required to locate them.17 Sialolithiasis is treated using sialogogues to promote saliva production and flush the stone out of the duct. With gland swelling and sialolithiasis, infection should be assumed and a penicillinase resistant anti staphylococcal antibiotic prescribed. Most stones will respond to such a regimen, combined with simple sialolithotomy when required. Almost half of the submandibular calculi lie in the distal third of the duct and are amenable to simple surgical release through an incision in the floor of the mouth, which is relatively simple to perform and not usually associated with

22

complications. If the stone is sufficiently forward it can be milked and manipulated through the duct orifice. If the gland has been damaged by recurrent infection and fibrosis, or calculi have formed within the gland, it may require removal.18 Ranula - Ranula is defined as a mucous extravasation from a traumatized sublingual gland or duct into the soft tissues of the floor of the mouth above the mylohyoid muscle.19 The term 'ranula' is used because this condition often resembles the swollen abdomen of a frog.20 Plunging ranula may occur with cervical extension through the mylohyoid muscle.21 Ranula usually occurs in children and young adults, with the peak frequency in the second decade. There is a slight female predilection.

The condition most commonly presents as a painless, slow growing, soft and movable mass in the floor of the mouth. Superficial ranula can have a typical bluish hue, but when it is deeply seated, the mucosa may have a normal appearance. If large may deviate the tongue, affect swallowing, speech, mastication, or respiratory function. Several treatment methods have been advocated to eradicate ranulas but excision of the ranula with sublingual gland is the most reliable treatment method which will not result in recurrence because saliva producing tissues no longer exist.20, 22

Developmental/ Congenital conditions: Dermoid cyst, epidermoid cyst and teratoid cyst Dermoid cysts form during embryonic development either via sequestration of ectodermal tissue or via failure of the ectoderm to separate from the mesoderm, usually between week 3 and week 5 of gestation. 23 About 7% of all dermoid cysts arise in the head and neck; among them, 23% are located at the floor of the mouth. Histologically, they can be further classified as epidermoid, dermoid or teratoid.2,24 The simple type is epidermoid in which the cyst wall is lined by stratified squamous epithelium, which may be partly keratinized.

The compound dermoid type is similar to the epidermoid but the epithelial lining and wall shows evidence of skin appendages. The third and rarest is the teratoid type which contains mesodermal tissue derivatives, such as muscle in addition to adnexal structures. Among three, epidermoid cysts are said to be most common and teratoid cysts least common.25 Dermoid cysts are more common in the second and third decades of life with a significant male predilection.26,27 It often occurs in the floor of the mouth, originating either deep or superficial to the mylohyoid muscle. It is a painless, well encapsulated, slow-growing cyst of doughy consistency. A fine needle aspiration may often yield keratinous, caseous, sebaceous, hair follicles and cartilage. Dermoid cysts have been classified as median and lateral. The two differ in their origin and clinical

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Manjunath N, Mahesh M.S

presentation. The median cyst lies in the connective tissue beneath the lingual frenum. As they increase in size, they push apart the genioglossus muscle, growing deeper into the floor of the mouth and backwards into the tongue.

Whereas lateral dermoid cyst lies in the depth of the muscular gutter formed by the mylohyoid muscle laterally, and the genioglossus and geniohyoid muscle medially. However, when these cysts reach large sizes, it becomes difficult to differentiate between median and lateral types. Diagnostic imaging includes CT, MRI and ultrasonography. The use of plain film radiographs may not be so useful unless a radiopaque medium is injected into the cyst. Excision of the dermoid cyst is the treatment of choice.3,26 Branchial cyst - Branchial cysts or Lymphoepithelial cysts are developmental, but their pathogenesis is unknown. The classical explanation is that they are derived from remnants of the branchial arches or clefts.

This has been disputed, and it is likely that most arise from epithelium, possibly of tonsillar or salivary origin, that becomes entrapped by lymphoid tissue (Bhaskar's enclavement theory).28,29 Branchial cysts typically present as a unilateral, fluctuant soft tissue swelling that is localized deep to the upper third of the anterior border of sternocleidomastoid of the neck. Oral lymphoepithelial cysts are commonly seen in the floor of the mouth (60%) and the tongue. They are predominantly seen in males with a mean age of 32.6 years, measuring 0.3 cm to 1.5 cm in size, yellowish-white in colour, freely movable, with duration of few months to many years. Complete excision is the treatment.30 Vascular lesions - Mulliken and Glowacki31 classified vascular lesions into; hemangiomas and vascular malformations. Vascular malformations are further classified into capillary, venular (port wine stains), venous, lymphatic or mixed (arteriovenous or venouslymphatic) malformations. Hemangiomas are the most common tumors of the head and neck region in infants and children. They typically present at birth, enlarge during the first year of life, and then usually spontaneously involute by 5 years of age. For this reason, treatment is often unnecessary. The classification proposed by Mulliken and Glowacki suggests that the term hemangioma can be reserved for lesions with cellular proliferation that present in infancy and usually involute by adolescence. Of the lesions restricted to the oral cavity, the tongue and floor of the mouth are the usual sites. These vascular lesions present as a distinctly reddish, purplish or bluish lesion that blanches when compressed. The latter characteristic is useful in distinguishing it from pigmented nonvascular lesions. It has an elevated, sessile appearance and overlying mucosa is smooth and hypervascular in some areas and pebbly in others. Sometimes it may cause dysphagia and dysarthria. Small lesions may require no treatment

but those causing functional problems or that are at risk of injury and causing profuse bleeding, require surgical management.6,32 Thyroglossal duct cyst - Thyroglossal duct cyst is the most common non-odontogenic cyst in the neck, accounting for 70% of congenital neck abnormalities.33,34 It results from retention of the epithelial tract between the thyroid gland and its origin, the foramen ceacum.

Thyroglossal duct cyst is most often associated with young age, two thirds of cases presenting in the first decade of life. The classic description of the lesion is that of a painless swelling in a young child along the midline of the neck which rises with deglutition or tongue protrusion. The lesion is compressible and may fluctuate in size. If, however, it is entwined with the hyoid bone, it may not display any movement with tongue protrusion or swallowing. Rarely when it presents in the floor of the mouth and the base of the tongue, it will be an extension of the neck mass. Usually asymptomatic but when it is large it may cause dysphagia and pain. Surgical removal is the treatment.35 Cystic hygroma - Cystic hygromas are large lymphangiomas that are most often found in the posterior triangle of the neck and the axilla in children. They are most frequently found before age 2 and may be massive.

In the oral cavity the common locations are tongue, floor of the mouth and salivary glands. The superficial lesions are papillomatous in nature and may have a relatively normal mucosal covering or reddish to purple hue. The deeper lesions are diffuse and appear as grapelike structures covered by normal mucosa.6 The diagnosis can usually be made by history and physical examination and confirmed by biopsy. Treatment is by surgical excision of small lesions and staged debulking excisions in more severe cases.36 Ectopia and hypertrophy of salivary glands Congenital absence of the salivary glands is infrequent and more often involves multiple major salivary glands.

At times the submandibular salivary gland may be absent in its usual location and present as a swelling in the floor of the mouth. This represents an ectopically positioned submandibular gland. It can be confirmed by ultrasound and sialography.37 Occasionally, unilateral aplasia of submandibular salivary gland may present with hypertrophy of ipsilateral sublingual salivary gland.

Salivary gland aplasia may be associated with first branchial arch defects in the Treacher-Collins syndrome (mandibulofacial dysostosis) or orbital abnormalities like lacrimal hypoplasia, canalicular atresia, and absence of the lacrimal puncta. Absence of salivary glands may also be seen as part of the lacrimo-auriculo-dento-digital syndrome, characterized by hypoplasia, aplasia or atresia of the lacrimal system, deafness and ear malformations, and dental and digital anomalies. These patients may be completely asymptomatic or have dysphagia and dryness.

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Differential diagnosis of swellings In the floor of the mouth

Compensatory sublingual salivary gland hypertrophy may be confirmed by using a combination of CT and MRI.38 Congenital imperforate submandibular duct Congenital cystic swelling in relation to submandibular duct may arise rarely in a newborn due to imperforate submandibular duct opening, atresia or duplication anomaly of Wharton's duct. Failure of canalization of the terminal end of the duct has been cited as the cause of this anomaly.39 Mostly reported cases have been unilateral swellings manifesting at birth. Diagnosis is made primarily by physical examination, rarely magnetic resonance imaging is required to outline ductal anatomy to diagnose duplication anomaly. Treatment includes simple incision and decompression of cyst, marsupialisation with or without ductoplasty or excision of duplication anomalies.4 Duplication cyst - Enteric duplication cysts are cystic lesions containing a gastrointestinal mucosal lining. Some consist of only a mucosal lining, and others have a multilayered wall of mucosa, submucosa, and muscularis propria. These duplication cysts are common in male newborns. They occur anywhere from the oral cavity to the rectum rarely in the oral cavity involving the tongue and the floor of the mouth. Most present asymptomatically, but the location of these lesions has the potential to cause respiratory and feeding difficulties. An MRI study is a recommended part of the preoperative evaluation but cannot be relied on for definitive diagnosis because these lesions appear similar to dermoid cyst. Aspiration alone results in recurrence, and the functional mucosa continues to secrete mucus if left intact.

Also, there is a risk of ulceration and bleeding in the presence of acid-secreting gastric mucosa. Complete cyst excision with removal of the mucosal lining is the treatment of choice with no recurrence.40

Infections Acute: Ludwig's angina - Ludwig's angina is a rapidly spreading, indurated, bilateral cellulitis that begins in the floor of the mouth and involves both the submandibular and sublingual spaces.41 The primary site of infection is odontogenic in 70% to 80% of cases.42 The second and third molars are most frequently involved, because their roots extend below the level of the mylohyoid muscle, thus crossing both the sublingual and submandibular spaces. The majority of the patients are adults who have no significant comorbidities, but this condition has also been associated with systemic diseases, such as chronic glomerulonephritis, systemic lupus erythematosus, aplastic anemia, neutropenia, immunodeficiency (eg, HIV infection), diabetes mellitus, and hypersensitivity. Pain in the floor of the mouth and anterior neck, dysphagia, odynophagia, and respiratory distress are common symptoms. Clinical findings include

24

fever, tachypnea, tachycardia and fetid breath. Inspection of the malodorous oral cavity is limited because of trismus, but a firm, raised floor of the mouth may be evident.

Diagnosis is based on clinical findings, although contrastenhanced CT can help determine the extent of the infection, especially in the presence of an abscess.

Complications of Ludwig's angina include sepsis, pneumonia, asphyxia, empyema, pericarditis, mediastinitis, and pneumothorax. Treatments include airway management by tracheostomy and empiric antibiotic therapy with IV penicillin G, clindamycin, or metronidazole is recommended before culture and antibiogram results are available.43 If an abscess is present, the definitive treatment would be incision and drainage.

Chronic: Tuberculosis - Tuberculous involvement of oral cavity is an extremely rare development, even in populations with high incidence of pulmonary disease.44 They may be either primary or secondary in occurrence, most being secondary. Oral tuberculosis may occur at any location on the oral mucous membrane, but the tongue is most commonly affected. Other sites include the palate, lips, buccal mucosa, gingiva, palatine tonsil and floor of the mouth. The oral lesions may present in a variety of forms, such as ulcers, nodules, tuberculomas and periapical granulomas.45,46 The diagnosis of tuberculosis is confirmed by the presence of acid-fast bacilli in the specimen, or more likely by culture of tuberculous bacilli. Since oral tuberculosis is almost always secondary to pulmonary tuberculosis, sputum culture must also be carried out. Radiographic evidence of tuberculosis must also be sought.47 All patients should receive prompt anti-tuberculosis therapy.48

Miscellaneous Foreign body - Foreign bodies embedded in the oral cavity are infrequently reported in the literature because such bodies are most commonly lodged superficially and are easily removed by the patient or parents in the case of a child or by the general practitioner. Thus, it is rather rare, especially in the pediatric age group, that a foreign body is totally embedded in the floor of the mouth and presents as a mass.49 Reported foreign bodies include fish bones, metal objects, broken tooth fragments, pen cap and projectiles of an air rifle. Thus, the possibility of a foreign body should not be underestimated when evaluating a child with swelling in the floor of the mouth.

Amyloidosis- Amyloidosis is a rare disease characterized by the deposition of an insoluble extracellular fibrillar protein in various tissues of the body.50 Amyloidosis of floor of the mouth and submandibular salivary gland is very rare.51 Generally, peak age incidence is in the fifties,

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Manjunath N, Mahesh M.S

with a male: female ratio of 2:1. The amyloid infiltration can give rise to difficulty in chewing and swallowing.

These patients often are anxious ill-looking with an open mouth posture and "hot potato" speech. The disease is rapidly fatal within 1 3 years of diagnosis. Diagnosis has remained mostly at autopsy. It remains one of the challenging diseases facing the clinician and pathologist as its etiology and pathogenesis have remained elusive and speculative and its management, controversial. To date, no single treatment has been shown to alter the underlying pathology or disease progression.

Discussion The history related by the patient is often the single most significant factor in determining the diagnosis. The patient's age, chief complaint, the duration of the swelling, location and physical characteristics of the swelling and any positive medical history are all important aspects of information that can help determine the nature of the condition. From the clinical stand point, as a general dentist one is expected to diagnose the swelling provisionally. It should be remembered that conventional plain film radiographs are of no value except in the diagnosis of sialolithiasis. Fine needle aspiration and ultrasonography may be performed to differentiate fluid filled cysts from a solid tumor.

However, fine needle aspiration may be performed chair side to differentiate a ranula from a dermoid cyst more reliably. CT and MRI is more valuable in determining the extent and plan the treatment rather than in the diagnosis of the condition.

In case of tumors a definitive diagnosis cannot be established on the basis of above described modalities for which a histopathological examination of a biopsy specimen is essential. This is particularly important when there is a possibility that the swelling may be malignant.

The definitive diagnosis of these tumors is essential in determining the treatment and prognosis.

demographic and histologic study of 200 cases.

Tohoku J exp med. 1990;161(2):111-128.

6. Daniel ML, James AG, Eric TR. Differential diagnosis of tongue lesions. Quintessence International 2003;3(3):15-26.

7. Fregnani ER, Pires FR, Falzoni R, Lopes MA, Vargas PA. Lipomas of oral cavity: clinical findings, histological classification and proliferative activity of 46 cases. Int J Oral Maxillofac Surg 2003;32(1):49-53.

8. Weiss SW, Goldblum JR. Benign lipomatous tumors.

In: Enzinger and Weiss's soft tissue tumors. 4th ed. St. Louis: Mosby; 2001:571-639.

9. Furlong MA, Fanburg-Smith JC, Childers EL. Lipoma of the oral and maxillofacial region: site and subclassification of 125 cases. Oral Surg Oral Med Oral Pathol 2004;98(4):441-50.

10. Epivatianos A, Markopoulos AK, Papanayotou P. Benign tumors of adipose tissue of the oral cavity: a clinicopathologic study of 13 cases. J Oral Maxillofac Surg 2000;58(10):1113-1117.

11. Laskaris G. Color atlas of oral diseases. New York; Thieme Medical Pub.;2003:310-312.

12. Hazarika P, Nooruddin SM, Nayak RG. Neurilemoma of the floor of the mouth: a case report.

J Indian Dent Assoc 1983;55:325-326.

13. Chuan HU, Tung CT, Hsin MC, Chun PC. Oral Leiomyoma-case report. J dent sciences 2005/06;24(2):114-120.

14. Favio G, Lo Muzio L, Serico R, Maiorano E. Rhabdomyoma of the head and neck: clinicopathologic features of two cases. Head and Neck 2003;25:700-4.

15. Roberts F, Kirk AJB, More IAR, Butler J, Reid RP. Oesophageal rhabdomyoma. J Clin Pathol 2000;53:554-7.

References

16. Leung AK, Choi MC, Wagner GA. Multiple sialoliths and a sialolith of unusual size in the submandibular duct. Oral Surg Oral Med Oral Pathol 1999;87:331-333.

1. Tan MS, Singh B. Difficulties in diagnosing lesions in the floor of the mouth Report of two rare cases.

Ann Acad Med Singapore 2004;33 (suppl):72S-76S.

17. Cawson RA, Odell E W. Essentials of oral pathology and oral medicine. 6th ed. Edinburgh, Churchill Livingstone; 1998: 239-240.

2. Bruno CJ, Gabriela VD, Andre CJ, Cassio RS: Epidermoid cyst of the floor of the mouth-A case report: J Canad dent assoc 2007;73(6):525-528.

18. Siddiqui SJ. Sialolithiasis: an usually large submandibular salivary stone. Br dent J 2002;193(2):89-91.

3. Swaify GA, Gharib MO, Dhanrajani PJ. Dermoid cyst of the floor of the mouth. Saudi Dent J 1991;3(1):21-23.

19. Galloway RH, Gross DP, Thompson SH et al.

Pathogenesis and treatment of ranula: Report of three cases. J Oral Maxillofac Surg 1989;47:299.

4. Kamalesh P, Adel MA. Congenital imperforate submandibular duct in a newborn. Indian J pediatrics 2007;74:687-688.

20. Greenberg MS, Glick M. Burket's Oral Medicine diagnosis & treatment. 10th ed. BC Decker: Elsevier; 2005: 247.

5. Takahashi H, Fujita S, Tsuda N, Tezuka F, Okabe H. Intraoral minor salivary gland tumors: A

21. Araki H. An experimental study of oral mucous cyst formation. Japan J Oral Maxillofac Surg 1987;33:467.

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22. Ghassan D., Yasser A., Ramaraj R. Ranula and the Sublingual Salivary Glands; Review of 32 Cases.

Bahrain Med Bull 1998;20(1):3-4.

23. Mathews J, Lancaster J, O'Sullivan G. True lateral dermoid cyst of the floor of the mouth. J Laryngol Otol 2001;115:333-335.

24. King RC, Smith BR, Burk JL. Dermoid cyst in the floor of the mouth; review of the literature and case reports. Oral Surg Oral Med Oral Pathol 1994;78:567-576.

floor of the mouth. J of Laryngol Otol 2005;119(11):928-930.

38. Srinivasan A, Moyer JS, Mukherji SK. Unilateral submandibular gland aplasia associated with ipsilateral sublingual gland hypertrophy. Am J Neuroradiol 2006; 27:2214-16.

39. Amin MA, Bailey BM. Congenital atresia of the submandibular duct: a report of 2 cases and review.

Br J Oral Maxillofac Surg 2001;39(6):480-482.

25. Yilmaz I, Yilmazer C, Yavuz H, Bal N, Ozluoglu LN. Giant sublingual epidermoid cyst; a report of two cases. J Laryngol Otol 2006;120(3):E19.

40. Debbie E, Kathleen B, Charles T, Timothy B, Michael JB. Congenital foregut duplication cysts of the anterior tongue. Arch Otolaryngol Head Neck Surg 2001; 127:1484-1487.

26. Seah TE, Sufyan W, Singh B. Case report of a dermoid cyst at the floor of the mouth. Ann Acad Med Singapore 2004;33(suppl):77S-79S.

41. Srirompotong S, Art-smart T. Ludwig's angina: a clinical review. Eur Arch Otorhinolaryngol 2003;260:401-403.

27. Longo F, Maremonti P, Mangone GM, De Maria G, Califano L. Midine (dermoid) cysts of the floor of the mouth; report of 16 cases and review of surgical techniques. Plast Reconstr Surg 2003;112(6):1560-1565.

42. Hamza NS, Farrel J, Strauss M. Deep facial space infection of the neck: a continuing challenge. South Med J. 2003;96:928-932.

28. Kumara GR, Gillgrass TJ, Bridgman JB. A lymphoepithelial cyst (branchial cyst) in the floor of the mouth. N Z Dent J 1995;91:14-15.

43. Jimenez Y, Bagan JV, Murillo J. Odontogenic infections, complications and systemic manifestations. Med Oral Pathol Oral Cir Bucal 2004;9(suppl):143-147.

29. Bhaskar SN. Lymphoepithelial cysts of the oral cavity. Report of twenty four cases. Oral Surg Oral Med Oral Pathol 1966;21:120-128.

44. Komer H, Shaefer RF, Mahoney PL. Bilateral tuberculosis granulomas of the tongue. Arch Otolaryngol 1965;82:649.

30. Suzuki H, Baba S, Hashimoto K. Lymphoepithelial cyst in the sublingual region; Report of a case and review of literature. Oral Med Pathol 2000;5:105-108.

45. Shafer WG, Hine MK, Levy MB. A textbook of Oral Pathology. Philadelphia: WB Saunders; 1983: 340-440.

31. Mulliken JB, Glowacki J. Haemangiomas and vascular malformations in infants and children: a classification based on endothelial characteristics.

Plast Reconstr Surg 1982;69:412.

32. Theognosia SC, Chariton EP, Adam AH, George AV. Arteriovenous malformation of the floor of the mouth: a case report. Eur Arch Otorhinolaryngol 2005;262:939-942.

33. Allard RHB. The thyroglossal cyst. Head Neck Surg 1982;5:134-146.

34. Montgomery WW. Surgery of the upper respiratory system. Philadelphia: Lea and Febiger; 1973: 80.

35. Angel DH, Alberto L, Sanjuanita F. Atypical presentation of thyroglossal duct cyst in the floor of the mouth. Rev Med Hosp Gen Mex 2004;67(3):146-148.

36. Osborne TE, Haller JA, Levin LS, Little BJ, King KE. Submandibular cystic hygroma resembling a plunging ranula in a neonate: review and report of a case. Oral Surg Oral Med Oral Pathol 1991;71(1):16-20.

37. Barlow ST, Drage NA, Thomas DW. Ectopic submandibular gland presenting as a swelling in the

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46. Dimitrakupoulas I, Zouloumis L, Lazaridis N, Karakasis D, Trigonidis G, Sichletidis L. Primary tuberculosis of the oral cavity. Oral Surg Oral Oral Med Oral Pathol 1991;72:712-715.

47. Von Arx DP, Husain A. Oral Tuberculosis. Br dent J 2001;190(8):420-422.

48. Ramakant D, Sidharth S, Paras N. Tuberculosis of oral cavity. Indian J Tuberc 2008;55:51-53.

49. Zafer UM, Cagdas KA, Nezahat E, Veli A. An unusual foreign body in the floor of the mouth presenting as a gradually growing mass. Eur Arch Otorhinolaryngol 2005;262:875-877.

50. Simpson GT 2nd, Skinner M, Strong MS, Cohen AS. Localised Amyloidosis of the head and neck and upper aerodigestive/lower respiratory tracts. Ann Otol Rhinol Laryngol 1984;93:374-379.

51. Daniel DK, Titus SI, Clement AO, Aliyu MK, James AF, Onyekwere GB, Effiong EU. Amyloid angiopathy of the floor of the mouth: a case report and review of the literature. J Med Case Reports 2007;1:117-120.

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Review article

Methods of predicting favorable mandibular growth rotations in growing patients - An Overview Vincy Antony1, Prathapan Parayaruthottam2 1.Reader, Dept. of Orthodontics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala.

2. Assistant Professor, Dept of Orthodontics, Govt. Dental College, Kozhikode, Kerala Correspondence: Vincy Antony, Reader, Dept. of Orthodontics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala. e-mail: vincyantony2008@yahoo.com

Abstract: Growth modification in developing skeletal malrelations is gaining popularity among dental professionals.

This is because an unfavorable face leads to psychological trauma of patients and parents in our present day society, which gives a lot of importance to external looks. This in turn leads them to request treatment at an earlier age where growth modifications are possible. Success of growth modification procedures entirely depends on a favorable growth. Prediction of favorable growth is the most difficult process as variability is the only constant in a living organism. Prediction of favorable growth rotations in mandible in cases indicated for growth modification procedures is absolutely essential.

Keywords: Growth modification, Growth prediction, Jaw rotation.

At the time when X-ray cephalometry was introduced, research was concerned primarily with the average growth changes in form of the head and face.1 Intermaxillary relation was then considered as being static throughout the period of growth. The treatment of malocclusion, therefore, was thought to be essentially independent of age, sex, or maturation rate.

This view of the facial development is perhaps one of the main reasons that, in spite of the introduction of highly efficient appliance systems in treatment, due regard has not always been given to the individual variability of growth,2 which applies to both fixed and removable appliances. As a result of longitudinal studies in which X-ray cephalometry was applied, it was recognized that there are considerable individual differences in the development of facial form and in intermaxillary relations. It was further realized that the individual growth changes in shape are the rule rather than the exception.

Growth prediction methods for predicting favorable growth rotations in mandible discussed here include 1. Longitudinal, 2. Metric, 3. Structural signs of Bjork, 4. Morphology of mandible by Petrovic, 5. Rotation of jaw bases according to Lavergne and Gasson and Stutzmann's angle.

These are the few commonly used methods but not the end

of the list for an interested reader. A brief review of these methods is the aim of this article.

Prediction by the longitudinal method,3 which is commonly used, consists of following the course of development in annual x-ray cephalometric films. In some cases, treatment may have to be started early and the direction of growth accessed by superimposing radiographs taken at different intervals rather than wait till the set pattern of growth is diagnosed. The longitudinal method has a general limitation in that the pattern of growth is not constant and the pattern recorded at a juvenile age may well have changed by adolescence.

Another limitation of the longitudinal method is that, whereas it permits the observation of changes in the sagittal jaw relation with growth, those changes occurring in the vertical jaw relation are, to a large extent, masked.

The metric method3 aims at a prediction of facial development on the basis of the facial morphology, determined metrically from a single x-ray film. Statistical models and cephalometric analyses are used for the metric method. A more advanced form of this method is computerized prediction of growth. It is known that, on the average, mandibular prognathism increases with age and that the range of variation is large. Individually, there may be a very large increase, but occasionally even a decrease is seen. A harmonic sagittal jaw relation may thus develop into a disharmonic one, and vice versa.

When predicting vertical development of the face also the metric method has not proved more suitable. As determined from its lower border, the mandible on the

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Methods of predicting favorable mandibular growth rotations in growing patients - An Overview

average rotates forward a little during adolescence, and its inclination thus decreases. Individually, this decrease may be extremely pronounced, but occasionally there may even be an increase in the inclination.

The structural method3 is based on information concerning the remodeling processes of the mandible during growth, gained from the implant studies. The principle is to recognize specific structural features that develop as a result of the remodeling in a particular type of mandibular rotation.4 Prediction of the subsequent course is then made on the assumption that the trend will continue.

From the viewpoint of growth, the mandible may be regarded as a more or less unconstrained bone, for it may change its inclination in several ways. A critical factor in this respect is the site of the center of rotation, which may be located at the posterior or anterior ends of the bone or somewhere in between, in which case the ends of the mandible swing in different directions. Thus there may be forward or backward rotation of mandible.

Structural signs of growth rotation From the clinical standpoint it is important to detect extreme types of mandibular rotation occurring during growth. Seven structural signs of extreme growth rotation will be considered in relation to the condylar growth direction. Not all of them will be found in a particular individual, but the greater the number that is present, the more reliable the prediction will be.

Moreover, it is evident that these signs are not so clearly developed before puberty.

The seven signs are related to the following features: 1. Inclination of the condylar head, 2. Curvature of the mandibular canal, 3. Shape of the lower border of the mandible, 4. Inclination of the symphysis, 5. Interincisal angle, 6. Interpremolar or intermolar angles and 7. Anterior lower face height.

In forward growing mandible (Fig. A, C, E), condyle is upright compared to a backward growing mandible (Fig. B, D, F) in which it is inclined backward, but it may not be easy to identify on the cephalometric radiograph, where part of the condyle is masked, as is seen in the Fig. A and B. The curving of the mandibular canal may also be a clear sign. In the vertical type of condylar growth (Fig. B), the curvature of the canal tends to be greater than that of the mandibular contour, including the angle of the jaw, whereas in the sagittal type (Fig. A) the opposite is generally the case. The canal may then be straight or, in pathologic cases, it may even curve in the opposite direction.

28

The shape of the lower border of the mandible is highly characteristic. In vertical condylar growth (Fig. D, F), the pronounced apposition below the symphysis and the anterior part of the mandible produces an anterior rounding, with a thick cortical layer, while the resorption at the angle produces a typical concavity. In sagittal growth (Fig. C, E), the anterior rounding is absent and the cortical layer is thin, while the lower contour at the jaw angle is convex.

The inclination of the symphysis is an important feature. In the vertical type of growth, the symphysis swings forward in the face and the chin is prominent, while in the sagittal type it is swung back, with a receding chin. The evaluation is complicated by the simultaneous remodeling of the alveolar process in the opposite direction, as is exemplified by the cranium with the openbite.

The difference in the interincisal angle is evident (Fig. G), in spite of the compensatory tipping of the lower incisors.

The difference in the interpremolar and intermolar angles in the two growth types is also clear (Fig.H) A compression or overdevelopment of the lower face is likewise typical. In the living subject there is a difference in the posture of the lips.

Rotations of jaw bases were classified according to Lavergne and Gasson5 in 1982, as: i. Convergent, ii.

Divergent, iii. Cranial, and iv. Caudal. Convergent rotation is difficult to manage using functional appliances and severe divergent rotation may need orthognathic surgery.

Morphology of mandible6 was classified by Petrovic as, i. Orthognathic, ii. Prognathic, and iii.

Retrognathic. Prognathic mandible grows horizontally and retrognathic mandible grows vertically.

Stutzmann6 in 1976 found that growth direction of the condyles coincide in general with the arc of individual trabeculae, located just inferior to the central part of condylar cartilage.

Summary A very brief outline of prediction of mandibular growth rotations has been done here. Detailed description of each method and an exhaustive coverage of all methods is not the intention here. Detailed review of literature is necessary for the same.

References 1.

Bjรถrk A. The face in profile; an anthropological xray investigation on Swedish children and conscripts. Svensk tandl. tidskr. 1947;40(Supp. 5B).

2.

J. M. H. Dibbets. The puzzle of growth rotation,

JOURNAL OF DENTOFACIAL SCIENCES AND RESEARCH 2011; 1(1):27-30.

Vincy Antony, Prathapan Parayaruthottam

American Journal of Orthodontics. Jun 1985;87(6):473-480.

3.

4.

Bjork A. Prediction of mandibular growth rotation.

American Journal of Orthodontics. Jun 1969;55(6):585-599.

Bjork A. Variations in the growth pattern of the human mandible: Longitudinal radiographic study

by the implant method. J. D. Res. 1963;42:400-411.

5.

Samir E. Bishara. Textbook Of Orthodontics.

W.B.Saunders; 2001.

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Graber, Rakosi and Petrovic. Dentofacial orthopedics with functional appliances. 2nd ed.

Mosby; 1997.

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Methods of predicting favorable mandibular growth rotations in growing patients - An Overview

Pictures

Fig. A

Fig. B

Fig. C

Fig. D

Fig. H

Fig. E

A

Fig. F

B

C

Fig. G

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Review article

Regenerative endodontics - A review 1

Biji Balan

1.Reader, Dept of Conservative Dentistry and Endodontics, Kannur Dental College, Anjarakandy, Kannur, Kerala.

Correspondence: Biji Balan, Reader, Dept of Conservative dentistry and Endodontics, Kannur Dental College, Anjarakandy, Kannur, Kerala. e-mail : docbiji@gmail.com

Abstract Millions of teeth are saved each year by root canal therapy. Although current treatment modalities offer high levels of success for many conditions, an ideal form of therapy might consist of regenerative approaches in which diseased or necrotic pulp tissues are removed and replaced with healthy pulp tissue to revitalize teeth. Researchers are working toward this objective. Regenerative endodontics is the creation and delivery of tissues to replace diseased, missing, and traumatized pulp. This review provides an overview of regenerative endodontics and its goals, and describes possible techniques that will allow regenerative endodontics to become a reality.

Key words: Tissue engineering, Regenerative endodontics, Stem cell therapy.

Introduction The goal of modern restorative dentistry is to functionally and cosmetically restore the tooth structure. Till recently, a variety of synthetic materials were developed to restore the damaged tooth structure.

Although these materials have proved to be effective, they do not exhibit the same mechanical and physical properties as naturally formed dentin and enamel.

Natural dental hard tissues, i.e. dentin, enamel and cementum exhibit little or no regenerative capability.

Hence, there is a need for the replacement of the tooth tissue.1 Dental caries remain to be one of the most prevalent young adult and childhood diseases, while the phrase “root canal treatment” is probably the most dreaded term in dentistry. There are several ways in which one can potentially engineer lost dentin and the dental pulp. The vitality of the dental pulp may be damaged by infection, exposure, trauma and chemicals. They ultimately result in premature tooth loss and therefore, diminish the quality of life. Regenerative endodontics is the creation and delivery of tissues to replace diseased, missing, and traumatized pulp.

The objectives of regenerative endodontic procedures are to regenerate pulp-like tissue, ideally, the pulp-dentin complex regenerate damaged coronal dentin, such as following a carious exposure and regenerate resorbed root, cervical or apical dentin which can be done with tissue engineering. This review provides an overview of regenerative endodontics and its goals, and describes possible

techniques that will allow regenerative endodontics to become a reality.

According to Langer and Vacanti, tissue engineering is defined as “an inter disciplinary field that applies the principles of engineering and life sciences towards the development of biological substitutes that restore, maintain, or improve tissue function”.2 Tissue engineering is a novel and highly exciting field of research. With tissue engineering techniques, it may be possible to repair damaged tissues or even create replacement organs. Tissue engineering in dentistry can help in the regeneration of enamel and dentin to restore the lost tooth structure in future.

Tissue engineering triad Tissue engineering is the employment of biological therapeutic strategies which are aimed at the replacement, repair, maintenance and/or the enhancement of tissue function.

1. Stem cells / progenitor cells 2. Scaffolds or extracellular matrix 3. Signalling molecules Stem cells are commonly defined as cells that have the ability to continuously divide and produce progenitor cells that differentiate into various other types of cells or tissues. Dental stem cells which were used in the initial tooth tissue engineering studies were obtained from immature, unerupted tooth buds which were isolated from animals like pig, rat etc.

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Regenerative endodontics A review

Types of stem cells 路 Totipotent: Each cell can develop into a new individual e.g. cells from early (1-3 days) embryos. 路 Pluripotent: Cells can form any (over 200) cell types e.g. cells of blastocyst (5-14 days). 路 Multipotent: Cells differentiated, but can form a number of other tissues. e.g. foetal tissue, cord blood, and post natal stem cells including dental pulp stem cells.

Bioengineered Scaffolds The basic role of scaffolds in tissue engineering is to act as carriers for cells, to maintain the space and to create an environment in which the cells can proliferate and produce the desired tissue matrix (Fig.1).

Types of scaffolds 1. Natural scaffolds 2. Mineral scaffolds 3. Synthetic scaffolds 1. Natural scaffolds: The examples for natural scaffolds are collagen, hyaluronic acid, chitosan and chitin. These natural scaffolds have been used in several craniofacial and dental applications. These lack the desired structural rigidity for use in the load bearing region.

by using these three elements (cells, scaffolds and signalling molecules).

Regenerative dentistry including periodontics, endodontics and maxillofacial surgery is a new field that seeks to apply the concepts of tissue engineering to the management of lost oral tissues by using various types of stem cells, growth factors and scaffolds. Within the next 25 years, unparalleled advances in dentistry and endodontics are set to take place, with the availability of artificial teeth, bone, organs and oral tissues.3 Regenerative endodontic procedures can be defined as biologically based procedures which are designed to replace damaged structures including dentin and root structures, as well as the cells of the pulp-dentin complex.4 The factors contributing to the success of regenerative endodontics comprises of the research on adult stem cells, growth factors, organ tissue cultures and tissue engineering material. The objectives of the regenerative endodontic procedures are to regenerate pulp-like tissues: ideally, the dentin pulp complex; regenerated damaged coronal dentin (Fig.3).

Regenerative approaches in endodontics There are several techniques4 for the application of regenerative endodontics which are based on the principles of tissue engineering, such as 1. Root canal revascularization via blood clotting 2. Post natal stem cell therapy

2. Mineral scaffolds: These are composed of calcium phosphates in the form of hydroxyapatite or 尾 tricalcium phosphate. These scaffolds are brittle and hence, are prone to fracture.

3. Pulp implantation

3. Synthetic scaffolds: The most widely used synthetic materials are polymers of polyglycolicacid, polylacticacid and polydioxanone. These scaffolds lack critical cell signalling capabilities and can interfere with new tissue growth.

6. Three dimensional cell printing

Signaling molecules: These are the molecules that transmit signals between cells, functioning as stimulators/inhibitors of growth, as well as the modulators of differentiation. These consist of growth factors (platelet derived growth factor, transforming growth factor - beta), differentiation factors (bone morphogenetic proteins) and stimulating factors.

The Major Approaches To Tissue Engineering Ex-vivo approach: In this technique, the target tissue is created in a laboratory by culturing cells in biodegradable scaffolds in the presence of specific trophic factors before their transplantation into the body.

In-vivo approach: This technique involves the induction of intrinsic healing activity at the site of the tissue defect

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4. Scaffold implantation 5. Injectable scaffold delivery

7. Gene therapy Root canal revascularization via blood clotting: The development of regenerative endodontic procedures may require the re-examination of many of the closely held percepts of traditional endodontic procedures. The revascularization method assumes that the root canal space has been disinfected effectively by the use of intracanal irrigants, with the placement of antibiotics for several weeks. Several case reports have documented the revascularization of the necrotic root canal systems by disinfection, followed by establishing bleeding into the canal system via over instrumentation. There are several advantages to a revascularization approach. First, this approach is technically simple and can be completed using currently available instruments and medicaments without expensive biotechnology. Second, the regeneration of tissue in root canal systems by a patient's own blood cells avoids the possibility of immune rejection and pathogen transmission from replacing the

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Biji Balan

pulp with a tissue engineered construct. An important aspect of these cases is the use of intracanal irrigants (NaOCl and chlorhexdine) with placement of antibiotics (e.g. a mixture of ciprofloxacin, metronidazole, and minocycline paste)for several weeks. This particular combination of antibiotics effectively disinfects root canal system and increased revascularization of avulsed and necrotic teeth suggesting that this is a critical step in revascularisation.5 Post natal stem cell therapy: The simplest method to administer the cells of appropriate regenerative potential is to inject the post natal stem cells into the disinfected root canal systems after the apex is opened. The post natal stem cells can be derived from multiple tissues including skin, buccal mucosa, fat and bone. One recent approach could be to use the stem cells that have been taken from the umbilical cord which are mostly disease and pathogen free.2 Pulp implantation: In pulp implantation, the cultured pulp tissue is transplanted into cleaned and shaped root canal systems. The pulp tissue is grown in sheets in vitro on biodegradable polymer nano fibers or on sheets of extracellular matrix proteins such as collagen I or fibronectin. The limitation of this technique is that specialized procedures may be required to ensure that the cells properly adhere to the root canal walls.6 Scaffold implantation: Pulp stem cells must be organized into a three-dimensional structure that can support cell organization and vascularisation. This can be accomplished by using a porous polymer scaffold which is seeded with pulp stem cells. In pulp-exposed teeth, dentin chips have been found to stimulate reparative dentin bridge formation. Dentin chips may provide a matrix for pulp stem cell attachment and they may also be a reservoir of growth factors. The natural reparative activity of the pulp stem cells in response to the dentin chips provides some support for the use of scaffolds to regenerate the pulp dentin complex.6 Injectable scaffold delivery: Tissue engineered pulp tissue is seeded into the soft three-dimensional scaffold matrix, such as a polymer hydrogel. Hydrogels are injectable scaffolds that can be delivered by syringe, they have the potential to be non-invasive and are easy to deliver into the root canal systems. In theory, the hydrogel may promote pulp regeneration by providing a substrate for cell proliferation and differentiation into an organized tissue structure.5 Despite these advances, hydrogels at are at an early stage of research and this type of delivery system, although promising, has yet to be proven to be functional in vivo.7 Three dimensional cell printing: The three-dimensional cell printing technique can be used to precisely position cells and this method has the potential to create tissue

constructs that mimic the natural tooth pulp tissue structure. The ideal positioning of cells in a tissue engineering construct would include placing odontoblastoid cells around the periphery to maintain and repair dentin, with fibroblasts in the pulp core supporting a network of vascular and nerve cells.8 Gene therapy: Gene therapy has been recently used as a means of delivering genes for growth factors, morphogens, transcription factors and extracellular matrix molecules locally to the somatic cells of individuals, with resulting therapeutic effect. The gene can stimulate or induce a natural biological process by expressing the molecules which are involved in the regenerative response for the tissue of interest.6 Both an in-vivo and ex-vivo approach can be used for gene therapy. One use of gene delivery in endodontics would be to deliver mineralizing genes into the pulp tissues to promote tissue mineralization. Gene therapy is a relatively a new field and evidence is lacking to demonstrate that this therapy has the potential to rescue the necrotic pulp.7

Conclusion Stem cells derived from all sources hold immense medical promises. Stem cell therapies have virtually unlimited medical and dental applications. While there are several barriers that need to be broken down before this novel therapy can be translated from lab to clinics, it is certain that the future is going to be exciting for all of us.

The need of the hour is high quality research coupled with collaboration between basic scientists and the clinicians. A team effort engaging the expertise of the molecular biologists, immunologists, biomaterial scientists, cell biologists, matrix biologists and practicing dental surgeons is crucial in attaining the desired goal.

References: 1.

K. Iohara, M. Nakashima, M. Ito, M. Ishikawa, A. Nakasima, A. Akamine. Dentin regeneration by dental pulp stem cell therapy with recombinant human bone morphogenetic protein 2. Journal of Dental Research 2004;83(8):590595.

2.

R. Langer, J. P. Vacanti. Tissue engineering. Science 1993;260(5110):920926.

3.

D. Tziafas, A. Alvanou, N. Panagiotakopoulos et al.

Induction of odontoblast-like cell differentiation in dog dental pulps after in vivo implantation of dentine matrix components. Archives of Oral Biology 1995;40(10):883893.

4.

N. T. Ishizaki, K. Matsumoto, Y. Kimura, X. Wang, A. Yamashita. Histopathological study of dental pulp tissue capped with enamel matrix derivative.

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Regenerative endodontics A review

Journal of Endodontics 2003;29(3):176179.

5.

6.

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R. B. Rutherford, K. Gu. Treatment of inflamed ferret dental pulps with recombinant bone morphogenetic protein-7. European Journal of Oral Sciences 2000;108(3):202206.

H. M. Blau, T. R. Brazelton, J. M. Weimann. The evolving concept of a stem cell: entity or function?

Cell 2001;105(7):829841.

7.

A.P. Chidgey, D. Layton, A. Trounson, R. L. Boyd.

Tolerance strategies for stem-cell-based therapies.

Nature 2008;453(7193):330337.

8.

L. M. Lin, P. M. Di Fiore, J. Lin, P. A. Rosenberg.

Histological study of periradicular tissue responses to uninfected and infected devitalized pulps in dogs. J Endod 2006;Jan32(1):34-38.

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Pictures

Fig.1 Shows how tissue engineering process is done.2

Fig.3: This is the ultrastructure of a human tooth with implanted pulp (shown in purple) created from stem cells and a scaffold in the laboratory3.

Fig.2: Regeneration of damaged part of tooth3

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Review article

Digital Photo Stimulable Phosphor (PSP) radiography-A review Mahesh M. S 1, Praveenkumar Ramdurg2, Manjunath N3 1. Senior Lecturer, Department of Oral Medicine and Radiology, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala.

2. Senior Lecturer, Department of Oral Medicine and Radiology, Vasantadada patil Dental College, Sangli, Maharashtra.

3. Reader, Department of Oral Medicine and Radiology,Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala.

Abstract For nearly 100 years, dental radiography has relied on film to perform the functions of image capture, image storage and image display. But, the need for chemical processing is the major drawback of film radiography. It also requires careful attention to maintain the correct developer temperature and chemistry. The need for manual storage and retrieval of radiographs are labor intensive and may result in lost radiographs. PhotoStimulable Phosphor radiography is now the cornerstone of film less radiography. It works on the principle of laser-induced emission of photo stimulated luminance.

Key words: Dental radiographs, Photostimulable Phosphor, Laser-induced emission.

Introduction Radiography in dentistry has a century old history.

Since then, it has become one of the most commonly and widely used adjunct to clinical examination.

The dental profession has recognized that radiographs are valuable tools for diagnosing questionable clinical findings because correct diagnosis forms basis for adequate dental treatment. Although many new diagnostic aids have been developed during the past decades, radiography continues to be the basis for the most diagnostic procedures and has become an essential procedure in practice of dentistry.

Radiographs show pathologic lesions or foreign bodies and developmental anomalies that cannot be identified in any other way and assist in the localization of these objects. Dental radiographs are used primarily to survey dental tissues for morphological/ pathological changes of diagnostic interest.

The film radiography has certain drawbacks1: 1. It is an inefficient photon detector, absorbing only a few percent of the total photons impinging upon it.

2. It provides a static image that cannot be significantly changed.

3. It requires processing, with the associated risk of information loss through suboptimal processing conditions.

4. Processing requires chemical solutions that are allergenic and environmentally polluting.

5. It is sensitive to variations in exposure.

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Even though the development of faster films has contributed to very significant reductions in dose, the large number of dental radiographs taken still means there is a need to lower individual exposures. Even with the latest high-speed films, the drawbacks associated with film based systems remain, and therefore the need for film less alternatives. 1 Photo Stimulable Phosphors (PSP) have been used in diagnostic radiology as an alternative to screen-film systems to capture radiographic images. After a radiographic exposure, image data are read out and stored in a computer. This decoupling of image capture from image storage and display is a major advance in medical imaging. In addition, eliminating chemical processing has the potential to reduce operating costs and improve the consistency of image quality.

Digital Photo Stimulable phosphor (PSP) radiography: History 2 The emission by a substance of stored energy as light is referred to as Luminescence. Observation of this phenomenon dates back to 1500 BC in china and was first described n 1603, with the preparation of the Bolognese stone (Barium sulfate), which glowed persistently after exposure to sunlight. In 1867, optical de excitation of atoms (stimulated luminescence) was noted, and in 1926, heat was described as a stimulus of luminescence. During World War II, such materials were

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Mahesh M.S, Praveenkumar Ramdurg, Manjunath N

used to produce night viewers (infrared scopes) and in 1947, it was proposed that if a phosphor were energized by exposure to X-rays, a latent image could be produced and stimulated at a later time with infrared light. In 1975, a patent was obtained for a general method of using scanning optics to release the energy from a storage phosphor and converting the information pattern into a digital form. The intent was to create a system that would be a more sensitive alternative to X-ray film (and avoid the high cost of silver).

Commercialization of these methods was first publicly presented in 1981 at the International congress of Radiology, and the first technical paper describing this methodology was published in 1983.

Fuji Photo Film Company (Tokyo, Japan) first introduced PhotoStimulable Phosphor in 1983. Since then, there have been numerous improvements in phosphors and imaging systems.

The technique is variously referred to as photostimulable phosphor, digital luminescence radiography, storage phosphor radiography, computed radiography and radioluminography.

Principles of photostimulable phosphor radiography 2, 3, 4, 5, 6, 7 In conventional film based panoramic radiography, radiographic films are used as image receptors where as in digital PSP based panoramic radiography, photostimulable phosphor plate sensors are used as image receptors.

In conventional film-based radiography, silver halide film performs all the functions of the imaging chain-acquisition of the image, image processing (by chemical development), transportation and storage and image display. With photostimulable phosphor, these functions are performed independently of each other.

Several attributes are required of a storage phosphor material. First, the compound must create and store the latent image without appreciable degradation until it is ready to be scanned. Second, it must be possible to stimulate efficiently the phosphor with light so that the stored energy in the latent image can be released. Third, the released energy must have a wavelength that can be readily detected in the presence of the stimulating light.

Europium-doped Barium Fluorohalide {(Ba, Eu)FX, where X is Br, Cl, or I}is the most commonly used compound. Europium is added as an impurity, acting as an activator to create luminescence centers (holes). The BaFX:Eu +2 is mixed with a polymer, which binds the storage phosphor crystals to a base. The storage phosphor is covered with protective coating, which helps prevent physical and atmospheric damage to the storage phosphor. This combination of storage phosphor, base and protective coating is referred to as storage phosphor plate. There is some variation among manufacturers with

regard to this basic structure, primarily whether the screen is rigidly mounted on a metal base or takes the form of a flexible sheet.

When the storage phosphor is exposed to X-rays, an electron of the Eu +2 ion is excited to the conduction band, creating an electron vacancy (hole) at the trivalent europium site (Eu +3). This electron is then trapped at a halogen vacancy (F-center) in the crystalline lattice of the storage phosphor. About half of the holes and trapped electrons recombine spontaneously and cause luminescence. The other half form metastable states, the local concentration of holes and trapped electrons being proportional to the local X-ray exposure. Because latent image formation is sufficient and because the phosphor absorbs more of the radition than nonscreen film, much lower exposures are required than for non-screen dental film; however, random thermal processes cause an exponential decay of the latent image through phosphorescence, with approximately 25% to 50% of the stored signal being lost within 1 hour after exposure. The remainder of the latent image persists for periods of days.

The excited BaFX complex has a rather wide absorption band centered at 600 nm. Red light from a helium-neon laser (wavelength 633 nm) or a semiconductor (diode) laser (680 nm) is used for stimulation. The red laser light releases the trapped electrons, which combine with the electron holes, reducing Eu +3 to Eu +2 and releasing light at 300 to 500 nm.

The red laser light (tens of milliwatts) is removed by optical filters and the green light (on the order of hundreds of picowatts) is detected by a photomultiplier tube (PMT).

The PMT is designed to convert small amounts of light into an amplified electric signal. At the PMT cathode, an electric field accelerates electrons released by incident photons. These electrons strike a series of electrodes (the dynode chain), each stage releasing a cascade of electrons that are further accelerated and multiplied. The number of electrons released and the signal strength are controlled by the potential (voltage) applied to the dynodes, with gains as high as 10,000 possible.

The resulting signal is converted to digital form by an analog-to-digital converter (ADC). Most ADCs have output resolutions of 8 to 16 bits, which restricts the output to limited range. (Each bit is a binary digit, so that the accessible signal range can be between 0 to 255 and 0 to 65,535). Three methods are commonly used to stay within the range of the ADC. In one approach, the plate is pre scanned to determine the required range, and this information is used to adjust the PMT voltage. In some cases, the PMT gain can be set to cover the range of exposures that would be normally encountered clinically.

In other applications, the signal is compressed by nonlinear (logarithmic or square-root) amplification before analogto-digital conversion.

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Digital Photo Stimulable Phosphor (PSP) radiography-A review

The ADC determines the maximum number of shades of gray (contrast resolution) of the image. It may also indirectly limit the exposure range by limiting the number of possible values at low exposures. The significance of each bit depends on the dimensional quantity being measured (eg; linear exposure signal or logarithm of exposure). Linear schemes are simpler and faster, but logarithmic schemes can cover broader ranges and correspond more closely to a film like look.

Most PSP systems output 10, 12, or 16 bits, but dental systems usually store images as 8-bit data.

Theoretically more the values, the smaller the differences that can be discerned between areas that receive different radiation doses.

A spatial resolution of approximately 12 line pairs per millimeter (lp/ mm) is achievable but is limited by scattering of laser light within the phosphor layer. In general, thin phosphor layers achieve better resolution and sharpness than thick layers but at a cost of increased exposure. Current dental PSP systems have a resolution of about 6 to 8 lp/mm.

A storage phosphor has a linear response to x-ray exposure, i.e. the amount of green light produced on stimulation with a laser is directly proportional to the Xray dose absorbed by the phosphor. Storage phosphors cover a wide range, with a linear response from 0 to about 500 mR. low exposures, down to about 0.005mR, can be detected. A well-defined, approximately logarithmic calibration over 4 orders of magnitude was demonstrated for a Fuji medical PSP system. In comparison, the dental film has an exposure range of about 100 to 1 (i.e an exposure that results in a black radiograph is about 100 times greater than an exposure that results in a barely discernible shade of gray). This narrow exposure range is necessary so that film produces high-contrast images that match the eye's response to variations in shades of gray.

To scan a PSP image, a focused laser beam is scanned across the plate. In the fast scan direction, a mechanical mirror deflects the laser beam or the phosphor screen is transported on a rotating drum. The orthogonal slow scan or sub scan motion is accomplished by linearly transporting the screen or laser.

The storage phosphor based images can be displayed on cathode ray tube (CRT) monitors or printed. Monitors and the associated workstations vary a great deal with regard to quality and available software for image processing. CRT monitors have number of limitations compared with light boxes, including lower luminance levels, a nonlinear transfer function and potential for fading, defocusing and geometric distortion. Another limitation of monitors is that they cannot display the spatial and gray-scale resolution inherent in the PSP image.

A brightly lit room also has a more deleterious effect on an image displayed on a CRT than it does on a

38

radiograph displayed on a light box. The clinical impact of these limitations is not clear and requires future research.

PSP Panoramic radiography

3, 4, 7, 8, 9

PSP based panoramic radiography was first described in 1985. Patient positioning and radiographic exposure is similar to the conventional film based panoramic radiographic technique but the image receptor is placed in the cassette without intensifying screens.

Schematic diagram of the Laser-scan panoramic imaging: The basic block diagram of the system is shown in figure. The primary feature of the system is that, in lieu of the film in a conventional apparatus, it has an imaging plate to temporarily store the x-ray energy pattern. In addition, an image reader converts the latent image on the imaging plate into digital time series signals, the image signals are converted by the image processor into digital information for computer processing and an image recorder subsequently records the processed signals onto a film.

Imaging plate (IP)

3,4,10, 11 ,12

The imaging plate is a polyester base, sprayed and coated with a crystalline halide composed of europiumactivated barium fluorohalide compounds. The plate is flexible, easy to handle and less than 1mm thick.

Imaging plates are available in various dimensions, for panoramic radiographs commonly used dimension is 300 X 150 Centimeters.

The principles for recording x-ray images on the IP and reading are shown in figure 6. The energy of the xrays reaching the IP is stored in the halide crystals.

Subsequent exposure of the IP to He-Ne laser beam (633 nm) releases the stored energy and results in the emission of blue light from the halide crystals, a phenomenon generally known as the Photostimulable luminescence. The correlation between the dose of x-ray radiation to the IP and the amount of the luminescence is linear over a wide range, making it possible to replace the x-ray information with the luminescence accurately.

A very small amount of the stored x-ray energy remains in the plate, even after the latent image has been converted to light. This residual energy can be eliminated by exposing the plate to sunlight; the plate can be used repeatedly.

Image reader/ scanner 3,4, 13, 14 The method by which the image reader converts the x-ray's latent image information into luminescence and then into electrical signals is illustrated in figure. The lumininescence of the IP is released by scanning the IP

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Mahesh M.S, Praveenkumar Ramdurg, Manjunath N

with a laser beam deflected by a vibrating mirror. The blue light emitted by the IP is conducted via photo-optic fibers to a photomultiplier for detection while the imaging plate moves in a direction perpendicular to the scanning direction. Thus, the intensity distribution of the stored x-ray energy on the IP is converted from optical signals into electrical signals, which are then fed into the image processor.

Image processor 3,4 The image processor uses a computer as the hardware for various algorithms capable of processing images useful for radiographic diagnosis. It is also capable of contrast enhancement, spatial frequency enhancement and various kinds of image information processing.

Image recorder 3,4 The digital signals as processed by the image processor are converted back into analog signals that modulate the intensity of another laser beam. The images obtained are recorded on a computer.

Advantages of Photostimulable phosphor radiography 4, 15, 16 1.

Storage phosphor plates can be reused indefinitely.

2.

PSP can be used with existing X-ray sources.

3.

Linear or logarithmic response to radiation is available.

4.

There is wide exposure range and fewer retakes.

Compared with dental Film, PSP is much more lenient with regard to using a specific exposure for a particular film type and patient.

5.

No chemical processing is required.

6.

Image processing of acquired images (post processing) is available. Because PSP images are digital, they can be processed to enhance features of interest and to suppress interfering anatomic structures and noise.

7.

2.

Images may initially appear different from filmbased images. It may take a while for the clinician to become comfortable with PSP images and with image processing in general.

3.

Phosphor plates must be packaged in sterile envelopes.

Conclusion The advantages of digital PSP based images over the conventional film radiography like the ability to manipulate the image after acquisition, a reduction in time between exposure and image interpretation and the ability to electronically archive patient clinical and radiographic data in one electronic file and various drawbacks of film radiography makes digital PSP based radiographs superior to conventional radiographs.

With the advent of film-less digital radiography, medical diagnostics has enhanced leaps and bounds.

Conventional film radiography though continues to be an integral part of the diagnostic radiology department. The diagnostic capabilities of both the techniques one time tested and the other recently introduced claiming several advantages over the other need to be assessed in the clinical setup.

References 1.

Eric whaites. Essentials of Dental Radiography and Radiology. 1st ed. Elsevier; 1992.

2.

Huda W, Lynn NR, Benn DK, Pettigrew JC. Comparison of a photostimulable phosphor system with film for dental radiology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997; 83: 725-31.

3.

Borg E and Grondahl. On the dynamic range of different X-ray photon detectors in intra-oral radiography. A comparison of image quality in film, charge-coupled device and storage phosphor systems. Dento Maxillofac Radiol 1996; 25(2): 82-88.

Images can be transferred to other sites. Because the PSP images are in digital form, they can be transferred.

4.

Hildebolt C F, Couture R A and Whiting B R. Dental Potostimulable Phosphor Radiography. Dental Clinics of North America 2000; 44(2): 140-148.

8.

Images can be easily and inexpensively stored and retrieved.

5.

Frommer HH. Radiology for Dental Auxiliaries. 7th ed. St. Louis: C.V Mosby ; 2001.

9.

Computer-aided diagnosis.

6.

White SC, Pharoah MJ. Oral Radiology, Principles and interpretation. 6th ed. St. Louis: Mosby; 2005.

7.

Langland OE and Langlais RP. Principles of Dental imaging. 1st ed. Edward Brothers. Baltimore; 1997.

8.

Scarfe WC, Eraso FE, Farman AG. Characteristics of the Orthopantomograph OP100. Dent Maxillofac Radiol 1998; 27:51-57.

Disadvantages/ Limitations of Photostimulable phosphor radiography 4, 15, 16 1.

Although PSP image display is much more flexible than film image display, the display method is still not being optimal. Additional research is needed to determine the requirements for image display.

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Digital Photo Stimulable Phosphor (PSP) radiography-A review

9.

Mason-Hing LR. Fundamentals of Dental Radiography.

3rd ed. Philadelphia: Lea and Febiger ; 1991.

10. Lyre WR, Johnson ON. Essentials of dental radiography for dental assistants and hygienists. 4th ed. Prentice-Hall; 2000.

11. Kashima I, Kanno M, Higashi T, Takano M, Yokosuka and Kanagawa. Computed panoramic tomography with scanning laser-stimulated luminescence. Oral Surg Oral Med Oral Pathol 1985; 60: 448-53.

12. Borg E and Grondahl. Endodontic measurements in digital radiographs acquired by a photostimulable storage phosphor system. Endod Dent Traumatol 1996: 12: 20-24.

13. Borg E and Grondahl HG. On the dynamic range of different X-ray photon detectors in intra-oral

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radiography. A comparison of image quality in film, charge-coupled device and storage phosphor systems. Dento Maxillofac Radiol 1996; 25: 82-88.

14. Hildebolt C F, Fletcher G, Crothers N Y, Conover G L and Vannier M W. A comparison of the response of storage phosphor and film radiography to small variations in X-ray exposure. Dento Maxillofac Radiol 1997; 26: 147-151.

15. Borg E, Attaelmanan A and Grondahl H G. Subjective image quality of solid-state and photostimulable phosphor systems for digital intraoral radiography. Dento Maxillofac Radiol 2000; 29: 70-75.

16. Attaelmanan A, Borg E and Grondahl HG. Digitization and display of intra-oral films. Dento Maxillofac Radiol 2000; 29: 97-102.

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Pictures

Fig. 1 Schematic diagram of the Laser-scan panoramic imaging:

Fig. 2 Principle of the imaging plate

Fig. 3 Construction of the image reader JOURNAL OF DENTOFACIAL SCIENCES AND RESEARCH 2011; 1(1):36-41.

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Review article

Oral clear cell tumors - A review Adarsh H, Suhas R. Nayak 1.Senior Lecturer, 2. Senior Lecturer, Department of Oral and Maxillofacial pathology, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala.

Correspondence: Adarsh H, Senior Lecturer, Department of Oral and Maxillofacial Pathology, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala. e-mail: adarsh81h@gmail.com

Abstract Clear cells most frequently represent a minor element in an otherwise typical tumor. 15 to 20% of head and neck tumors comprise of clear cells which are derived from wide variety of tissues. When these cells predominate in a given tumor, a definitive diagnosis may be problematic since many of these tumors which constitute clear cells as a major component share similar histological features. This article reviews clear cell tumors that arise in the head and neck region, mainly the oral cavity and discusses on the histopathological, ultrastructural as well as immunohistochemical features that aid in the differentiation of these tumors.

Key words: Clear cells, Ultrastructure, Histopathology, Immunohistochemistry (IHC).

“Vision is not what the eyes see, but also what they don't see”. There is always more than what meets the eye. This kind of insight usually comes with experience. But, there are certain situations which may prove to be a challenge, even to the experienced eye.

Such a situation can be created by just a cell, namely the 'Clear cell', which may put even the experienced pathologist in a dilemma. The presence of minimal amount of clear cells with characteristic histological features would not hinder the routine diagnosis but on the other hand neoplasms that are composed entirely or predominantly of cells with clear cytoplasm need to be diagnosed with the help of other diagnostic adjuvants such as special stains, ultra-structurally and by immunohistochemical procedures.

The tumors which comprise clear cells as a component can be classified according to the probable cell of origin as follows:

·

Clear cell mucoepidermoid carcinoma

·

Epithelial-myoepithelial carcinoma

C) Tumors of epithelial origin ·

Clear cell variant of squamous cell carcinoma

·

Clear cell variant of basal cell carcinoma

D) Tumors of skin appedeges ·

Trichelemomma

·

Acanthoma

·

Sebaceous gland tumor and carcinoma

·

Tumors of the sweat gland

E) Melanocytic tumors ·

Balloon cell nevous

·

Clear cell variant of melanoma

F) Metastatis from renal cell carcinoma A) Odontogenic tumors ·

Clear cell calcifying epithelial odontogenic tumour (CEOT)

·

Clear cell odontogenic carcinoma

B) Salivary gland tumors

42

·

Clear cell oncocytoma

·

Clear cell acinic cell carcinoma

·

Hyalinizing clear cell carcinoma

G) Miscellaneous tumors containing clear cells ·

Clear cell chondrosarcoma

·

Tumors

of

adipose

tissue

Clear cell odontogenic carcinoma (CCOC) CCOC histologically exhibit 3 patterns most commonly a biphasic tumor characterized by oval and linear nests of large clear cells intermixed with smaller islands of smaller polygonal cells with eosinophilic cytoplasm.1-3 Second pattern is characterized by islands

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that show only the clear cell phenotype (figure 1). The third and least common variant is comprised of clear cell nests with a tendency for ameloblastoid palisading at the periphery (figure 2). Central stellate reticulum like cells showed cystic degeneration, squamous and spindle cell differentiation and occasional keratinization.4,5 Clear cells contain glycogen and stains positively with PAS. Mucicarmine and alcian stains are negative in all cases except one. Tumor cells show cytokeratin and epithelial membrane antigen positivity.2-5 Actin, vimentin, muscle specific antigen (MSA) and S-100 are negative.3

Clear cell calcifying epithelial odontogenic tumour (CCCEOT) CCCEOT shows sheets, strands or clusters of classic polyhedral epithelial cells with abundant eosinophilic, granular or clear cytoplasm may alternate with zones of large cells with clear foamy cytoplasm and distinct cell borders. Calcified foci and liesegang type calcifications are found. Amorphous eosinophilic areas of amyloid are noted in the connective tissue.1,6 Tumor cells are positive for diastase digested and non digested PAS reaction. Amyloid stains positively with Congo Red stain and Dylan. Amyloid under polarized light appears green birefringence.

Amyloid appears fluorescent yellow with Thioflavin T and orange with Congo red. Tumor cells are positive for CKs AE1/AE3 and 14 but negative for all other CKs. Amyloid is positive for fibronectin and type IV collagen. Langerhan's cells are positive for S-100.1,3

Salivary gland tumors Clear cell appearance is the light microscopic manifestation of 3 basic factors due to large amount of cytoplasmic glycogen and a normal complement of subcellular organelles (glycogen rich), little or no demonstrable glycogen and paucity of organelles (nonglycogen containing) and due to the post removal or fixation artifact (artifact).

Many salivary gland tumors contains mucus secreting as well as clear cell. The mucous cell component is basophilic and will stain positively with mucicarmine or alcian blue. The true clear cell tumors fail to stain positively for mucosubstance. These clear cell salivary tumors are differentiated from one another on variety of histopathological features that is discussed below.7

Clear cell oncocytoma Clear cell oncocytoma is composed of well circumscribed masses of large polyhedral cells arranged in an organoid fashion with thin vascular fibrous septa.

Most of these cells are completely clear whereas others show variable amount of eosinophilic granular cytoplasm at

the periphery. Transition from typical eosinophilic oncocytes to clear cell forms is evident in some areas. Staining with PAS reveal inconsistent glycogen content, whereas PTAH stains are distinctly positive.8 A recent electron microscopic study of clear cell oncocytes showed considerable collections of glycogen occupying the central region of tumor cells. The most difficult differential diagnosis of this lesion is with acinic clear cell carcinoma, which usually displays amylase immunoreactivity. The clear cell oncocytoma appears to be expansive rather than infiltrative like carcinomas.

Clear cell oncocytoma is differentiated from epithelial myoepithelial carcinoma by the lack of characteristic bicellular pattern.8

Clear cell acinic cell carcinoma Acinic cell carcinomas are generally infiltrative but may indeed be relatively circumscribed. Several cell types may be recognized including acinar, intercalated duct like, vacuolated, clear and non-specific glandular elements. Tumor cells rarely contain zymogen type granules. They usually show large cytoplasmic volume with faint basophilic or eosinophilic granules.9 These acinar cells stain positively with PAS with and without diastase digestion but not with alcian blue. Admixed with the acinar cells are clear cells usually arranged in sheets but may be seen as single cells or small clusters lining the microcystic spaces. These cells rarely constitute more than 50% of the lesion and they do not contain glycogen.8,10 IHC show varying staining reactions depending on the cell type and the differentiation of the tumor. The tumor is positive for amylase, cytokeratin, S100 protein and vimentin.10

Hyalinizing clear cell carcinoma (HCCC) Hyalinizing clear cell carcinoma (HCCC) is a recently described neoplasm by Milchgrub et al.11 Microscopically, HCCC is characterized by trabeculae and islands of clear cells with hyalinized stroma.

However, smaller cells with eosinophilic cytoplasm as well as areas of squamous metaplasia have also been reported.12 As clear cells are known to occur in many salivary gland tumors, demonstration of CK positivity and S-100 and SMA negativity would be mandatory to diagnose HCCC.12 Rarely the tumor cells are positive for carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA). The clear cells are usually due to accumulation of glycogen and not mucin.11 HCCC can be differentiated from following lesions by their peculiar feature which are not seen with HCCC Clear cell mucoepidermoid carcinoma (Alcian blue positive), Clear cell acinic cell carcinoma (Amylase positive), Clear cell malignant melanoma (S-100 and HMB-45 positive).11

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Oral clear cell tumors – A review

Clear cell mucoepidermoid carcinoma Mucoepidermoid carcinoma (MEC) is most common malignancy of the parotid gland but a significant number of cases (40%) arise in the minor salivary glands.

These tumors are biphasic with a squamous and a mucous cell component. In addition cells with features of both the types are commonly seen and are termed as intermediate cells. Epidermoid cells are most easily detected by its appearance. Mucous cells may contain intracytoplasmic granules which stain positively with PAS with or without diastase digestion, as well as alcian blue. The intermediate cells possess the morphologic features of both cells and are round to oval with slightly eosinophilic cytoplasm and centrally placed round nucleus.

Clear cells are variably present in the MEC. These clear cells show solid pattern of growth consisting of large polyhedral cells with uniformly clear cytoplasm or finely dispensed granules. These structures may contain PAS positive, diastase sensitive droplets of glycogen together with acid mucopolysaccharide. 1 0 The distinguishing feature not seen in other clear cell tumors, is the formation of squamoid condensation primarily found around the periphery of the tumor islands and adjacent to vascular septa. Accurate differential diagnosis with other clear cell salivary gland tumors depends on an exhaustive search for intermediate cells and Alcian blue PAS positive mucin producing cells.10

Epithelial-myoepithelial carcinoma (EMC) EMC is a rare tumor representing less than 1% of all salivary gland tumors and takes origin from intercalated duct.13 Characteristically, the clear cells surround tubular lumen composed of simple cuboidal ductal cells with eosinophilic cytoplasm. In many of these tumors, the lobules are comprised of organoid or acinar like configuration in which the tubular ducts are enveloped by an outer clear cell rosette. This pattern resembles an intercalated salivary duct in which surrounding myoepithelial cells have transformed into clear cells giving a bicellular arrangement. The clear cells are either oval or have a spindle streaming appearance with a centrally placed nuclei which is oval or vesicular.10 Electron microscopic and IHC studies have confirmed that the clear cells are typical of myoepithelial phenotype. They show S-100 protein, vimentin, myosin and K-1 actin positivity. IHC for the inner cell layer displays cytokeratin and EMA reactivity.10

Tumors of adipose tissue, skin appendages, epithelial origin and melanocytes The occurrence of these tumors within the oral cavity is very rare and hence these tumors are not thoroughly reviewed. These tumors can be easily

44

diagnosed microscopically since clear cells are only a minor component of these tumors. Histologic appearance of tumors of adipose tissue is very characteristic and can easily be differentiated from other clear cell tumors, even in H & E staining.

Focal sebaceous differentiation may be found in several salivary gland tumors. These include sebaceous adenoma and lymphadenoma and sebaceous carcinoma with or without lymphoid stroma.

All are rare and usually occur in parotid gland. The tumor cells are large with foamy cytoplasm filled with PAS and alcian blue negativity vesicles but positivity with oil-red and Sudan IV.2 Squamous and basal cell carcinomas have been reported to manifest clear cell variants and 90% of such neoplasms are located on the skin of head and neck. The tumor cells are arranged in islands and sheets with unmistakable origin from the surface. Although individual islands may be composed exclusively of clear cells, neighboring cells will exhibit the typical features of either basal or squamous cell carcinoma.10

Miscellaneous tumors Metastasis of renal cell carcinoma constitute 15% of head and neck. Thyroid is the most common site of metastasis from renal cell carcinoma. Metastases to trachea, laryngopharynx, gingival and nasal cavity have been reported.14 These tumors have a similar appearance to that of salivary gland tumors. Cytoplasm of renal tumor and other parotid clear cell tumors contain PAS positive granules that are diastase-soluble, mucicarmine and alcian blue negative. Renal cell carcinoma may sometimes be distinguished by positive cytoplasmic staining with Sudan black or oil red but frozen sections are needed. Primary parotid neoplasms usually are CEA and keratin positive and are vimentin negative. The clear cell and chromophillic types (granular) of renal clear cell carcinomas are CEA-negative and are keratin and vimentin positive.10,15 Chondrosarcoma is a malignant tumor characterized by the formation of cartilage, but not bone, by the tumor cells. Chondrosarcomas comprise about 10% of all primary tumors of skeleton. Clear cell chondrosarcoma is considered to be a low grade lesion and can be differentiated from other tumors by its S-100 positivity.16

Summary The clear cell tumors are derived from diverse group of cell types like odontogenic epithelium, salivary glands, keratinocytes, skin appendages, melanocytes, renal epithelium and even mesenchymally derived cells like adipose tissue. Since most of these tumors share similar histopathological features ie. the clear cells in the

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Adarsh H, Suhas R. Nayak

tumor mass, the definitive diagnosis of clear cell tumors of head and neck region is always problematic for histopathologists. So as to differentiate and thoroughly identify the probable cell of origin of these tumors they have been classified accordingly and the diagnosis is established by a combination of various diagnostic adjuvants.

References

8.

Ellis GL. "Clear cell" oncocytomas of salivary gland. Hum Pathol. 1988;19:862-867.

9.

Echevarria RA. Ultrastructure of acinic cell carcinoma and clear cell carcinoma of parotid gland.

Cancer 1967;20:563-571.

10. Eversole LR. On the differential diagnosis of clear cell tumors of the head and neck region. Eur Jr Cancer B Oral Oncol 1993;29:173-179.

1.

Ariyoshi I, Shimahara M, Miyuchi M, Nikai H. Clear cell odontogenic carcinoma with ghost cells & inductive dentin formation- report of a case in the mandible. J Oral Pathol Med 2002;31:181-183.

11. Milchgrub S, Vuitch F, Saboorian MH, Hameed A, Wu H. Hyalinizing clear cell carcinoma of salivary gland in fine needle aspiration. Diag cytopathol 2000;23:333-337.

2.

Bang G, Koppang HS, Hansen LS et al. Clear cell odontogenic carcinoma; report of three cases with pulmonary & lymph node metastases. J Oral Pathol Med 1989;18:113-118.

12. Behro M, Huvos AG. Central hyalinizing clear cell carcinoma of the mandible and maxilla. A clinicopathologic study of two cases and analysis of literature. Hum Pathol 1999;30:101-105.

3.

Benton DC, Eisenberg E. Clear cell odontogenic carcinoma report of a case. J Oral Maxillofac Surg 2001;59:83-88.

4.

Aguair MCF, Gomez RS, Sliva EC, Araujo VC. Clear cell ameloblastoma (clear cell odontogenic carcinoma): Case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;81:79-83.

13. Corio RL. Epithelial-myoepithelial-carcinoma. In: Ellis GL, Auclair PL, Gnepp DR, eds. Surgical Pathology of the Salivary Glands. Philadelphia, Pa: WB Saunders Co; 1991:412-421.

14. Boggess MA, Hester TO, Archer SM. Renal clear cell carcinoma appearing as a left neck mass. Ear Nose Throat J 1996;75:620-622.

5.

Maiorano E, Altini M, Viale G, Piattelli A, Favia G. Clear cell odontogenic carcinoma . Report of 2 cases and review of literature. Am J Clin Pathol 2001;116:107-114.

15. Melenik SJ. metastatic renal cell carcinoma presenting as a parotid tumor. A case report with immunohistochemical finding and review of literature. Hum Pathol 1999;20:195-197.

6.

Schmidt-Westhausen A, Philipsen HP, Reichart PA. Clear cell calcifying epithelial odontogenic tumor.

A case report. Int J Oral Maxillofac Surg 1992;21:47-49.

16. Neville BW, Damm DD, Allen CM, Bouquot JE. Oral and maxillofacial pathology, 2nd ed.

Philadelphia: WB Saunders; 2002:578-580.

7.

Fujita H, Iida M, Imura J, Shaingowa Y, Oetehara F, Kawamata H, Imai Y and Fujimari T. Clear cell adenocarcinoma of tongue. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:579-582.

17. Reichart PA, Philipsen HP. Odontogenic tumors and allied lesions. London: Quintessence; 2004:243.

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Oral clear cell tumors – A review

Pictures

Figure 1: CCOC showing polygonal clear cells with lack of palisading.17

Figure 4: Clear cell variant of oncocytoma.8

Figure 2: CCOC showing palisading of ameloblast like cells.17

Figure 6: Clear cell acinic cell carcinoma showing clear cells. 9

Figure 3: CCCEOT showing clear cells and calcification.

Inset showing cells with hyperchromatic centrally placed nucleus.6

Figure 5: Mucoepidermoid carcinoma showing clear cytoplasm of mucus and epidermoid cells.10

46

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Review article

Photodynamic Therapy in Periodontics 1

Rajeev K, Karthika R

2

1, 2. Senior Lecturer, Department of Periodontics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram.

Correspondence: Rajeev K, Senior Lecturer, Department of Periodontics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram District, Kerala. e-mail: rajeev_mds@yahoo.co.in

Abstract The oral cavity is colonized by a large number and highly diversified communities of micro-organisms.

Bacterial biofilm present on tooth or root surface is a major cause of gingivitis and periodontitis. Chemical antimicrobial agents are widely used in prophylactic and therapeutic regimens for dental plaque related diseases, which are among the most common human infections. As these agents are difficult to maintain at therapeutic concentrations in the oral cavity and can be rendered ineffective by resistance development in target organisms, there is a need for an alternative antimicrobial approach. A novel approach, photodynamic therapy (PDT), could be a solution to these problems. Lethal photosensitization of many bacteria, both Gram positive and Gram negative was found in many studies. The advantage of this new approach includes rapid bacterial elimination, minimal chance of resistance development and safety of adjacent host tissue and normal microflora. Thus, the available knowledge of photodynamic therapy should encourage a more clinically oriented application of this technique.

Keywords: Antimicrobial chemotherapy, periodontal disease / Microbiology, Peri-implantitis, Phototherapy, Scaling and root planing.

Introduction Periodontal disease is initiated by pathogenic plaque biofilm and characterized by bacteria-induced inflammatory destruction of tooth-supporting structures and alveolar bone.

Mechanical scaling and root debridement have shown to be an effective treatment approach for periodontal disease.1,2 However, the limitations of scaling and root debridement have also been shown in management of initially deep periodontal pockets and furcation involved lesions.3, 4 In recent years, various innovative adjunctive treatments have therefore been developed to improve the clinical effectiveness of scaling and root debridement.

Photodynamic therapy (PDT) is a medical treatment that utilizes light to activate a photosensitizing agent (photosensitizer) in the presence of oxygen. The exposure of the photosensitizer to light results in the formation of oxygen species, such as singlet oxygen and free radicals, causing localized photodamage and cell death. Clinically, this reaction is cytotoxic and vasculotoxic. Depending on the type of agent, photosensitizers may be injected intravenously, ingested orally, or applied topically. The relative simplicity of the mechanism of activation of photosensitizers has stimulated considerable interest in PDT. Photodynamic antimicrobial chemotherapy (PACT)

represents an alternative antibacterial, antifungal, and antiviral treatment for drug-resistant organisms.5 It is unlikely that bacteria would develop resistance to the cytotoxic action of singlet oxygen or free radicals.

Bacteria that grow in biofilms, implicated in diseases like cystic fibrosis (Pseudomonas aeruginosa) or periodontitis (Porphyromonas gingivalis), are also susceptible to PDT.6,7 Applications of PDT in dentistry especially in the field of periodontology is growing rapidly. The aim of this review is to outline the clinical results of PDT for the treatment of periodontal diseases.

Photodynamic reaction PDT involves three components: light, a photosensitizer, and oxygen. A photosensitizer or its metabolic precursor is administered to the patient. Upon irradiation with light of a specific wavelength, the photosensitizer undergoes a transition from a low-energy ground state to an excited singlet state. Subsequently, the photosensitizer may decay back to its ground state, with emission of fluorescence, or may undergo a transition to a higher-energy triplet state. The triplet state can react with endogenous oxygen to produce singlet oxygen and other radical species, causing a rapid and selective destruction of the target tissue (Fig. 1).

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Photodynamic Therapy in Periodontics

There are two mechanisms by which the triplet-state photosensitizer can react with biomolecules: Type I involves electron/hydrogen transfer directly from the photosensitizer, producing ions, or electron/hydrogen removal from a substrate molecule to form free radicals. These radicals react rapidly with oxygen, resulting in the production of highly reactive oxygen species (superoxide, hydroxyl radicals, hydrogen peroxide).

Type II reactions produce the electronically excited and highly reactive state of oxygen known as singlet oxygen. In PDT, it is difficult to distinguish between the two reaction mechanisms. A contribution from both Types I and II processes indicates that the mechanism of damage is dependent on both oxygen tension and photosensitizer concentration.

PDT produces cytotoxic effects through photodamage to subcellular organelles and molecules.

Mitochondria, lysosomes, cell membranes, and nuclei of tumor cells are considered potential targets, along with the tumor vasculature. During light exposure, sensitizers that localize in mitochondria may induce apoptosis, while sensitizers localized in lysosomes and cell membranes may cause necrosis.8

Light source PDT requires a source of light that activates the photosensitizer by exposure to low-power visible light at a specific wavelength. Human tissue transmits red light efficiently, and the longer activation wavelength of the photosensitizer results in deeper light penetration.

Consequently, most photosensitizers are activated by red light between 630 and 700 nm, corresponding to a light penetration depth from 0.5 cm (at 630 nm) to 1.5 cm (at ~ 700 nm).9 We have 3 light systems for the therapy: 1. Diode laser systems: they are easy to handle, portable and cost-effective.

2. Non-coherent light sources: preferred for treatment of larger areas and include tungsten filament, quartz halogen, xenon arc, metal halide and phosphorcoated sodium lamps.

3. Non-laser light sources include lightemitting diodes (LED). They are economical, light weight and highly flexible.10

Photosensitizer Requirements of an optimal photosensitizer include following characteristics:

48

1. Highly selective tumor accumulation : targetibility.

2. Low toxicity and fast elimination from the skin and epithelium.

3. High quantum yield of singlet oxygen production in vivo.

4. Cost effectiveness and commercial availability.

5. High solubility in water, injection solutions, and blood substitutes .

6. Storage 11 The various agents can be grouped under 3 generations.12 First genetation include photofrin (most extensively used) and hematoporphyrin derivatives (HPD). Second generation include 5-aminolevulinic acid (ALA), benzoporphyrin derivatives (BPD), temoporfin (mTHPC) and talaporphin sodium (LS11). Foscan (mTHPC) is the most potent amongst them. ALA, is an intrinsic photosensitizer that is converted in situ to a photosensitizer, protoporphyrin IX. Topical ALA and its esters have been used to treat pre-cancer conditions, and basal and squamous cell carcinoma of the skin.13 Thirdgeneration photosensitizers include currently available drugs that are modified by targeting with monoclonal antibodies or with non-antibody-based protein carriers and protein/ receptor systems, and conjugation with a radioactive tag. Currently only 3 agents have been approved by FDA - Porfimer sodium, ALA and Vertoporfin. Foscan is in used only in European countries.

Advantages of PDT9 · Therapy has only localized effects as the photosenstizer is selectively absorbed at a greater rate by target tissues. · This can be performed in outpatient or day-case settings. · This is more economical than radiation and surgical therapy for cancer patients. · It has faster post-op healing · There are no long term side effects. · It is less invasive and can be repeated many times at the same site if needed, unlike radiation.

11

Limitations

· Light is needed to activate photosensitizer. · Cannot penetrate more than 1cm of tissue depth using standard laser and low powered LED technology and hence is less effective in treatment of large tumors and metastasis.

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Rajeev K, Karthika R

路 It may leave many people very sensitive to light post therapy 路 Cannot be used in people allergic to porphyrins.

Role in Periodontology Biofilm in oral cavity causes two of the most common diseases, dental caries and periodontal diseases.

An effective approach of periodontal therapy is to change the local environment to suppress the growth of periodontal pathogens. Micro-organisms in gelatinous matrix (glycocalyx) are less accessible to antibiotics.

Using antimicrobial agents to treat periodontitis without disruption of the biofilm ultimately results in treatment failures. It is difficult to maintain therapeutic concentrations at the target sites and target organisms can develop resistance to drugs. This resistance is minimized by using PDT. Polysaccharides present in extracellular matrix of oral biofilm are highly sensitive to singlet oxygen and susceptible to photodamage. Breaking the biofilm may inhibit plasmid exchange involved in transfer of antibiotic resistance and disrupt colonization.7 PDT is even effective against antibiotic resistant bacteria.

Antioxidant enzymes produced by bacteria may protect against some oxygen radicals, but not against singlet oxygen.5.

Photodynamic antimicrobial chemotherapy could be an ideal complement to conventional scaling and root planing. It employs a quick and simple protocol that allows the clinician to kill bacteria, inactivate virulence factors left behind after scaling and root planing. It is used during initial and maintenance therapy for the treatment of periodontitis. The activity of PDT against periodontopathic bacteria has been reported in vitro and in vivo for a range of photosensitizers.

During inflammation there is venous stagnation and reduced oxygen consumption by tissues. This decrease in oxygen level and change in pH may enhance the growth of anaerobic species. In such cases, PDT may improve tissue blood flow in the microcirculatory system and reduce venous congestion in gingival tissues. 14 Furthermore, PDT may increase oxygenation of gingival tissues by 2147 per cent. This in turn decreases the time and speed of oxygen delivery and utilization, thus normalizing oxygen metabolism in periodontal tissues.14 The susceptibility to destruction of bacteria by PDT is different between Gram positive and Gram negative species. Gram positive bacteria are more susceptible to photoinactivation than Gram negative bacteria. The structural variations in their cytoplasmic membrane are responsible for the enhanced susceptibility of Gram

positive bacteria to binding to photosensitizers. In Gram positive bacteria, the relatively porous outer cytoplasmic membrane, peptidoglycans, and lipoteichoic acid outside the cytoplasmic layer allow the neutral or anionic photosensitizer to bind efficiently to diffuse into sensitive sites. In Gram negative bacteria, the structure of the outer membrane is more complex, forming a physical and functional barrier between the cell and its environment, thereby making it difficult for the photosensitizer to gain access into internal target sites.15 However, this diffusion may be enhanced by: (1) linking the sensitizer to a polycationic molecule (poly-L-lysine-chlorine, polymyxin B nonapeptide).

These weaken the intermolecular interactions of the lipopolysaccharide constituents, disorganize the structure, and render it permeable to drugs by enabling them to cross the outer membrane;16 (2) use of membrane active agents (treatment with trisEDTA), which release lipopolysaccharide or the induction of competence with sensitizedpathogen;17 and (3) conjugating the sensitizer to monoclonal antibodies that bind to cell-surfacespecific antigens.18 The selective uptake of photosensitizers by bacteria can be enhanced by conjugation with various peptides.

For example, Poly-L-lysine (pL)chlorine e6 conjugates kill P. gingivalis without affecting the viability of epithelial cells. The polycationic lysine polypeptide is responsible for the initial binding of the photosensitizer to bacteria due its structural similarity to antimicrobial peptides causing cell lysis.20 Linking the toludine blue O to a monoclonal antibody has been shown to inactivate the lipopolysaccharide of P. gingivalis.18 Hence, conjugated photosensitizers are beneficial in targeting bacteria or particular virulence factors without damaging epithelial cells.

The roles of virulence factors in pathogenesis of periodontal diseases are well documented.

Lipopolysaccharide possess a wide spectrum of immunological and endotoxin activities. It can cause activation of macrophages, production of interleukin-1, release of prostaglandin E2, the local Schwartzman reaction and is a potent stimulator of bone resorption in inflammatory periodontal diseases. Endotoxin on root surface inhibits fibre reattachment on cementum. PDT has another advantage in inactivating virulence factors secreted by micro-organisms. Following exposure of P. gingivalis to low-energy He-Ne laser (632 nm) and TBO (25 um/ ml), the activity of lipopolysaccharide and IL-1 secretion from human peripheral mononuclear cells exposed to such treatment were significantly reduced.20

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Photodynamic Therapy in Periodontics

In addition, there was a substantial, light dose dependent decrease in the proteolytic activity (94 per cent) of P. gingivalis.21 Such effects may be of benefit in the treatment of infections due to these organisms.

There are two basic mechanisms that have been proposed to account for the lethal damage caused to bacteria by PDT: (1) DNA damage and (2) damage to the cytoplasmic membrane, allowing leakage of cellular contents or inactivation of membrane transport systems and enzymes.15 Breaks in both single- and doublestranded DNA, and the disappearance of the plasmid supercoiled fraction have been detected in both Gram positive and Gram negative species after PDT with a wide range of photosensitizer structural types. Although DNA damage occurs, it may not be the prime cause of bacterial cell death. The alteration of cytoplasmic membrane proteins, disturbance of cell-wall synthesis and the appearance of a multi-lamellar structure near the septum of dividing cells, along with loss of potassium ions from the cells may be other possible ways of bacterial death.22,23 It has been hypothesized that photosensitizers that operate chiefly via Type I mechanisms penetrate the outer membrane of Gram negative bacteria, while the Type II photosensitizers penetrate the outer membrane of Gram positive bacteria more efficiently.15 The bactericidal activity of PDT depends on various factors. The surface charge of the photosensitizer determines its binding with the cell membrane. The electrostatic interaction between the positively charged surface of photosensitizer and the negatively charged membrane of the bacteria can affect bacterial killing. In an in vitro experiment, the polycationic conjugation of ce6 molecules to pL (5 lM concentration) on P. gingivalis produced 99% killing and on A. viscosus >99.99% after one minute of incubation after exposure to red light for 10 minutes in a concentration-dependent manner. The polycationic charged polypeptide, lysine, is probably responsible for the initial binding to bacteria.19 But even non-cationic compounds photosensitizers, such as porphycenepolylysine conjugates, are used in the inactivation of both Gram positive and Gram negative bacteria provided they are bound to a polylysine moiety.24,25 The environmental conditions surrounding bacteria may influence the efficient binding of photosensitizers. In vitro studies have shown that blood agar culture media, hemin content and the pH of the medium used may inhibit the binding of photosensitizer with pathogens. Blood contained in the culture media adsorbs the part of laser light, hemin competes with the photosensitizer binding sites and bacterial metabolic by-products alters the pH of

50

the medium. All of these alter the binding of the photosensitizers to the target sites, resulting in less binding and reduced photoinactivation.26,27,28 However, the black-pigmented species, such as P. gingivalis, Prevotella intermedia and Prevotella nigrescens, are more susceptible to elimination by lethal photosensitization.

Intracellularly, they accumulate various amounts of different porphyrin molecules (P. intermedia 267 ng / mg, P. nigrescens 47 ng / mg, P. melaninogenica 41 ng /mg and P. gingivalis 2.2 ng / mg), together with varying amounts of iron-free protoporphyrin IX. These photosensitive porphyrins absorb visible light at different wavelength and different energy level and enhance the killing effect.29 Various in vitro studies have shown that periodontal micro-organisms are killed more than 45 times at micromolar concentration after incubation times as short as 510 minutes and irradiation under mild experimental conditions, such as fluence rates around 50 mW/cm2 and irradiation times shorter than 15 minutes.30 Whether PDT can be clinically implemented as a successful antiinfectious procedure in periodontal diseases is not clear because of a lack of controlled clinical studies. However, the clinical applicability of PDT in treatment of periodontitis has been tested in the non-surgical management of aggressive periodontitis. PDT and nonsurgical periodontal treatment show similar clinical outcomes at three months evaluation35 without difference in crevicular Tumor necrosis factor-ι (TNF-ι) and Receptor activator of nuclear factor kappa-β ligand (RANKL) concentrations at 30 days interval.32 In another study, only bleeding on probing was significantly decreased when compared to other parameters at six months interval.33 However, it has also been reported that PDT adjunctive to non-surgical periodontal treatment enhances the clinical outcomes.34 In this three month splitmouth study, gingival bleeding, probing depth, gingival recession, attachment level and gingival crevicular fluid flow rates were significantly decreased showing higher impact of PDT on the treated sites.34 Moreover, a reduction in gingival recession compared to non-surgical periodontal therapy in aggressive periodontitis patients has been reported.35 From the above, it is clear that further clinical trials are required for definitive assessment of PDT in the field of periodontal therapy.

Conclusion This new strategy of using PDT is less traumatic and quicker in the treatment of periodontal diseases but it is still in the experimental stage of development and testing.

Development of new photosensitizers, more efficient light delivery systems and further clinical studies are required to

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Rajeev K, Karthika R

establish the optimum treatment parameters for PDT. Photodynamic therapy in vitro studies have shown greater (>95%) reduction in micro-organisms. Clinical trials are also encouraging. In addition to reducing clinical parameters in periimplantitis cases, there is some evidence that PDT will also inactivate virulence factors of periodontal pathogens, enhancing post-treatment outcomes. PDT offers numerous advantages, particularly in avoiding emergence of antibiotic resistance species, requiring less technical skills and reducing operating time in comparison to manual scaling and root planing. As a new approach, PDT could be useful as an adjunct or conventional therapy during the maintenance period.

References 1.

2.

3.

4.

5.

6.

7.

8.

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Morrison EC, Ramfjord SP, Hill RW. Short-term effects of initial, nonsurgical periodontal treatment (hygienic phase). J Clin Periodontol 1980;7:199211.

Van der Weijden GA, Timmerman MF. A systematic review on the clinical efficacy of subgingival debridement in the treatment of chronic periodontitis. J Clin Periodontol 2002;29(3):5571.

Fleischer HC, Mellonig JT, Brayer WK, Gray JL, Barnett JD. Scaling and root planing efficacy in multirooted teeth. J Periodontol 1989;60:402409.

Brayer WK, Mellonig JT, Dunlap RM, Marinak KW, Carson RE. Scaling and root planing effectiveness: the effect of root surface access and operator experience. J Periodontol 1989;60:6772.

Wainwright M, Crossley KB. Photosensitizing agentscircumventing resistance and breaking down biofilms: a review. Int Biodeterior Biodegrad 2004;53:119-126.

Bhatti M, MacRobert A, Meghji S, Henderson B, Wilson M. A study of the uptake of toluidine blue O

by Porphyromonas gingivalis and the mech anism of lethal photosensitization. Photochem Photobiol 1998;68:370-376.

Wood S, Nattress B, Kirkham J, et al. An in vitro study of use of photodynamic therapy for the treatment of natural oral plaque biofilms formed in vivo. J Photochem Photobiol B 1999;50:17.

Castano AP, Demidova TN, Hamblin MR. Mechanisms in photodynamic therapy: part twocellular signaling, cell metabolism and modes of cell death. Photodiagn Photodyn Ther 2005;2:1-23.

K端bler AC. Photodynamic therapy. Med Laser Appl 2005;20:37-45.

10. Allison et al. Photosensitizers in clinical PDT. Photodiagnosis and PDT 2004;1:27-42.

11. Busch TM. Biophysical determinants of photodynamic therapy and approaches to improve outcomes. University of Peninsylvania, Philadelphia; 2006.

12. Steiner R. New laser technology and future applications. Med Laser Appl 2006;21:131-140.

13. Brown SB, Brown EA, Walker I. The present and future role of photodynamic therapy in cancer treatment. Lancet Oncol2004;5:497-508.

14. Tanaka M, Hanioka T, Takaya K, Shizukuishi S. Association of oxygen tension in human periodontal pockets with gingival inflammation. J Periodontol 1998;10:11271130.

15. Hamblin MR, Hasan T. Photodynamic therapy: a new antimicrobial approach to infectious disease?

Photochem Photobiol Sci 2004;3:436450.

16. Vaara M. Agents that increase the permeability of the outer membrane. Microbiol Rev 1992;56:395411.

17. Bertoloni G, Rossi F, Valduga G, Jori G, van Lier J. Photosensitizing activity of water- and lipid-soluble phthalocyanines on Escherichia coli. FEMS Microbiol Lett 1990;59:149155.

18. Bhatti M, MacRobert A, Henderson B, Shepherd P, Cridland J, Wilson M. Antibody-targeted lethal photosensitisation of Porphyromonas gingivalis.

Antimicrob Agents Chemother 2000;44: 26152618.

19. Soukos NS, Ximenez-Fyvie LA, Hamblin MR, Socransky SS, Hasan T. Targeted antimicrobial photo ch emoth erap y. A n timicro b A gents Chemother 1998;42:25952601.

20. Komerik N, Wilson M, Poole S. The effects of photodynamic on two virulence factors of Gram negative bacteria. Photochem Photobiol 2000;72:676680.

21. Packer S, Bhatti M, Burns T, Wilson M. Inactivation of proteolytic enzymes from P. gingivalis using light-activated agents. Laser Med Sci 2000;15:2430.

22. Valduga G, Breda B, Giacometti GM, Jori G, Reddi E. Photosensitization of wild and mutant strains of Escherichia coli by meso-tetra (N-methyl-4pyridyl)porphine. Biochem Biophys Res Commun 1999;256:8488.

23. Nitzan Y, Gutterman M, Malik Z, Ehrenberg B. Inactivation of Gram negative bacteria by photosensitized porphyrins. Photochem Photobiol 1992;55:8996.

24. Lauro FM, Pretto P, Covolo L, Jori G, Bertoloni G. Photoinactivation of bacterial strains involved in periodontal diseases sensitized by

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Photodynamic Therapy in Periodontics

porphycenepolylysine conjugates. Photochem Photobiol Sci 2002;1:468470.

25. Soukos NS, Hamblin MR, Hasan T. The effect of charge on cellular uptake and phototoxicity of polylysine-chlorine e6 conjugates. Photochem Photobiol 1997;65:723729.

26. Nitzan Y, Shainberg B, Malik Z. Photodynamic effects of deuteroporphyrin on gram positive bacteria. Curr Microbiol 1987;15:251258.

27. Pfitzner A, Sigusch BW, Albert V, Glockmann E. Killing of periodontopathogenic bacteria by p h o t o d y n a m i c t h e r a p y. J P e r i o d o n t o l 2004;75:13431349.

28. Nitzin Y, Shainberg B, Malik Z. The mechanisims of inactivation of staphylococcus aureus by deuteroporphyrin. J Curr Microbiol 1989;19:265269.

29. M i l l s o n C E , T h u r r e l l W, B u o n a c c o r s i G , WilsonM,MacRobert AJ, Bown SG. The effect of low-power laser light at different doses on gastric mucosa sensitized with methylene blue, haematoporphyrin derivative or toluidine blue.

Lasers Med Sci 1997;12:145150.

30. Jori G, Fabris C, Soncin M, et al. Photodynamic therapy in the treatment of microbial infections: basic principles and perspective applications. Lasers Surg Med 2006;38:468481.

31. Bertoloni G, Salvato B, Dall Acqua M, Vazzoler M, Jori G. Hematoporphyrin-sensitized photoinactivation of streptococcus faecalis.

Photochem Photobiol 1984;39:811819.

32. de Oliveira RR, Schwartz-Filho HO, Novaes AB, et al. Antimicrobial photodynamic therapy in the nonsurgical treatment of aggressive periodontitis: cytokine profile in gingival crevicular fluid, preliminary results. J Periodontol 2009;80:98105.

33. Chondros P, Nikolidakis D, Christodoulides N, Ro¨ ssler R, Gutknecht N, Sculean A. Photodynamic therapy as adjunct to non-surgical periodontal treatment in patients on periodontal maintenance: a randomized controlled clinical trial. Lasers Med Sci 2009;24:681688.

34. Braun A, Dehn C, Krause F, Jepsen S. Short-term clinical effects of adjunctive antimicrobial photodynamic therapy in periodontal treatment: a randomized clinical trial. J Clin Periodontol 2008; 35:877884.

35. de Oliveira RR, Schwartz-Filho HO, Novaes AB Jr, Taba M Jr. Antimicrobial photodynamic therapy in non-surgical treatment of aggressive periodontitis: a preliminary randomized controlled clinical study. J Periodontol 2007;78:965973.

Pictures

Fig. 1: when light (photon) of an appropriate energy is absorbed by a photosensitizer, which undergoes a transition from a low-energy ground state to the excited-singlet state. The activated photosensitizer interacts with oxygen to produce singlet oxygen and other radical species that cause a toxic effect in tumor cells or micro-organisms; ROS, reactive oxygen species.

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Review article

Microimplants in Orthodontics Tissa Francis1, George Menacherry2 1, 2. Senior Lecturer, Department of Orthodontics and Dentofacial Orthopaedics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram District, Kerala.

Correspondence: Tissa Francis, Senior Lecturer, Department of Orthodontics and Dentofacial Orthopaedics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram district, Kerala. e-mail: tissaf@rediffmail.com

Abstract All natural teeth are prone to movement in response to force application. Tooth or a group of teeth are united to counteract biomechanical reactive forces during orthodontic treatment. Anchorage plays an important role in the success of orthodontic treatment .In situations where the intraoral aids are limited in their anchorage potential, extra oral aids are chosen as an alternative to reinforce anchorage. As a result of advances in biocompatible materials, research has lead to the development of implants that have been successfully used in orthodontics for the purpose of anchorage control, thus satisfying a fundamental requirement of the treatment protocol.

This is a brief review on microimplants and its applications in orthodontics.

Key words : Anchorage, Microimplants, Biocompatible.

Introduction Conservation of anchorage in totality has been a perennial problem to the traditional orthodontist.

Clinicians continue to need anchorage that displays a high resistance to displacement.

However, Newton's Third Law states that a reaction for every action makes this difficult to achieve intraorally. Earlier, orthodontists used extraoral traction to reinforce intraoral anchorage. Nevertheless, patients seldom used headgears 24 /7, so this source of anchorage was often compromised.

Paradigms have started to shift in the orthodontic world since the introduction of mini-implants in the anchorage armamentarium. For example, miniscrews have allowed the management of wider discrepancies than those treatable by conventional biomechanics because force can be applied directly from the boneborne anchor unit. Therefore, miniscrews not only free orthodontists from anchorage-demanding cases, but they also enable clinicians to have good control over tooth movement in three dimensions.

By virtue of the success of implant inclusion in orthodontic treatment, a new class of anchorage strategy has arisen, and this class is known as 'Absolute Anchorage.’

Prosthodontic microimplants have been used as a source of absolute intraoral anchorage for some time.1 Dental implants used so far; however, have many

limitations due to their bulky size, the morbidity of associated surgery, and their relatively high cost. Thus, smaller diameter mini or microscrews, rather than bulkier dental implants, were introduced by Kanomi in 1997.2 Brane Mark (1964, 1969, and 1977) mentor of modern implant surgery described the high compatibility and strong anchorage of titanium in human tissue. The most significant development was the concept of 'osseointegration' put forth by Branemark in 1982. This served as the foundation on which the science of oral implantology is based upon.

Materials used for implants · Stainless steel · Cobalt-Chromium-Molybdenum Alloys · Titanium and its alloys: · Ceramics: Two types of ceramics can be distinguished · Bioactive Hydroxyapatite. · Bioglass These contain oxides of Ca, Na, P & Si

Microimplants in Orthodontics Conventional dental implants are 3.5-5.5mm in diameter and 11-21mm long. Microimplants are much smaller implants, suitable for orthodontic purposes in many ways. The microimplant is only 1.2mm in diameter

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Microimplants in Orthodontics

and 6mm long, making it much more useful in orthodontic applications.

Parts of an implant A commonly used implant screw has two parts; a) Implant head b) Implant body Originally microscrews were intended to be used for fixing small segments of fractured bone directly or to attach miniplates to bone in a surgical field. It proved difficult however to connect orthodontic attachments like elastic threads and elastomeric chains to the screw head of surgical miniscrews. Orthodontists compensated by placing a ligature wire on the cervical portion of the miniscrew by forming a connecting loop. These protocols often lead to periodontal involvement due to the location of the ligature wire.

To compensate for these drawbacks, new microimplants were introduced and designed specifically for orthodontic use.4 These microimplants have a button like head with a small hole to accept ligatures and elastomers as seen in Fig.2.

The smaller diameter of the implants allows its insertion into many areas of the maxilla and mandible thought previously unavailable, e.g between roots of adjacent teeth.

The predictable use of an implant as a source of anchorage for orthodontic tooth movement and orthopaedic corrections requires a practical understanding of the fundamental principles of bone biology and biomechanics.

Bone to Implant interface Modelling on the bone surface is the first osseous healing reaction following implantation of a biocompatible device into cortical bone. Similar to fracture healing, a bridge of callus forms at the periosteal and endosteal surfaces. Under certain conditions [minimal trauma and vascular compromise], the callus originates within a few millimetres from the margin of implantation site. A lattice of woven bone reaches the implant surfaces in about 6 weeks i.e. primary callus formation; while remodelling dependent maturation process, probably requires 3 times longer i.e. up to 18 weeks.

When the periosteum is stripped, the callus must originate in the nearest untraumatized osteogenic tissue.

Since healing reactions are self limiting, extensive loss of osteogenic [inner] layer may produce periosteal bridging altogether. A compromised osteogenic reaction,

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associated with a defect in the periosteal margin of bone, may favour invasion of the fibrous connective tissue. Extensive stripping of the periosteum substantially inhibits initial healing response. Hence, the surgeon should minimize periosteal trauma, consistent with adequate access and appropriate tissue management. The initial callus near the implant is primarily driven by local cytokines and growth factors. Remodelling of the callus begins in the healing period. According to the principle of adequate strength with minimal mass, the callus reduces in size and reorients as internal maturation and strength are attained.

Interface remodelling is essential in establishing a viable interface between the implant and original bone.

Despite optimal surgical technique, about a few millimetres of compact bone adjacent to the osseous wound die postoperatively, due to inflammation and relatively poor collateral circulation within the cortical bone. But it acts an important structural support during the initial healing phase. It is then replaced with vital bone via remodelling to strengthen the interface and providing adaptable tissue for long-term maintenance by cutting/ filling cones emerging from the endosteal surface oriented perpendicular to the long axis of the bone.

Maturation of the interface and supporting bone takes place in about 12 months and long-term maintenance of rigid osseous fixation involves continuous remodelling of the interface and supporting bone. The cortical bone around the implant continues to remodel enhancing the retention of the integrated implants.

Generally, mini-implants are without complete osseointegration. The union between the bone and implant surface is because of oxide layer which is formed around titanium implant and thus enhances the retention of non-osseointegrated implant these implants being generally porous in nature.

Surgical procedures for microimplant placement Terms used in microimplant surgical procedures: 1.

Path of microimplant insertion The microimplant is inserted into the bone in a direction oblique to the bone surface, 30 - 60째 to the long axis of the teeth (Fig.3). Such angulated placement reduces the risk of contacting the tooth root during implant placement.

2.

Head exposure Open method The head of the microimplant is exposed in the oral cavity. This is possible when placed in tight soft tissue such as the attached gingiva.

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Tissa Francis, George Menacherry

Mandible:

Closed method The head of the microimplant is embedded under soft tissue. This is done when placed in movable soft tissue.

3.

Site

Purpose

Size

Retromolar area

Uprighting molars Retraction of mandibular dentition

D- 1.4 to 1.6 mm L 5 to 10 mm

A. Self-tapping (Pre-drilling) method (fig. 4)

Between mandibular first and second molars buccally

Retraction of anteriors Intrusion and distal movement of molars.

D 1.3 to 1.6 mm L 5 to 7 mm

A tunnel is drilled into the bone first with a pilot drill, and then the implant is driven into the tunnel.

Between canine and premolars buccally

Protraction of mandibular molars

D 1.3 to 1.6 mm L 5 to 7 mm

Driving method

B. Self-Drilling method: (Fig.5) In this method, the implant itself acts as a drill as it is inserted into the bone. It can be used when larger diameter titanium implants are used.

Mandibular symphysis Intrusion of mandibular facially incisors

D 1.3 to 1.4 mm L 5 to 6 mm

Edentulous areas

D 1.3 to 1.6 mm L 7 to 8 mm

Anchorage, molar uprighting

The implant can be inserted into the bone either with Hand driver / with an engine driven screw driver.

Applications 6,10of micro implants in Orthodontics

Manual screw driver is of 2 types long and short.

Long handle driver is used for driving the microimplant buccally in both the arches. The short handle driver is used for driving the microimplant in the palate or retromolar area.

a.

Engine driven are available in four sizes depending on their length. When used, engine speed must be reduced to less than 100 rpm. A 256:1 speed reduction contra angle handpiece should be used with engine driven technique.5

Orthopedic Anchorage

· Maxillary Expansion · Headgear like effects b.

Dental Anchorage

· Space closure · Intrusion · Distalization · Simultaneous intrusion and retraction

Microimplant placement sites, sizes and purpose:5,10

· Torque control of maxillary anteriors

Maxilla

· Uprighting second molars9 Site

Purpose

Size

Infrazygomatic crest area

Retraction of entire maxillary dentition

Diameter 1.3 mm or 1.4 mm, length- 5 to 6 mm

Maxillary tuberosity area

Retraction of maxillary posterior teeth

D 1.3 to 1.5mm L -7 to 8 mm

Between maxillary Retraction of anterior first molar and second teeth Molar intrusion premolar buccally

D 1.2 to 1.3 mm L - 7 to 8 mm

Between maxillary incisors

D- 1.3 to 1.6mm Intrusion and torque control of the maxillary L 6 to 7 mm incisors

Between maxillary first molar and second premolar buccally and between first and second molar palatally

Anchorage in lingual orthodontics and for intrusion of molars in treating an open bite.

Midpalatal area

Any kind of tooth movement of the maxillary posterior teeth, unilateral constriction of the arch. Can be attached to a transpalatal arch for improving anchorage and distalising molars

D- 1.3 to 1.6mm L 10 to 12 mm

D 1.5 to 1.8 mm L 5 to 6 mm

· Forced eruption of impacted teeth

Removal of micro implant: Strong osseointegration does not occur between a micro implant and the adjacent bone. This lack of complete osseointegration facilitates microimplant removal. The clinician can engage the microimplant head with a hand driver and turn it in a direction opposite to that of insertion for easy removal.

Why micro implants?

Advantages of micro implant treatment 5 1.

Provides absolute anchorage for orthodontic tooth movement.

2.

Easily placed and removed. It takes only few minutes for each screw insertion.

3.

Does not depend on patient compliance as with extraoral appliances

4.

Produces an early profile improvement.

5.

Shortened treatment time by retracting anteriors simultaneously.

6.

Reduces chairside time.

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Microimplants in Orthodontics

Disadvantages of other absolute Anchorage systems

2. Kanomi R. Mini implants for orthodontic anchorage.

J Clin Orthod 1997;31:763 767.

1.

Cost

2.

Delay of the loading for several months

3. Creekmore TD, Eklund MK. The possibility of skeletal anchorage. J Clin Orthod 1983;17:266- 269.

3.

Location is limited by the morphology of the osseointegrating surface.

4.

Invasive surgery

Conclusion With the advent of microimplants, anchor loss is no more a nightmare to the orthodontist. Various difficult tooth movements can be carried out without taxing the adjacent or the anchor teeth. They help the Orthodontist to overcome the challenge of unwanted reciprocal tooth movement. The presently available implant systems are bound to change and evolve into more patient friendly and operator convenient designs. Long-term clinical trials are awaited to establish clinical guidelines in using implants for both orthodontic and orthopedic anchorage.

Proper use of mini implants requires a thorough knowledge of anatomical, biological, and biomechanical limitations.

Complete understanding of biomechanics and appropriate selection of mechanics will help to avoid few side effects which are intrinsic when implants are used.

References: 1. Smith JR. Bone dynamics associated with the controlled loading of bioglass- coated aluminium endosteal implants. Am J Orthod 1979;76:618- 636.

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4. Kyung HM, Park HS. Development of orthodontic microimplants for intraoral anchorage. J Clin Orthod 2003;37:321-328.

5. Jae Hun Sung, Hee- Moon Kyung. Brochure for the Absoanchor Orthodontic Microimplant. First ed.

2006.

6. Leung MT, Lee TC, Rabie AB, Wong RW. Use of miniscrews and miniplates in orthodontics. J Oral Maxillofac Surg. 2008;66(7):1461-1466.

7. Park HS, Bae SM, Kyung HM, Sung JH. Microimplant anchorage for treatment of skeletal Class I bimaxillary dentoalveolar protrusion. J Clin Orthod. 2001;35(7):417-422.

8. Roberts WE, Nelson CL, Goodacre C.J. Rigid implant anchorage to close a mandibular first molar extraction site. J Clin Orthod. 1994;28(12):693-704.

9. Park HS, Kwon OW, Sung JH. Uprighting second molars with micro-implant anchorage. J Clin Orthod. 2004;38(2):100-103.

10. B Melsen. Mini-implants: Where are we? J Clin Orthod 2005;39(9):539-547.

11. Wehrbein H, Glatzmaier J, Munwiller U, Diedrich P. The Orthosystem: A new implant system for orthodontic anchorage in the palate. J. Orofac.

Orthop 1996;57:143-153.

12. TM Graber, Robert L Vanarsdall. Current Principles and Techniques. 4th ed. St. Louis: Mosby; 2009.

13. William Proffit. Contemporary Orthodontics. 4th ed.

St. Louis: Mosby; 2007.

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Tissa Francis, George Menacherry

Pictures

Fig.1

Fig.4

Fig.2

Fig.3

Fig.5

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Review article

Torus in Disguise-Rare cases of impacted supernumerary premolars Rachana V Prabhu,1 Prasanna Kumar Rao,1 Laxmikanth Chatra,2 Prashanth Shenai3 1. Reader, 2. Senior Professor and Head, 3. Senior Professor, Department of Oral Medicine and Radiology, Yenepoya Dental College, Yenepoya University, Mangalore, Karnataka, India.

CORRESPONDENCE: Rachana V Prabhu, Reader, Department of Oral Medicine and Radiology,Yenepoya Dental College, Yenepoya University, Nithyananda Nagar Post, Deralakatte, Mangalore, Karnataka. e-mail: drrachanaacharya@rediffmail.com

Abstract A supernumerary tooth is the one that is additional to the normal series and can be found in any region of the dental arch but its occurrence in the lower premolar region is rare. A prevalence of around 8% of all supernumerary teeth has been reported in mandibular premolar region. Two case reports of impacted supernumerary teeth in mandibular premolar region presenting as a lingual swelling have been reported. An emphasis is given on the differential diagnosis of the most commonly seen lesions in this region.

Key words: Supernumerary premolar, Hyperdontia, Lingual swelling.

Introduction A supernumerary tooth is the one that is additional to the normal series. It is also called as Hyperdontia. A number of papers examining the prevalence of dental anomalies note a lower prevalence of supernumerary teeth than other developmental dental abnormalities.1 The occurrence of supernumerary teeth in the literature ranges from 1% to 6% in different population groups. Out of which 80 90% is present in the maxillary region with high prevalence rate in the maxillary anterior region, i.e. 70%.2 Supernumerary premolars have been reported to represent around 8.0% of all supernumerary teeth.3,4

Case Reports Case 1: A 20-year-old medically fit female patient reported to our dental clinic with a complaint of decay in relation to maxillary right first molar.

Intraoral examination revealed dental caries in relation to maxillary right first molar and a single, sessile, smooth surfaced bony hard swelling measuring approximately 1cm in its mediolateral dimension in relation to the lingual aspect of mandibular left premolar region [Fig. 1]. It was found to be non mobile and asymptomatic. No teeth were found to be missing in the region of swelling and all teeth were vital. No history of paraesthesia was noted.

Case 2: A 26- year- old medically fit male patient reported with a complaint of decay in relation to mandibular right first molar. Examination revealed root stumps in relation to mandibular right first molar and a single,

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sessile, smooth surfaced bony hard swelling measuring approximately 1cm in its medio-lateral dimension in relation to the lingual aspect of mandibular left premolar region [Fig. 2]. It was non mobile and asymptomatic.

There were no missing teeth in the region of the swelling and they were found to be vital. No history of paraesthesia was noted.

In both the above cases based on the clinical examination and considering the most common lesion occurring in this area a provisional diagnosis of unilateral mandibular torus was made. Cemento - ossifying fibroma, Odontoma and osteoma were considered in the differential diagnosis. Both the patients were advised Intra oral periapical (IOPA) radiographs which revealed a single impacted supernumerary premolar tooth in the mandibular left premolar region [Fig. 3&4]. Both patients were advised to undergo extraction of the impacted tooth.

Discussion The etiology of supernumerary teeth is not completely understood. Several theories have been suggested for the occurrence of supernumerary teeth.5 A hypothesis, well supported in the literature, is the hyperactivitytheory, which suggests that supernumeraries are formed as a result of local, independent, conditioned hyperactivity of the dental lamina.6 Supernumerary teeth are detected during first two decades of life. It exhibits a 2:1 male predominance.7 They may occur single, multiple or could be associated with the syndromes. One of the

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Rachana V Prabhu, Prasanna Kumar Rao, Laxmikanth Chatra, Prashanth Shenai

controlled study found that unlike other tooth abnormalities which may be significantly linked with other dental anomalies, supernumerary teeth appear to be a separate pathologic entity.8 They can be seen being present unilaterally or bilaterally in the maxilla, mandible or both.9 Single tooth hyperdontia occurs more frequently in the permanent dentition and approximately 90% present in the maxilla, with a strong predilection for the anterior region.7 Their morphology varies from conical, tuberculate, or supplemental. On the basis of their location they are called as mesiodens, paramolar and distomolar.9 These teeth can erupt normally, remain impacted, appear inverted or assume an ectopic position.10 Incidence of impaction of supernumerary teeth is found to be 15.1% which is much lesser than that found in a canine which is 59.6% and premolars i.e. 19%.11 The prevalence of supernumerary premolars in a generalpopulation is only 8%.3,12 Hence when the supernumerary teeth are found impacted in the lingual mandibular premolar region it mimics clinically as a mandibular torus. Other lesions to be considered for clinical differential diagnosis include cemento-ossifying fibroma, odontoma, osteoma, radicular cyst, ameloblastoma and odontogenic keratocyst (OKC).

Mandibular torus is a bony, exophytic growth along the lingual surface of the mandible, usually near the bicuspid teeth and above the mylohyoid ridge. It usually occurs bilaterally but about 20% of the cases represent unilateral presentation.7 The most common site for cemento-ossifying fibroma is mandibular premolar and molar area as seen in the present cases but these lesions are encountered during the third and fourth decade of life. Odontomas are more common in the maxilla and molar region. They have a marked tendency to involve the posterior body and ascending ramus.

Ostomas are more common in the body of the mandible or the condyle. When located in the body, most osteomas occur posterior to the premolar on the lingual surface.7 Presence of vital teeth and absence of paraesthesia helps in ruling out the lesions like radicular cyst and ameloblastoma respectively.

OKC has a tendency to grow in antero-posterior direction within the medullary cavity without causing bony expansion.7 Radiographic examination is very important in confirming the diagnosis.

In both the cases presented, the lesion was sessile, bony hard and asymptomatic thus causing a diagnostic dilemma.

Confirmation of the diagnosis was established using an IOPA radiograph.

Development of supernumerary teeth might precipitate a variety of complications such as crowding, delayed eruption, development of diastema, root resorption or rotation of adjacent teeth, cystic formation and compromised implant site preparation.5 Treatment generally includes extraction of these teeth.

In the present cases, although both patients were asymptomatic they were advised to go for extraction of the supernumerary premolars considering the possible future complications.

Conclusion Impacted supernumerary teeth should also be considered in the clinical differential diagnosis of lingual swellings. Radiographs play an important role in differentiating it from the other bony lesions and treatment planning. Early diagnosis and good treatment often are crucial in minimizing the esthetic and functional problems of the adjacent teeth.

References 1.

Brook A H. Dental anomalies of number, form and size: their prevalence in British schoolchildren. J Int Assoc Dent Child 1974;5:3753.

2.

Francinne MR, Andreia S, Italo MF. Impaction of Mandibular Molar by Supernumerary Tooth: Case Report. J Dent Child 2008;75:181-184.

3.

Nazif MM, Ruffalo RC, Zullo T. Impacted supernumerary teeth: a survey of 50 cases. J Am Dent Assoc 1983;106:201204.

4.

Kinirons MJ. Unerupted Premaxillary supernumerary teeth. A study of their occurrence in males and females. Br Dent J 1982;153:110.

5.

Farahani RMZ, Zonuz AT. Triad of Bilateral Duplicated Permanent Teeth, Persistent Open Apex and Tooth Malformation: A Case Report. J Contemp Dent Pract 2007;7:94-100.

6.

Liu JF. Characteristics of premaxillary supernumerary teeth: a survey of 112 cases. J Dent Child 1995;62:262265.

7.

Nevielle BW, Dam DD, Allen CM, Bouquot JE. Oral and Maxillofacial Pathology. 2nd ed. Saunders; 2005.

8.

Baccetti T. A controlled study of associated dental anomalies. Angle Orthod 1998;68:267274.

9.

Arora R, Acharya R, Mamatha GP, Arora SA. Mirror image of twin molars - a rariety-case report.

Clinical Dentistry 2010;8:57-59.

10. Y Refoua, M Arshad. An Unusual Case of Bilateral Maxillary and Mandibular Supernumerary Teeth.

Journal of Dentistry 2006;3:3.

11. Anastasia F, Athena K, Zaki B, Nikolaos P, Anastasios T. Incidence of impacted and supernumerary teetha radiographic study in a North Greek population. Med Oral Pathol Oral Cir Bucal 2011;16 :56-61.

12. Bateman G, Mossey PA. Ectopia or concomitant hypohyperdontia? A case report. Journal of Orthodontics 2006;33:71-77.

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Torus in Disguise Rare cases of impacted supernumerary premolars

Pictures

Fig. 1 Lingual Swelling in premolar region (Case 1).

Fig. 3 Impacted Supernumarary tooth (Case 1).

Fig. 2 Lingual swelling on left premolar region ( Case 2).

Fig. 4 Impacted supernumerary tooth (Case 2).

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Review article

Achondroplasia - A case report 1

2

Sham Kishor Kanneppady , Navaneetha Cugati , 3 4 Ramesh Kumaresan , Prasanna Kumar Rao 1. Lecturer, Department of Oral Radiology, Faculty of Dentistry, AIMST University, Malaysia.

2. Lecturer, Department of Pediatric Dentistry, Faculty of Dentistry, AIMST University, Malaysia.

3. Lecturer, Department of Oral and Maxillofacial Surgery,Faculty of Dentistry, AIMST University, Malaysia 4. Reader, Department of Oral Medicine and Radiology, Yenepoya Dental College and Hospital, Mangalore, India.

Correspondence: Sham Kishor Kanneppady, Lecturer, Department of Oral Radiology, Faculty of Dentistry, AIMST University, Semeling, 08100 Bedong, Kedah Darul Aman, Malaysia. e-mail: drsham.omr@gmail.com

Abstract Achondroplasia is by far the best known and commonest form of disproportionate short stature. It is inherited as an autosomal dominant manner, although in about 75% of cases it may be sporadic due to a new mutation. This type of dwarfism has been known for more than 5000 years, but it was not described as a clinical entity until 1851 and given a name in 1878. The diagnosis is suspected on physical examination and confirmed by different agerelated radiological features. Achondroplasia is of dental interest due to its typical oral and craniofacial features.

We present such a case in a 50-year-old female with emphasis on oral and craniofacial characteristics.

Keywords: Achondroplasia, Dwarfism, Craniofacial findings, Dental management.

Introduction

Case report

The term 'achondroplasia' was first used by Jules Parrot in 1878, and in 1900, Pierre Marie described the main features in children and adults. However, this condition was recognized earlier, as demonstrated in art from Egypt, Greece and Rome. As achondroplasia is the most common condition associated with disproportionate short stature, it is probably one of the best-known and defined chondrodysplasias.1 It is one of the most common forms of short-limb dwarfism, occurring in 1 of 25,000 births. 2 Achondroplasia is characterized by disproportionate short stature associated with enlarged head, short stubby trident hands, lordotic lumbar spine, prominent buttocks and protuberant abdomen.3 This autosomal-dominant disorder is caused by mutations in the type 3 receptor for fibroblast growth factor (FGFR3).

The natural history and management rules are well established in childhood and adolescence, but they are less fully delineated for adults, and several complications remain because of lack of preventative health.

A 50-year-old female patient reported to the Department of Oral Medicine and Radiology with the chief complaint of missing upper & lower teeth since two years. Extraction was done due to decay and mobility of teeth. Her past medical history revealed that she was diagnosed as having right thalamic hematoma with left ventricular hypertrophy (LVH), hyperlipidimia and hypertension. She was on medication for her cardiac abnormality and was consuming multivitamin tablets on daily basis. Patient had consulted dentists and underwent uneventful extraction of most of the teeth. There was no history of consanguineous marriage and other births in the family were normal. The patient's mother had noticed abnormal proportion of body parts of her daughter at the time of birth itself. Patient was conscious and cooperative and had normal intelligence. She possessed short stature altogether with large head and short limbs.

Her gait was altered but had normal posture. At the time of presentation, blood pressure was 170/130 mm of Hg, height 110 cm, weight 43 kgs and BMI was 36 Kg/m2 (Fig.1).

Achondroplasia is of dental interest because of its characteristic craniofacial features which include relative macrocephaly, depressed nasal bridge and maxillary hypoplasia. Presence of large head, implanted shunt, airway obstruction and difficulty in head control require special precautions during dental management. We present such a case in a middle aged female with emphasis on oral and craniofacial characteristics.

On extra oral examination, patient had normal sensory perception over the face. She had macrocephalic and brachycephalic head and her face was leptoprosopic.

The nasal bridge was depressed, profile was concave and lip was competent. Patient had retrognathic maxilla and prognathic mandible and TMJ showed slight clicking

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Achondroplasia - A case report

with deviated jaw opening (Fig.2 and 3). Only 5 teeth were present in jaw and all were periodontally compromised. Tongue was large and partially depapillated (Fig.4).

Considering the history and clinical examination, a provisional diagnosis of dwarfism due to achondroplasia was given. The differential diagnosis could be pituitary dwarfism, Cretinism, Rickets, Crouzon Syndrome, Treacher Collins Syndrome or Down Syndrome.

Panoramic radiograph showed severe bone loss with the existing teeth. Mandibular ramus and body were comparatively thinner (Fig.5). Lateral cephalogram revealed large calvarium, midface hypoplasia, retrognathic maxilla and prognathic mandible with class III skeletal malocclusion (Fig.6). Patient was referred to department of Oral Surgery for extraction of the remaining teeth and then to the department of Prosthodontics for complete denture prosthesis.

Discussion The birth incidence of achondroplasia is estimated to be between one in 10,000 and one in 30,000,4-7 affecting more than 2,50,000 individuals worldwide. It is one of the most common types of non-lethal skeletal chondrodysplasia. Earlier ascertainments of frequency were probably overestimates because, before involvement of the FGFR3 gene was identified, achondroplasia was often confused with various other chondrodysplasias.3 There is no racial predisposition.

Usually children with achondroplasia are identified early in life, at birth or shortly thereafter. With the advent of prenatal testing, it has become more common for the diagnosis to be made during fetal evaluation. In fact, the frequent use of prenatal ultrasonography has resulted in the diagnosis of approximately one third of all cases before birth.8 I n i n f a n t s a ff e c t e d b y a c h o n d r o p l a s i a , developmental milestones are delayed. Independent walking starts at an average of 16 months. Upper airway obstruction is secondary to mid-third facial hypoplasia Foramen magnum stenosis can cause cervicomedullary junction stenosis, which increases the risk of death in the first year of life. Thoraco-lumbar kyphosis is usually present, becoming more marked in a sitting child. This normally corrects without treatment once the child starts walking.9 In childhood, the fibulae are relatively long, which can cause bow leg deformity. Despite general joint laxity, the elbows tend to retain a mild flexion contracture. Tongue thrust in children may be related to the abnormal maxillomandibular relationship and malocclusion from disproportionate growth of the cranial

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base.10 Back pain is a common complaint from adolescence onwards and up to 17% will develop complications associated with spinal stenosis. The nature of short stature is disproportionate, with a mean adult height of 132 cm in males and 124 cm in females.

Increasing consciousness of stature difference leads patients to seek advice regarding leg lengthening. Life expectancy is normal after the first year of life and the risk of degenerative joint disease is low as the epiphyses are not affected.

In achondroplasia, complications are consequences of the abnormal linear bone growth. They can often be minimized if detected early. Indeed, guidelines for patients with achondroplasia have been developed in several countries10-13 to aid physicians in such preventive care. Regular follow-up by a trained multidisciplinary team may be essential to prevent or treat early neurological and respiratory complications, which arise particularly during the first year of life and in adults.

Orthodontic problems are found in more than half of cases, and are probably underreported in medical reports.10 Orthognathic surgeries followed by fixed orthodontic treatment are needed to achieve dental alignment. It is advised to perform dental treatment under local anesthesia, because general anesthesia poses certain complications due to anteriorly placed epiglottis, small nasal pharynx and larynx, difficulty in intubation, lumbar lordosis, narrowing of spinal cord and small chest.14,15 It is important for dental professionals, including pediatric dentists, orthodontists and oral surgeons treating these patients, to recognize risk factors and potential complications before sedation or anesthesia. When dental treatment is decided to be under general anesthesia, it is recommended to do radiologic evaluation of foramen magnum, preoxygenation before anesthesia, using appropriate endotracheal tube size, oral intubation and administration of oxygen after extubation.14

References 1.

Genevieve Baujat, Laurence Legeai-Mallet, Georges Finidori et al. Achondroplasia. Best Practice and Research Clinical Rheumatology 2008;22(1): 3-18.

2.

Orioli IM, Castilla EE, Barbosa-Neto, JG. The birth prevalence rates for the skeletal dysplasias. J. Med. Genet 1986;23:328332.

3.

Maroteaux P, Le Merrer M. L'achondroplasie. In: Maladies Osseuses de l'Enfant. Fammarion Medecine Science. 4th ed. Paris; 2002:5665.

4.

Oberklaid F, Danks DM, Jensen F et al.

Achondroplasia and hypochondroplasia.

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Sham Kishor Kanneppady, Navaneetha Cugati, Ramesh Kumaresan, Prasanna Kumar Rao

Comments on frequency, mutation rate and radiological features in skull and spine. Journal of Medical Genetics 1979;16:140146.

10. Hunter AGW, Bankier A, Rorers JG et al. Medical complications of achondroplasia: a multicentre patient review. J Med Genet 1998;35:705-712.

5.

Orioli IM, Castila EE, Scarano G et al. Effect of paternal age in achondroplasia, thanatophoric dysplasia and osteogenesis imperfecta. American Journal of Medical Genetics 1995;59:209217.

11. Trotter TL, Hall JG. American Academy of Pediatrics Committee on Genetics. Health supervision for children with achondroplasia.

Pediatrics 2005;116:771783.

6.

Stoll C, Dott B, Roth MP et al. Birth prevalence rates of skeletal dysplasias. Clinical Genetics 1989;35:8892.

12. Horton WA, Hall JG, Hecht JT. Achondroplasia.

Lancet 2007; 370:162172.

7.

Martinez-Frias ML, Cereijo A, Bermejo E et al.

Epidemiological aspects of Mendelian syndromes in a Spanish population sample: II. Autosomal dominant malformation syndromes. American Journal of Medical Genetics 1991;38:622625.

8.

Patricia T. Castiglia. Achondroplasia. J Pediatr Health Care 1996;10:180-182.

9.

Witherow PJ, Gargan MF. Management of rare and complex disability: achondroplasia and hypochondroplasia. Curr Paed 1996;6:178182.

13. Carter EM, Davis JG, Raggio CL. Advances in understanding etiology of achondroplasia and review of management. Current Opinion in Pediatrics 2007; 19:3237.

14. Kalla G, Fening E, Obiaya M. Anaesthetic management of achondroplasia. Br. J. Anaesth 1986;58:117119.

15. Butler MG, Hayes BG, Hathaway MM, Begleiter ML. Specific genetic diseases at risk for sedation/anesthesia complications. Anesth. Analg 2000;91:837855.

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Achondroplasia - A case report

Pictures

Fig. 2: Patient showing depressed nasal bridge, macrocephalic head

Fig. 4: Intra oral view showing large and partially depapillated tongue

Fig. 1: Short stature of the patient

Fig. 3: Patient showing concave profile and brachycephalic head

Fig. 5: Orthopantomogram showing severe bone loss, thinner body and ramus of mandible Fig. 6: Lateral cephalogram showing large calvarium, midface hypoplasia, retrognathic maxilla and prognathic mandible

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Case reports

Custom ocular prostheses: A clinical report 1

2

Ramya R , Balasubramanya Kv , Govindaraj SJ

3

1. Reader, Department of Prosthodontics. KGF College Of Dental Sciences, KGF, Karnataka.

2. Reader, Department of Periodontics. KGF College of Dental Sciences, KGF, Karnataka.

3. Reader, Department of Oral Medicine and Radiology. Al-Ameen Dental College, Bijapur, Karnataka.

Correspondence: Ramya R, Reader, Department of Prosthodontics. KGF College Of Dental Sciences, KGF, Karnataka. Email: ramyamohana@yahoo.co.in

Abstract Physical defects that compromise appearance or function, which prevents an individual from leading a normal life, usually prompt the individual to seek treatment that will restore acceptable normalcy.1 Orbital defects may be associated with congenital deformities, tumors, or acquired traumatic lesions and may affect the soft tissues within the orbital cavity or may include the surrounding muscles and bones.2 The fabrication of a definitive ocular prosthesis should begin as soon as the socket has healed. The custom ocular prosthesis is the immediate and feasible treatment option. This article describes the use of special tray and functional impression of socket with light body elastomeric impression material to impart accurate fit and functional movements of ocular prosthesis.

Keywords: Orbital defects, Irreversible hydrocolloid impression, Elastomeric impression, Custom Ocular prosthesis.

Intoduction

Procedure

The loss of an eye impairs the patient's visual function, also results in a noticeable deformity. This has a huge impact on the overall well being. Prosthesis should be provided as soon as possible to raise the spirits and ease the mind of the afflicted.

1.

An impression of the socket was taken with an ocular shaped impression tray according to the technique described by Allen and Webster.6 Irreversible hydrocolloid was mixed to a runny consistency by the addition of 1.5 parts water to 1 part powder. The impression material was injected into the socket. The operator supported the tray throughout the impression procedure, allowing the impression material to flow over the underlying muscle bed and the anatomic details to be recorded accurately (Fig.2). A cast was poured with dental stone. The tissue surface of socket was blocked with wax. An acrylic custom tray with perforations was fabricated to fit the socket without distorting the eye lids. A hollow tube was attached to the tray for entry of impression material. A modification of the technique described by Taicher et al7 was performed with the use of tray instead of prefabricated eyes as advocated by authors.

2.

The tray was inserted into the socket; light viscosity polyvinyl siloxane impression material (hydrophilic polyvinyl siloxane) was injected into the socket through the special tray. The patient was instructed to keep his head upright while performing eye movements with the natural eye.

The patient was instructed to move his natural eye in various directions until the impression material had set completely (Fig.3 and 4). A two-piece dental

Prosthetic rehabilitation is enhanced if an implant can be placed in the orbit to provide an attachment for the rectus muscles, which can impart motion coordinated with the natural eye.3 However the placement of an ocular implant is not always possible or feasible. Patients in this situation can be treated with custom-made ocular prostheses that have been adapted to accommodate specific situations.4 Impression materials used in dentistry such as impression waxes, irreversible hydrocolloids and elastomers can be successfully used to record the eye socket topography.5 An elastomer may be used to record the functional impression of an anophthalmic socket to fabricate custom made ocular prosthesis.

Case report A nine year old girl had an enucleation of right eye contents due to retinoblastoma which resulted in loss of eye (Fig.1). The patient was reluctant to undergo further surgery to place an implant, but she was anxious to have an ocular prosthesis made as soon as possible.

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Custom ocular prosthese -A clinical report

stone cast was poured to make a wax conformer.

The colour of patient's iris is matched with a stock ocular prosthesis. The sclera around the iris from the stock prosthesis is ground off. The iris is attached to wax conformer and is placed in the socket for evaluation.

3.

4.

The conformer was checked by placing into the socket for size, shape and contour (Fig.5). The conformer is used to fabricate a heat cure acrylic resin ocular prosthesis.5 Custom acrylic shade guide was made to match the sclera colour. Nylon veins were used to simulate blood vessels. Heat cure acrylic resin prosthesis was fabricated.

The finished prosthesis was inserted into the socket.

The prosthesis was extended to be in close contact with the remaining muscle fibres in the socket bed.

The functional impression technique allowed the artificial eye to move in unison with the patient's natural eye without being dislodged. This created a pleasing esthetic and functional result (Fig.6 and 7).

Discussion A correctly placed ocular prosthesis should maintain its orientation when the patient is looking straight ahead.

A correctly placed prosthesis should restore the normal opening of the eye, support the eyelids, restore a degree of movement, and be adequately retained and aesthetically pleasing. The use of a stock ocular prosthesis of an appropriate size and colour, adapted by selective grinding or additions of acrylic resin, has been advocated by Laney and Gardner.1 The custom ocular prosthesis provides close adaptation of prosthesis to tissue bed unlike stock prosthesis and distributes pressure more equally. The misfit between prosthesis and tissue interface is reduced and thus reducing the chance of fluid collection, tissue irritation and bacterial growth.

The incidence of conjuctival ulceration and abrasion is reduced.8 Standard techniques can produce excellent results for most patients, provided the operator has an adequate

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selection of prefabricated eyes. However, because of the extreme individual variation and diverse nature of ocular injuries, nature of ocular bed and need for close adaptation between prosthesis and tissues, patients would benefit more from custom ocular prostheses.

Conclusion The treatment of patient is described with standard technique for the fabrication of custom ocular prostheses. The outcome will eliminate the social stigma towards patients with head and neck defects. The prosthesis will reinforce the patient's attitude towards treatment and aid in confident and positive attitude. All patients with maxillofacial defects need to be rehabilitated to enhance quality of life.

References 1. Laney WR, Gardner AF. Maxillofacial prosthetics.

Littleton: P S G Publishing, 1979:255-89.

2. Ivy RH. Manual of standard practice of plastic and maxillofacial surgery. Philadelphia and London: W B Saunders, 1942;13:341-375.

3. Cain JR. Custom ocular prosthetics. J PROSTHET DENT 1982;48:690-694.

4. Sykes LM. Custom made ocular prosthesis a clinical report. J PROSTHET DENT 1996;75:1-3.

5. Ow.R.K.K. and Amrith S. Ocular prosthetics; use of tissue conditioner material to modify a stock ocular prosthesis. J PROSTHET DENT 1997;78:218-222.

6. Allen L, Webster HE. Modified impression method of artificial eye fitting. Am J Ophthalmol 1969;67:189.

7. Taicher S, Steinberg HM, Tubiana I, et al. Modified stock ocular prosthesis. J PROSTHET DENT 1985;54:95-98.

8.

Choy AE. Reconstruction of the head and neck.

B a l t i m o r e a n d L o n d o n : Wi l l i a m s & Wilkins,1981:219-238.

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Pictures

Fig. 1: Preoperative view.

Fig. 2: Irreversible hydrocolloid impression.

Fig.3: Acrylic tray in the socket.

Fig. 4: impression of socket.

Fig. 5: Wax conformer in place

Fig. 6: Post operative view

Fig 7: Movement of prosthesis with natural eye.

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Case reports

Nasal stent prosthesis - A case report Pramod sankar S1, Menon Prasad Rajagopal2, Rajitha A.V3 1. Senior Lecturer, Dept of Prosthodontics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala 2. Reader, Dept of Prosthodontics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala 3. Postgraduate student, Department of Oral medicine & Radiology, Government Dental College, Kozhikode, Kerala Correspondence: Pramod sankar S, Sr. Lecturer, Dept. of Prosthodontics, Educare Institute of Dental Sciences, Chattiparamba, Malappuram, Kerala. e-mail : sankar.pramod@gmail.com

Abstract Nasal stents may be utilised in a variety of ways in conjunction with reconstructive surgery. A case report, of a 13year old girl subjected to a secondary correction of nose is being presented describing the clinical and lab procedures involved in the fabrication of a nasal stent utilising auto-polymerizing acrylic resin.

Keywords: Stent, Prosthesis.

Introduction Usually cleft lip- cleft palate patients undergo early surgical correction. Often such patients have a nasal deformity which necessitates a secondary surgical correction. Nasal stents are devices that are inserted into the nose to prevent adhesion and thereby maintain its patency.

Nasal stents are used to 1. Provide support for the cartilage transplants during post-surgical healing for the correction of nasal deformities in cleft-lip patients.1 2. Maintain and minimize scar contracture following skin grafting procedures to the nostrils.2,3 3. Counteract previously formed scar tissue and widen the nostrils of trauma or burn patient prior to grafting procedures.

Case report A 13 year old girl with surgically corrected cleftlip patient, underwent a second surgery for nasal correction using cartilage transplant. She was referred from the Medical college, Calicut, for the fabrication of a nasal stent.

Procedure 1. Patient was seated comfortably in the dental chair in a semi-reclined position and briefed about the procedure.

2. The nasal hair were trimmed with a pair of scissors and the inner surface of the nares were coated with petroleum jelly/Vaseline.

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3. A flame and heated water bath was used to soften and temper sticks of modelling plastic impression compound (Green stick impression compound; DPI) (Fig.1).

4. Poly vinyl siloxane impression material (Provyl Novo) was injected over the impression compound and into and over the nose. Patient is asked to breathe through the mouth (Fig.2).

5. Bent pieces of 19-gauge stainless steel wire were embedded into the impression material before it is polymerized. After completion of polymerization, a layer of plaster (Model Plaster) was applied over the set impression (Fig.3).

6. After the plaster has completely set, the impression from patient's nose was gently removed and inspected for duplication accuracy (Fig.4).

7. The impression was poured with Type IV dental stone (Fig.5).

8. Separating medium (DPI) was applied to the definitive cast over the inner and outer surfaces of the nares.

9. The plastic housing of the syringe needle was cut to the required length and lightly coated with petroleum jelly.

10. Each tube was held in place and clear acrylic resin (DPI) added incrementally into each naris of the definitive cast to approximately half its volume.

11. A 19-gauge wire was bent over the columella and extended into the nares to embed into the resin before it is completely polymerised. Acrylic resin is added until the nares are filled.

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Pramod Sankar S, Menon Prasad Rajagopal, Rajitha A.V

12. After complete polymerization , the definitive cast was gently broken and the stent removed. The tube should be freely movable so that it can be easily removed.

13. All sharp edges were removed with a bur and stent finished and polished conventionally. The stent was inserted in position and checked for patent airway (Fig.6). A significant difference after wearing the stent was evident (Fig.7).

14. The patient was instructed to maintain good hygiene of the stent.

Conclusion It is simple, economical and comfortable to fabricate a relatively inconspicuous device which is retentive, aesthetic, functional and boosts the patient's self

confidence substantially.

References 1. Campbell TL, Duffy MB, Frame RT, Dorsett J. Use of a visible light curing resin material for the fabrication of an intranasal stent. Journal of prosthodontics 1993;nov70(5):483-485.

2. Lemon JC, Martin JW, Wesley PJ, King GE. Use of nonconductive tubing for nasal stent fabrication.

Journal of prosthetic dentistry 1994;mar71(3):301302.

3. Sharon-Buller A, Golender J, Savion I, Sela M. Technique for fabrication of splint preventing postsurgical restenosis in choanal atresia. Journal of prosthetic dentistry 2003;sep90(3):301-303.

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Nasal stent prosthesis - A case report

Pictures

Fig. 1 Sticks of modelling plastic impression compound (Green stick impression compound; DPI).

Fig. 2 Poly vinyl siloxane impression material (Provyl Novo) was injected over the impression compound and into and over the nose.

Fig. 3 A layer of plaster (Model Plaster) was applied over the set impression.

Fig. 4 The impression from patient's nose was gently removed and inspected for duplication accuracy.

Fig. 5 The impression was poured with Type IV dental stone.

Fig. 6 The stent was inserted in position and checked for patent airway.

Fig. 7 A significant difference after wearing the stent was evident.

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Case reports

Skeletal Class II correction with Twin Block Appliance - A case report 1

2

3

Shabeer N.N , Fawas Shaji , Reji Abraham , Pavithra U.S

4

1, 2. Postgraduate student 3. Reader, 4. Professor and HOD, Department of Orthodontics, Sri Hasanamba Dental College, Hassan, Karnataka.

Correspondence: Shabeer N.N, Postgraduate student, Department of Orthodontics, Sri Hasanamba dental college, Hassan, Karnataka. e-mail: dr_shabeer1981@yahoo.comSciences, Chattiparamba, Malappuram, Kerala. e-mail : sankar.pramod@gmail.com

Abstract Twin blocks may be either removable or fixed to the teeth and integrated with fixed appliance technique. For the correction of skeletal Class II malocclusion, the proper construction bite was taken and the models are articulated with the mandible in an advanced posh in. The amount of mandibular advancement depends on the ease with which the patient can posture forward. As a general rule, the initial activation should reduce the overjet by 5 to 7 mm leaving 3 to 5 mm interocclusal clearance in the first premolar region. The interocclusal clearance was increased where there was increased overbite and the bite blocks are designed to allow the free eruption of the lower molars to reduce the overbite by increasing the lower facial height. In thwas case report a 13 years old male patient with skeletal class II malocclusion was corrected with a Twin Block appliance.

Keywords: Twin Block, Bite blocks, Occlusal inclined plane.

causing the mandible to be dwasplaced downward and forward.2

Introduction Twin Block appliance was, developed by Dr. William J. Clark in Scotland. These appliances are simple bite blocks that are designed for full time wear. They achieve rapid functional correction of malocclusion by the transmwassion of favorable occlusal forces to occlusal inclined planes that cover the posterior teeth.

Because of the high percentage of patients presenting with Class II mandibular deficiency problems, orthodontwasts still are searching for the most effective means of stimulating mandibular growth preferentially.

Barring surgical lengthening of the mandible to correct mandibular retrognathia, functional appliances seem to be the most direct approach to the treatment of a mandibular deficiency problem.1 The goal in developing the Twin Block approach to treatment was to produce a technique that could maximize the growth response to functional mandibular protrusion by using an appliance system that was simple, comfortable and esthetically acceptable to the patient.

Twin Block was constructed with a protrusive bite that effectively modifies the occlusal inclined plane by means of acrylic inclined planes on occlusal bite blocks. The purpose was to promote protrusive mandibular function for the correction of the skeletal class II malocclusion.

The occlusal inclined plane act as a guiding mechanwasm

With the appliance in the mouth, the patient cannot occlude comfortably in the former dwastal position and the mandible was encouraged to adopt a protrusive bite with the inclined planes engaged in occlusion. Thwas case report gives an out look into the correction of skeletal class II malocclusion with a Twin Block appliance.2

Case report A 13 years old male patient presented to the Department of Orthodontics with the chief complaint of forwardly placed upper front teeth and backwardly placed lower jaw. Extra oral examination revealed a convex facial profile, mesocephalic head, mesoprosopic facial form, posterior facial divergen, incompetent lips with 5 mm inter labial gap, lip trap, with deep mentolabial sulcus with puckering in the chin (Fig.1) with a positive vwasual treatment objective (Fig.3).

Functional examination revealed normal deglutition, mastication, and speech. Respiration was nasal and hyperactive mentalwas muscle was noticed. No abnormality detected during temporomandibular joint examination. Intraoral examination showed normal soft twassue features. Molar relationship showed a Class II on left side and a dwastal end on relation on right side

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Skeletal Class II correction with Twin Block Appliance - A case report

and a scwassor bite in relation to right premolar region with an overjet of 10 mm and an overbite of 4 mm.

Upper midline was shifted towards right by 1.5mm (Fig.2). Cephalometric analyswas showed a normal maxilla and a retrognathic mandible in relation to anterior cranial base (Fig.4a). Hand wrwast radiograph represented skeletal maturity indicator (SMI) stage 3 with just 22% of adolescent growth completed (Fig.4c).

Diagnoswas A 13 year old prepubertal male patient with convex facial profile, incompetent lips, lip trap, normal maxilla and retrognathic mandible on a class II skeletal base with horizontal growth pattern with Angle's class II divwasion I malocclusion and scwassor bite in right premolar region.

into super class I. The maxillary appliance was incorporated with delta clasps on both first molars and a labial bow. The mandibular appliance incorporated delta clasps with ball end clasps between anteriors for better retention. The bite plane was constructed with 700 inclination with each other in both arches. Patient compliance was always a concern when treating patients with functional appliances. The Twin Block appliance has gained wide spread acceptance because it can be used as a removable functional appliance.

Treatment progress

The chief objective of thwas case was to improve the facial profile of the patient by correcting the retrognathic mandible. Other objectives included correction of molar relationship, lip trap, correction of increased overjet and scwassor bite in right premolar region.

Patient was instructed to wear the appliance full time and selective trimming of the maxillary bite block was carried out in occlusodwastal direction without touching the inclined plane. Trimming of the appliance was carried out followed by a retentive phase for settlement of occlusion (Fig.6). The active treatment time with the Twin Block appliance was 9 months.

Patient's facial profile improved significantly with the Twin block appliance therapy (Fig.7). After the functional phase of the therapy, patient underwent fixed orthodontic treatment.

Dwascussion

Conclusion

The occlusal inclined plane was the fundamental functional mechanwasm of the natural dentition. Cuspal inclined planes play an important part in determining the relationship of the teeth as they erupt into occlusion.

Occlusal forces transmitted through the dentition provide a constant proprioceptive stimulus to influence the rate of growth and the trabecular structure of the supporting bone. Fixed occlusal inclined planes have been used to alter the dwastribution of occlusal forces in animal experiments investigating the effects of functional mandibular dwasplacement on mandibular growth and on adaptive changes in the temporomandibular joint.

Rapid improvement in facial appearance was seen conswastently during the first few months of Twin block treatment. These changes were characterized by development of a lip seal and a noticeable improvement in facial balance and harmony.

Treatment objective

Functional protrusion of mandible was planned with Twin Block appliance (Fig.5) to reduce the skeletal and dental class II relationship as a first phase therapy and later fixed appliance therapy for dental correction. A construction bite had been regwastered in edge to edge relation; with 2mm interincwasal clearance and 8 mm mandibular advancement to get the molar relationship

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References 1.

Chrwastine M. Mills, Kara J. McCulloch: Treatment effects of the twin block appliance: A cephalometric study - American Journal of Orthodontics and Dentofacial Orthopedics 1998;114:15-24

2.

William J Clark: Twin Block Functional Therapy Application in Dentofacial Orthopedics. 2nd ed.

Toronto: Mosby; 2002.

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Shabeer N.N, Fawas Shaji, Reji Abraham, Pavithra U.S

Pictures

Fig.1 Pretreatment extra oral photographs

Fig.2 Pretreatment intra oral photograph

Fig.3 Vwasual treatment objective

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Skeletal Class II correction with Twin Block Appliance - A case report

Fig.4 (a-c) Lateral cephalogram, OPG, Hand wrwast radiograph

Fig.7 Post functional appliance treatment photograph

Fig.5 Twin Block appliance

Fig.6 Occlusion during the selective trimming of the appliance

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Others

'Health of the health care professional'Are we caring ourselves enough?

Navaneetha Cugati

1

1. Lecturer, Department of Pediatric Dentistry, AIMST University, Semeling, 08100, Bedong, Kedah Darul Aman, Malaysia.

Correspondence: Navaneetha Cugati, Lecturer, Department of Pediatric Dentistry, AIMST University, Semeling, 08100, Bedong, Kedah Darul Aman, Malaysia. e-mail: neetucugati@rediffmail.com

Abstract Mismatching factors between an individual and job stressors have a high probability of precipitating cumulative risks, especially among health care workers. This is termed as 'Professional Burnout Syndrome', which could compromise the empathetic elements of a caring profession. This article briefs on signs, symptoms, management, above all recognizing the problem; therefore suggesting strategies to ameliorate burnout risks, improve the quality of life and continuity of care.

Key words: Burnout, Work-related diseases, Depression, Stress.

Introduction In the light of social change and a transformation in the practice situation, the dental health care profession is becoming more acutely aware of the everyday stressors.

The effects of those stressors on a chronic condition, left unchecked are precipitated as “Professional Burnout Syndrome (PBS)”. This can be described as progressive loss of idealism, energy and purpose, experienced by people in the helping professions as a result of conditions of their work. Typically PBS is found in the professionals working in care service organization, characterized by low personal accomplishment, high emotional exhaustion and depersonalization. · Low personal accomplishment refers to the trend towards self-evaluation, especially affects their ability to do their work and the relationship with the people they are attending to and therefore reducing satisfaction in performance. · Feeling of emotional exhaustion refers to a situation due to daily and sustained contact with people they have to attend, as a matter of work. 'Burn-out' involves extreme physical and emotional exhaustion in which the professional loses positive feelings of sympathy and respect for the people whom they care. · Depersonalization is defined as the development of negative feeling and cynical attitudes and feeling towards the addresses of their work.

PBS has long been recognized as a problem that leaves once enthusiastic professionals feeling drained, cynical and ineffective, presenting with various complains and symptoms (Table 1).1 Most of the 'Victims' are not aware that some of the symptoms they might have experienced are the consequences of the so called Burn-Out Syndrome.

Paradoxally, the basic cause of stress, the work load, can become the only source of satisfaction for those experiencing burnout and separation from it can be very distressing. Unfortunately for these individuals, the symptoms of PBS may begin to more closely resemble a psychological mood disorder known as 'Dysthymia', a chronic, insidious, pervasive mood disorder characterized by long periods of low mood and impaired functioning.

Differentiating PBS and Dysthymia is very marginal by their symptoms. Like professional burnout syndrome, additional symptoms of dysthymia may include feelings of inadequacy, despair, irritability or excessive anger, guilt, generalized loss of interest or pleasure, social withdrawal, chronic fatigue or tiredness, decreased activity levels or productivity, and poor concentration.

Unlike the disabling functional symptoms normally associated with illnesses such as major depression, individuals affected by dysthymia generally suffer milder social and occupational dysfunction. For example, despite typical disturbances in their general interpersonal functioning, it is not unusual for

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'Health of the health care professional'-Are we caring ourselves enough?

dysthymics to work diligently in their profession and maintain a facade of normalcy2 but eventually, the chronic nature of dysthymia means that the disease will negatively impede the development and maintenance of professional relations with patients and professional colleagues. Thus, in addition to compromising close interpersonal relationships, dysthymia may result in the loss of valued employees and clientele. Thus adversely affect the quality of life of the dental health care professionals, with a reduction in job performance and stress related health problems.3

Management

路 Sometimes PBS and Dysthymia may require interventional professional help through Interpersonal psychotherapy (IPT). This was originally developed by Klerman and Weissman6 on a manual-based, time-limited (12 to 16 weeks) individual psychotherapy with strong research efficacy. Using four problem areas associated with depression (grief, interpersonal disputes, role transitions and interpersonal deficits), IPT treatment focuses on difficulties in interpersonal relationships.

However, it is important for health care professionals to recognize when they are at risk of crossing the threshold from stress into the world of professional burnout syndrome and dysthymia, which can pose as a major occupational hazard, seeking appropriate personal and occupational therapy.

PBS is therefore an occupational disease among health care professionals that must be recognized early and treated. Three major areas of stress for a health care professional that contribute to burn-out Depressive states Debility are; demands of the particular job, organizational factors and personal Feel of failure Self-Criticism characteristics of the individual.

Painful symptoms Fatigue Therefore intervention programs should Social isolation Drugs addiction concentrate on one or more of the following three main areas; self Problems with the rest of the team Poor concentration and performance management, organizational Less caring attitudes Irritability improvements, and the use of support Somatic complaints Suicidal ideation systems. Nevertheless, it is very Interpersonal problems Lack of Organization important to recognize the possible etiology and differentiate stress from Insomnia Spinal problems overwork and lack of motivation, as Table 1. Complains and symptoms of PBS: well as stress due to personal and situational factors. 路 The factors of individual subject change like engaging in a hobby or physical activity, having enough vacation time, recreational and religious activities can lower the risk of developing burnout to an extent. 路 Following measures can alleviate burn-out in an organization: Arranging different duties so as to suit best the individual capabilities.

Organizing a system of 'break' between duties, to diminish fatigue and tension.

Establishing a well-run and fair rotation system of duties. 路 For individuals diagnosed with dysthymia, antidepressant medicament such as Imipramine is an effective approach.4 But considering its side effects, non-specific activity and difficulty for the individual to experience their feelings and understand the source of their despair,5 it is not very much advisable.

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References

1. Astudillo W, Mendinueta C. Exhaustion syndrome in palliative care. Support Care Cancer 1996;4:408415.

2. Akiskal HS. Dysthymic disorder: psychopathology of proposed chronic depressive subtypes. Am J Psychiatry 1983;140:11-20.

3. Parker PA, Kulik JA. Burnout, self-and supervisorrated job performance and absenteeism among nurses. J Behav Med. 1995;18(6):581-599.

4. Kocsis JH, Frances AJ, Voss C, Mann JJ, Mason BJ, Sweeney J. Imipramine treatment for chronic depression. Arch Gen Psychiatry 1988;45:253-257.

5. Pollack R. Dental office ergonomics: how to reduce stress factors and increase efficiency. J Can Dent Assoc 1996;62:508-510.

6. Klerman GL, Weissman MM, Rounsaville BJ, Chevron ES. Interpersonal therapy of depression.

New York: Basic Books; 1984.

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Journal of Dento-Facial Sciences and Research An official publication of Academy of Dental sciences and Research About the journal

Manuscript preparation

The Journal of Dentofacial sciences and Research (JDSR) is a scientific journal dedicated to the dissemination of new knowledge and information on all science relevant to dentistry and to the oral cavity and associated structures in health and disease. The Journal is published biannually in the month of June and December.

The components of a manuscript should consist of title page, keywords, structured abstract, body of text, acknowledgements, references, illustrations (including legends) and tables.

Within the scope, the journal will publish the following articles:

The first page should include the title of the article (descriptive but brief and concise), the full names and professional/academic affiliations of all authors. Contact details including phone, fax and e-mail address must also be provided for the corresponding author, assumed to be the first listed author, unless otherwise advised.

1.

Original Research articles describing the results of clinical, laboratory and population-based research pertinent to dentistry and providing foundation knowledge for future application.

2.

Review articles presenting comprehensive, critical summaries of current knowledge and literature in the field of dentistry.

3.

Case reports illustrating various aspects of clinical practice including patient management.

4.

Materials and instruments reports on new products from the dental industry and its application

Title page

Authors Total number of authors should be limited to 4. Secondary contributors can be acknowledged at the end of the article.

Keywords Three to five keywords relevant to the article should be provided.

5.

Book reviews critical comments on recent publications, including electronic media.

6.

Conference reports proceedings of symposia, workshops or conferences.

A maximum of 250 word structured abstract (aim, materials and methods, results, conclusions).

7.

Letters to the Editor - regarding the issues related to recently published articles in the journal.

Body of text

8.

Others those articles which do not fall under the above mentioned categories.

Guidelines for author Manuscript Format Technical specifications: Manuscripts submitted to JDSR must be prepared in Microsoft Word. No manuscripts prepared in WordPerfect or other word processing software can be reviewed. Manuscripts prepared in Word 2007 must be saved down to Word 2003 format. Also, no illustrations or other material prepared in PowerPoint will be accepted for review. If your material was prepared in PowerPoint, please copy it into a Microsoft Word document.

Length - Unless otherwise noted above, manuscripts must be no longer than 10 double-spaced pages (roughly 3,000 words), exclusive of title page, abstract, acknowledgments, references and illustrations.

Abstract

i. Introduction, detailing the aim and scope of the paper ii. Major section, with subheadings, providing relevant background information, latest advances and the literature related to the topic; iii. Conclusions, summarizing the evidence and current knowledge as well as evaluating the clinical importance.

Acknowledgements Individuals who have made substantive contributions to the study should be acknowledged. Specify any grants or other financial support.

Illustrations (including legends) and tables Must be numbered and cited in the text in order of appearance and submitted electronically (illustrations must be at least 300 dpi). Each illustration and table (including its corresponding legend) must be on a separate page. Illustrations, tables, photographs,

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Journal of Dento-Facial Sciences and Research

radiographs must be scanned and submitted electronically.

Abbreviations The full term for an abbreviation should precede its first use in the text unless it is a recognized standard unit of measurement.

Trade names Generic terms are to be used whenever possible, but trade names and manufacturers should be included in parenthesis when first mentioned.

References All references must be cited in the text, using the Vancouver (numbered references) style. References should be marked in order of appearance with superscript numbers and listed numerically in the reference list at the end of the article. · Journal1. Lauterbach M, Martins IP, Castro-Caldas A, et al. Neurological outcomes in children with and without amalgam-related mercury exposure: seven years of longitudinal observations in a randomized trial. JADA 2008;139(2):138-145. · Book 2. Cohen S, Burns RC. Pathways of the pulp. 8th ed.

St. Louis: Mosby; 2002:196. · Book chapter 3. Byrne BE, Tibbetts LS. Conscious sedation and agents for the control of anxiety. In: Ciancio SG, ed. ADA Guide to Dental Therapeutics.

3rd ed. Chicago: American Dental Association; 2003:17-53. · Government publication 4. Medicine for the public: Women's health research.

Bethesda, Md.: U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health; 2001.

DHHS publication 02-4971. · World Wide Web site 5. Hoffman ED, Klees BS, Curtis CA. Brief summaries of Medicare & Medicaid: Title XVIII and Title XIX of the Social Security Act as of November 1, 2007. Baltimore, Md.: U.S. Department of Health and Human Services, Center for Medicare & Medicaid Services, Office of the Actuary; 2007. “Http://www.cms.hhs.gov/ MedicareProgramRatesStats/downloads/Medicare MedicaidSummaries2007.pdf”.

· Publication in press 6. McCoy J. Alteration in periodontal status as an indicator of general health. JADA (in press).

NOTE: Authors should double-check the status of any in-press work cited in their reference lists before submitting the final manuscript to JADA. · Presentation 7. Eichenstadt L, Brenner T. Caries levels among low-income children: report of a three year study.

Paper presented at: 146th Annual Session of the American Dental Association; Oct. 7, 2005; Philadelphia.

Editor's responsibilities Decision. Once the reviewers have completed their critiques, the editor examines their comments and makes a decision about the manuscript's disposition: accept, minor revisions, major revisions, or reject.

Editing. JDSR reserves the right to edit manuscripts to ensure conciseness, clarity and stylistic consistency and to fit articles to available space. After accepted articles are edited, they are returned to the authors for review and comment before publication. Authors will have the opportunity to review a PDF proof of their articles after they are typeset.

Author's responsibilities: Ethical approval: For clinical studies the approval of the relevant ethical committee must be obtained.

Contributor and Copyright form: mandatory submission of contributor's form and copyright form, signed by all authors must accompany the manuscripts before they can be reviewed for publication.

Adhearnce to guidelines: Manuscripts that are not prepared in accordance with these guidelines will be returned to the author.

Submission Manuscripts are to be submitted via e-mail as a word document to Editorjdsr@educareinstitute.in.

Illustrations can be attached in any format that can be opened using adobe photoshop (tif, gif, jpg, psd, eps etc.)

Mailing address Dr. Manjunath N. Chief editor, Journal of Dento-Facial Sciences and Research, Department of Oral Medicine & Radiology, Educare institute of dental sciences, College road, Chattiparamba, Malappuram district, 676 504 Kerala State, India

Accessed Aug. 28, 2008.

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