International Dentistry Australasian Edition - Vol.12 No.1

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VOL. 1 2 NO. 1 IN THIS ISSUE Satnam Singh Virdee Endodontic retreatment of a maxillary first molar

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Howard Gluckman and Jonathan Du Toit Consecutive treatment failures of an immediate maxillary canine implant and the subsequent replacement and reconstruction of the site Catiara Terra da Costa, Isadora Luana Flores, Fernanda Al-Alam, Manuela Souza e Silva, Priscila Martins, Thalita Goulart, Diana Tremea, Maria Laura Menezes Bonow The bow divider is an appropriate method to space measurement in mixed dentition by undergraduate students Shiehfung Tay and Nicola Di Vitale Biological width in the periodontic-restorative interrelationship Douglas Terry and Mark Stankewitz Simplifying composite placement in the interproximal zone Ricardo Machado, Gustavo Almeida, Thâmara Silva Santos, Brunna Presmini Barbosa, Guilherme Augusto Moreira and Alberto Porto Junior Pulp revascularisation in a traumatised and necrotic tooth Crispian Scully Making sense of mouth ulceration: Skin disorders

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Contents Volume 12 No. 1

4

Clinical

12

Clinical

Endodontic retreatment of a maxillary first molar Satnam Singh Virdee

12

Consecutive treatment failures of an immediate maxillary canine implant and the subsequent replacement and reconstruction of the site Howard Gluckman and Jonathan Du Toit

24 Clinical

The bow divider is an appropriate method to space measurement in mixed dentition by undergraduate students Catiara Terra da Costa, Isadora Luana Flores, Fernanda Al-Alam, Manuela Souza e Silva, Priscila Martins, Thalita Goulart, Diana Tremea, Maria Laura Menezes Bonow

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32 Clinical

Biological width in the periodontic-restorative interrelationship Shiehfung Tay and Nicola Di Vitale

42 Clinical

Simplifying composite placement in the interproximal zone Douglas Terry and Mark Stankewitz

52 42

Clinical Pulp revascularisation in a traumatised and necrotic tooth Ricardo Machado, Gustavo Almeida, Thâmara Silva Santos, Brunna Presmini Barbosa, Guilherme Augusto Moreira and Alberto Porto Junior

58 Clinical

Making sense of mouth ulceration: Skin disorders Crispian Scully

62 Products

VOL. 12, NO. 1 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION 1

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Stanley Bergman, CEO of Henry Schein, awarded Honorary Doctorate Stanley Bergman, Chairman and CEO of Henry Schein, has been awarded an Honorary Doctor of Commerce by the University of the Witwatersrand, Johannesburg, South Africa. A Wits alumnus, Bergman was recognised for his contribution to business, philanthropy and support for the arts, education and universities around the world.

Born in Port Elizabeth, South Africa, Bergman is admired for his stewardship of one of the world’s leading healthcare distribution companies.

He has combined his business success with the pursuit of social justice to help expand access to healthcare globally. Bergman, his medical specialist wife, Dr Marion Bergman - also a Wits alumna - and their two sons have made a difference to the lives of numerous people in the United States, Africa and many other developing regions in the world.

Bergman serves as a board member or advisor for many institutions, and is an honorary member of the American Dental Association and the Alpha Omega Dental Fraternity. He also holds many awards including an Honorary Fellowship of King’s College, London and the International College of Dentists.

Henry Schein Cares, the company’s global corporate social responsibility programme, has expanded access to healthcare for underserved and atrisk populations, as well as advancing diversity in the healthcare profession globally.

When asked to share the formula for his company’s success, Bergman says the following: “ Success is all about caring about people. The most successful, enduring business people and leaders in the world are the ones who care about people. I learned from my late mother growing up in Port Elizabeth that if you treat people how you want to be treated, things work out. From my late father I learned to always look for the good in people and be optimistic. I strongly believe that the more you give, the more you get back.

I’m not talking about getting back financially, I’m talking in terms of the inspiring people you meet and the enriching experiences you have.”

Vol. 12 No. 1 ISSN 2071-7962 PUBLISHING EDITOR Ursula Jenkins

EDITOR-IN-CHIEF Prof Dr Marco Ferrari

ASSOCIATE EDITORS Prof Cecilia Goracci Prof Simone Grandini Prof Andre van Zyl

EDITORIAL REVIEW BOARD Prof Paul V Abbott Prof Antonio Apicella Prof Piero Balleri Dr Marius Bredell Prof Kurt-W Bütow Prof Ji-hua Chen Prof Ricardo Marins de Carvalho Prof Carel L Davidson Prof Massimo De Sanctis Dr Carlo Ercoli Prof Livio Gallottini Prof Roberto Giorgetti Dr Patrick J Henry Prof Dr Reinhard Hickel Dr Sascha A Jovanovic Prof Ivo Krejci Dr Gerard Kugel Prof Edward Lynch Prof Ian Meyers Prof Maria Fidela de Lima Navarro Prof Hien Ngo Prof Antonella Polimeni Prof Eric Reynolds Prof Jean-Francois Roulet Prof N Dorin Ruse Prof Andre P Saadoun Prof Errol Stein Prof Lawrence Stephen Prof Zrinka Tarle Prof Franklin R Tay Prof Manuel Toledano Dr Bernard Touati Prof Laurence Walsh Prof Fernando Zarone Dr Daniel Ziskind PRINTED BY KHL PRINTING, Singapore

Professor Adam Habib, Vice-Chancellor and Principal of the University of the Witwatersrand, confers an Honorary Doctorate of Commerce on Stanley Bergman, Chairman and CEO of Henry Schein.

International Dentistry - Australasian Edition is published by Modern Dentistry Media CC, PO BOX 76021 WENDYWOOD 2144 SOUTH AFRICA Tel: +27 11 702-3195 Fax: +27 (0)86-568-1116 E-mail: dentsa@iafrica.com www.moderndentistrymedia.com

© COPYRIGHT All rights reserved.

No editorial matter published in International Dentistry Australasian Edition may be reproduced in any form or language without the written permission of the publishers. While every effort is made to ensure accurate reproduction, the authors, publishers and their employees or agents shall not be held responsible or in any way liable for errors, omissions or inaccuracies in the publication whether arising from negligence or otherwise or for any consequence arising therefrom.

Published in association with

Stanley Bergman Graduation ceremony.

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CLINICAL

Endodontic retreatment of a maxillary first molar Satnam Singh Virdee1

Introduction Mr DS, a 36-year-old photographer, was referred from his general dental practitioner (GDP) to the local restorative department for endodontic retreatment of a previously root filled maxillary first molar. This report aims to discuss the examination, treatment planning and endodontic management of this tooth, which present several complicating features.

History Presenting complaint – persistent dull pain arising from the upper right area of the mouth.

History of complaint – Mr DS complained of a well localised, moderate, but constant dull ache arising from the right maxillary first molar (UR6). This started nine months ago following an acute episode that was managed by his GDP with antibiotics and is exacerbated only by masticatory forces with no sensitivity to thermal stimuli.

The pain, which fortunately does not disturb his sleep, was being managed by overthe-counter analgesics.

He recalls that the tooth in question had previously undergone root canal therapy approximately nine years ago as a result of extensive caries. This was allegedly completed over a single visit, with no recollection of rubber dam use and, upon completion, was coronally restored with a direct restoration.

Relevant dental and social history – Mr DS regularly attends his GDP and has adopted an excellent oral hygiene regime, a low cariogenic diet, has never smoked and presents little to no anxiety or parafunction.

Relevant medical history – no relevant medical history or known drug allergies.

Examination – an extraoral assessment concluded a right submandibular lymphadenopathy.

Intraoral assessment • Soft tissues – nothing abnormal detected • Hard tissues – a moderately restored dentition with no evidence of caries (Figure 1) • Periodontal – BPE all 0s with very good oral hygiene and no mobility, recession or furcations • Occlusal – Class I incisors and group function on lateral excursions with no interferences.

1

Satnam Singh Virdee Restorative Dental Core Training post, Cardiff Dental Hospital, UK Part-time private practice, Birmingham, UK Figure 1: Dental charting.

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CLINICAL

Figure 2: Clinical photograph of UR6.

Figure 3: Preoperative long- cone periapical radiograph of UR6.

Right maxillary first molar assessment • Visual – a moderately sized mesiocclusal amalgam restoration with an intact mesial contact, but marginal ditching on the occlusal aspects. There was no evidence of caries, cracks, periodontal pocketing or mobility and approximately 60% of natural tooth structure remained (Figure 2) • Pulpal – repeated negative readings to electrical and thermal sensibility testing • Periodontal – no pocketing, mobility, recession or furcation involvement • Apical – moderate tenderness to apical percussion particularly on the mesiobuccal cusp tip. Although there was no apical swelling or sinus tract, on palpation there was tenderness on the attached buccal mucosa adjacent to the UR6 • Radiographic – an intraoral periapical radiograph taken using a long cone paralleling technique revealed a well corticated apical radiolucency greater than 5mm, associated with a significantly curved mesiobuccal root (>40o) and no evidence of MB2 instrumentation.

Additionally, the coronal restoration extends to the floor of the pulp chamber. Assessing against the quality guidelines, the previous root filling could be improved as it was poorly condensed and not extended to the appropriate length (European Society of Endodontology, 2006). Furthermore, there was a close anatomical relationship between the root apices and maxillary sinus (Figure 3).

a previous but infected root canal filling (Abbott, Yu, 2007).

Diagnosis Using the classification system set out by Abbot and Yu (2007), the diagnosis was chronic apical periodontitis with

Prognosis and treatment plan Ng et al (2011) reported the presence of a preoperative periapical lesion considerably reduced periapical healing and is a significant prognostic factor, which is consistent with landmark Toronto studies (Ng, Mann, Gulabivala, 2011a; Farzaneh, Abithol, Friedman, 2004). Additionally, it was found that the size of the apical lesion also had a statistical significance on treatment outcomes, with those less than 5mm healing more favourably as opposed to those that were larger (Ng, Mann, Gulabivala, 2011a).

Unfortunately, these features were all present in this case, reducing overall prognosis. However, the tooth also possessed several features that have been shown to improve treatment outcomes, such as the presence of a technically inadequate root filling, substantial natural tooth structure and adequate periodontal health with the absence of any perforations, sinus tracts or apically extruded root filling materia (Ng, Mann, Gulabivala, 2011a; Farzaneh, Abithol, Friedman, 2004).

The preoperative prognosis, therefore, was deemed slightly more favourably as ‘guarded’ and conveyed to the patient, as well as all relevant options, which included: • Leave • Orthograde retreatment • Referral to specialist endodontist • Extract and accept space • Extract and fill space.

Mr DS still wished to retain the tooth and agreed upon the following treatment plan:

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VIRDEE

Figure 4: Single tooth isolation of UR6.

Figure 5: Endodontic access.

• UR6 orthograde endodontic retreatment • Direct composite core and coronal restoration • Clinical and radiographic 12-monthly reviews.

Identifying canals

Treatment protocol First appointment Isolation and endodontic access Upon achieving profound anaesthesia, single tooth isolation was achieved using a winged molar clamp, rubber dam, floss and a caulking agent (Figure 4). The absence of any leaks into the oral cavity on water application from the triple air syringe confirmed a hermetic seal. Prior to access, the preoperative radiograph was studied closely to estimate the depth of the amalgam core restoration (Figure 3). A basic outline of an orthodox access cavity was then scribed into the amalgam surface and the predetermined depth was used to orientate a round-ended, tapered, cooled diamond bur during access to prevent causing iatrogenic injury. At the floor of the pulp chamber, a safe-ended tungsten carbide bur was used to remove the roof the pulp chamber, ensuring the minimally invasive access cavity permitted good visibility, was a reservoir for irrigants and straight-line access to all canal orifices.

Once access was gained, the pulpal floor was inspected for existing injuries and uninstrumented canals. Four canals were identified, three had been previously obturated and the MB2 was left uninstrumented. Estimated working lengths for each canal were established using the preoperative radiograph and then a glide path was established in the MB2 using ISO size 8-20 K-files and a Protaper Universal Sx file with lubricant (Figure 5; Table 1).

Gutta-percha removal The estimated length of gutta-percha (GP) was established from the preoperative radiograph. Gross GP was initially removed by a combination of Gates Glidden burs and Hedstrom files set to the length of GP. Fine remnants were then retrieved by introducing solvents into each orifice and using large paper points in a ‘wicking’ motion until all canals were patent and no further GP residue was visible on the terminal third of the paper points. Using an Electronic Apex Locator (EAL) and an ISO size 10 K-file, zero length readings for each canal were established (Table 1). For each reading, 0.5mm was subtracted to establish the true working length

Table 1: Estimated working length, zero length readings and true working lengths of all four UR6 canals Estimated working lengths

Zero length reading

True working lengths

(MM)

(MM)

(MM)

Mesiobuccal one

19mm to the MB cusp tip

20mm to the MB cusp tip

19.5mm to the MB cusp tip

Mesiobuccal two

19mm to the MB cusp tip

20mm to the MB cusp tip

19.5mm to the MB cusp tip

Distobuccal

22mm to the DB cusp tip

21mm to the DB cusp tip

20.5mm to the DB cusp tip

Palatal

25mm to the MP cusp tip

25mm to the MP cusp tip

24.5mm to the MP cusp tip

Canal

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VIRDEE

Figure 6: True working length radiograph.

Figure 7: Gutta-percha removed and all canals shaped.

Figure 8: Trial gutta-percha radiograph.

Figure 9: Obturated canals.

and then confirmed with a true working length long cone periapical radiograph (Table 1; Figure 6).

the critical component to a successful outcome. Following shaping, the tooth was temporised with non-setting calcium hydroxide paste and a distinctly coloured glass ionomer temporary restoration.

Chemomechanical debridement All canals were shaped to length using the Protaper Universal Rotary system with the mesiobuccal one, mesiobuccal two and the distobuccal canals shaped to an ISO 25 F2 and the palatal shaped to an ISO 30 F3. The varying taper of these files allowed the author to monitor shaping technique throughout the procedure. If carried out correctly, the shaper files should present with dentinal debris in the coronal aspect of the instrument, whereas this should be located in the apical region of finisher files (Figure 7).

All shaping was conducted in the presence of copious irrigation (sodium hypochlorite 5.5%) to aid removal of debris from the canal, lubricate files to prevent separation and to chemically disinfect the root canal system, which is

Second appointment Trial cone radiograph After regaining access and single tooth isolation, canals were dried using paper points followed and the respective GP cones were inserted to assess for tug back at the measured true working lengths. A trial cone periapical radiograph was then taken to confirm the shaping was completed to a satisfactory standard and to the correct length prior to obturation (Figure 8).

Irrigation activation Regardless of its many favourable properties, sodium

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VIRDEE

Figure 10: Direct composite coronal restoration.

Figure 11: Postoperative radiograph.

Obturation A warm vertical condensation technique was used to obturate the canals after the canals were thoroughly dried.

Initially, the GP was coated with a calcium hydroxide based sealer (AH+). When it was then inserted into the canal to length, the System B tip was activated to 5mm short of the true working length. At this length, the tip was deactivated and the excess coronal GP removed on withdrawal. The remainder of the canal was then obturated with thermoplastic GP in 2mm increments using the Obtura system (Figure 9).

Coronal seal Figure 12: 12-month post-operative radiograph.

hypochlorite is still unable to dissolve the inorganic component of the smear layer (American Association of Endodontists, 2011). This mineral film, which covers instrumented walls, can harbour residual microorganisms and impede the ability of sodium hypochlorite to penetrate deep into the dentine tubules, reducing its overall antimicrobial effect (Violich, Chandler, 2010). Therefore, to achieve a more thorough disinfection, a one-minute penultimate rinse of 17% EDTA was carried out upon completion of all mechanical instrumentation. This combination is a recognised technique and has shown to significantly improve the treatment outcomes of teeth undergoing endodontic retreatment (Ng, Mann, Gulabivala, 2011a).

With the smear layer now effectively removed, a final rinse of 5.25% sodium hypochlorite was administered. For each canal, a corresponding GP cone was inserted for manual dynamic activation of the irrigant before they were thoroughly dried and then finally obturated. Throughout the procedure, any change in solution was preceded by a saline flush to neutralise the effects of the former irrigant.

A definitive restoration was immediately placed after obturation, as Chugal et al (2007) reported those of a temporary nature result in higher failure rates. Initially, 3mm of flowable composite was used to seal the orifices of the canals and then a direct hybrid composite restoration was used to restore the lost tooth substance (Figure 10).

Although there was no mesial marginal ridge, a substantial amount of natural tooth structure was preserved and the remaining cusps retained a critical thickness of 2.5mm.

Additionally, the tooth was not at the terminus of the arch and was occlusally protected against excessive axial forces during excursive movements. These are all features that have been shown to improve the healing and longterm survival of the tooth and so a conservative direct composite coronal restoration was deemed appropriate (Polesel, 2011; Ng, Mann, Gulabivala, 2011b).

Following this, a postoperative periapical radiograph was taken to assess the quality of the endodontic root filling (Figure 11). This showed that the GP was obturated to the correct length; there were no voids, extrusions or overfills.

Additionally, the radiolucency does not appear to have increased in size.

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Review

Conclusion

At six and 12 months, Mr DS presented with no symptoms and had stated that there had not been any postoperative acute episodes. The tooth was now functional as he was able to eat on this side without feeling any pain.

Clinically, the coronal restoration was intact, and there was no evidence of active infection. Radiographic examination revealed the apical lesion had significantly reduced in size (Figure 12). Due to the absence of any symptoms and radiographic evidence of healing, the case was deemed as being successful and Mr DS was discharged back to his GDP and advised to be re-referred should any issues occur.

Overall, this case encompassed a combination of several complicating factors that challenged the author’s endodontic clinical skills and knowledge. The author has learnt to be insightful and critical of his own work, employ a systematic strategy to manage complications, and the value of using the literature to overcome challenges and develop as a clinician.

Discussion If the aim of root canal therapy is to resolve infection, then it could be assumed that the strict definition of endodontic success is to achieve complete resolution of apical periodontitis. This would mean that even in the absence of clinical symptoms and the presence of a comparatively reduced radiographic apical lesion, this case would still be considered a failure. However, it is well recognised that healing is a dynamic process that can take between two to five years to occur and an appropriate follow-up period is required to truly determine if success has been achieved (Eriksen, Ørstavik, Kerekes, 1988; Byström et al, 1987; Ørstavik, 1996). This is echoed in the quality guidelines, which recommend an annual follow-up period for up to four years, at which only then can failure be determined (European Society of Endodontology, 2006). Therefore, at this stage, describing outcomes dichotomously as a success or failure may not be representative of the dynamic healing process that is occurring.

However, one such classification system that does take this into account is the one set out by Friedman and Mor (2004) where endodontic outcomes are described as being either ‘healed’, ‘healing’ or ‘diseased’. The most appropriate term for this case would be ‘healing’ due to the absence of clinical symptoms and the significant reduction in the mesiobuccal periapical radiolucency at the 12-month review. This restoration of function would translate to an overall ‘good’ outcome and will require further review to assess if the well corticated apical lesion has completely healed, which would then become an ‘excellent’ outcome. Technically, the outcome meets all of the desirable criteria outlined in the quality guidelines and would be considered an ‘excellent’ outcome in this context (European Society of Endodontology, 2006).

Award-winning case Satnam Singh Virdee won the Young Dentist Endodontic Award 2016 for this case. Find out more at bit.ly/2jiuSLd.

References Abbott PV, Yu C (2007) A clinical classification of the status of the pulp and the root canal system. Aust Dent J 52:S17-31 American Association of Endodontists (2010) AAE Endodontic Case Difficulty Assessment Form and Guidelines [online]. Available at: <www.aae.org/caseassessment> [Accessed: 16/06/2016] American Association of Endodontists (2011) Root canal irrigants and disinfectants [online]. Available at: <bit.ly/2juUcwD> [Accessed 16/06/2016] Byström A, Happonen RP, Sjögren U, Sundqvist G (1987) Healing of periapical lesions of pulpless teeth after endodontic treatment with controlled asepsis. Endod Dent Traumatol 3:58-63 Chugal NM, Clive JM, Spångberg LSW (2007) Endodontic treatment outcome: effect of the permanent restoration. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 104: 576-582 Eriksen HM, Ørstavik D, Kerekes K (1988) Healing of apical periodontitis after endodontic treatment using three different root canal sealers. Endod Dent Traumatol 4: 114-117 European Society of Endodontology (2006) Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. Int Endod J 39: 921-930 Falcon HC, Richardson P, Shaw MJ, Bulman JS, Smith BGN (2001) Restorative dentistry: Developing an index of restorative dental treatment need. Br Dent J 190: 479-486 Farzaneh M, Abitbol S, Friedman S (2004) Treatment outcome in endodontics: the Toronto study. Phases I and II: Orthograde retreatment.

J Endod 30: 627-33 Friedman S, Mor C (2004) The success of endodontic therapy – healing and functionality. J Calif Dent Assoc 32: 493-503 Ng YL, Mann V, Gulabivala K (2011a) A prospective study of the factors affecting outcomes of nonsurgical root canal treatment: part 1: periapical health. Int Endod J 44: 583-609 Ng YL, Mann V, Gulabivala K (2011b) A prospective study of the factors affecting outcomes of non-surgical root canal treatment: part 2: tooth survival. Int Endod J 44: 610-625 Ørstavik D (1996) Time-course and risk analyses of the development and healing of chronic apical periodontitis in man. Int Endod J 29: 150– 155 Polesel A (2011) The conservative restoration of single posterior endodontically treated teeth. Ital J Endod 25: 3-21 Violich DR, Chandler NP (2010) The smear layer in endodontics – a review. Int Endod J 43: 2-15

Reprinted with permission by Endodontic Practice February 2017

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CLINICAL

Consecutive treatment failures of an immediate maxillary canine implant and the subsequent replacement and reconstruction of the site Howard Gluckman,1 Jonathan Du Toit2

Abstract Implant therapy is a valuable and reliable treatment in the restorative and reconstructive dentistry milieu. Many of the techniques employed are advanced and yet implant dentistry is routine in todayâ&#x20AC;&#x2122;s specialist and general dental practices.

The volume of treatment delivered though should never disregard the importance of thorough and concise treatment planning. A lack of knowledge and misapplication of fundamental implant therapy principles is demonstrated hereafter where an edentulous space at a missing maxillary canine was treated by an implant-supported crown, yet the complete failure of adequate treatment planning resulted in a bizarre clinical outcome requiring significant revisions to correct.

Paramount to the implant dentist and surgeon are the treatment planning principles highlighted by this case.

Keywords: Dental implant, implant therapy, treatment planning

Introduction

Howard Gluckman BDS, MChD (OMP) Specialist in periodontics and oral medicine, director of the Implant and Aesthetic Academy

1

Jonathan Du Toit BChD, Dipl.

Implantol., Dip Oral Surg, MSc Dent Department of Periodontics and Oral Medicine, School of Dentistry, Faculty of Health Sciences, University of Pretoria 2

The approach to treating an edentulous or partially edentulous jaw presents both clinician and patient with a clinical challenge addressed by several treatment options.1 Restorative implant treatment is among the more advanced options, and yet it is highly predictable and potentially very rewarding for the patient. Fundamental principles, though, are to be adhered to.2 Chief among these is thorough, concise, evidence-based treatment planning.3 The clinician is cautioned not to overlook the crucial importance thereof. All too often neglected are the most basic of examinations and thorough history taking. The reader may challenge him or herself, asking when last did I carry out a standard, full mouth periodontal examination to identify any periodontal disease that requires treatment before embarking on implant therapy?4 Thorough implant treatment planning almost always necessitates the use of special investigations and additional diagnostic aids. Whilst costly, the value of a cone-beam computed tomography (CBCT) scan to visualize the edentulous ridge or site in its 3dimensional aspects cannot be stressed enough.5 The treating clinician is to be cognizant of the recommended tissue parameters needed to support the dental implant and its restoration. The clinician is required to diagnose the need to augment these.6-8 The above-mentioned by no means addresses the entirety of the possible implant treatment planning aspects. However, the main shortcomings are highlighted, drawing attention to the case presented here and what led to the treatment failure.

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Figure 1: The preoperative presentation.

Figure 2: A draining sinus was noted buccal to the implant crown at 13.

Figure 3: Preoperative CBCT showed a dental implant with about half the body inserted into the nasal cavity, a root remnant buccal, and an angled abutment as long as the implant fixed to a crown restoration.

Figure 4: Full-thickness flap exposure of the site revealed an extensive buccofacial bony defect and soft tissue encapsulation of the implant abutment.

Case report

a period of healing. Subsequent to the chronic draining sinus buccal to the implant, the patient was advised by his general dentist to seek a third opinion. Clinical examination of the patient noted a screw-retained, implant-supported crown at site 13. Circumferential probing of the implant exceeded 15 mm, with bleeding upon probing, and exudate draining from a sinus midfacial at the implant site (Figs. 1, 2).

CBCT examination noted a custom abutment that extended about 8-10 mm in length, screw-retained to an external connection implant. The implant-abutment interface was positioned at approximately as deep as the root apices of the adjacent teeth, with about half the implant body penetrating into the nasal cavity (Fig. 3). There was also evidence of a root fragment adjacent to the implant. The extended custom abutment supported a cement-retained crown in the occlusal position. The mesial of tooth 14 had

A 21-year-old male presented with the main complaint of a persistent infection around an implant that had been placed about 1 year prior. The patient was a non-smoker, healthy, with a clear medical history and currently not taking any chronic medication. According to the patient’s history, the infection had persisted and the practitioner who placed the implant advised the patient the situation was not a problem.

The patient’s history entailed a retained deciduous canine with a congenitally missing tooth 13. The deciduous tooth was removed and an immediate implant was inserted at the site. The implant developed an infection and was removed.

A second implant was placed at the time of the first’s removal. This implant also became infected and was subsequently removed. The patient then saw a different practitioner who placed a third implant and restored it after

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Figure 5: Removal of the pathological soft tissue revealed the extent of the bony destruction.

Figure 6: The abutment was torqued to fracture, revealing an external hex connection implant.

Figure 7: The infective tissue at the implant and root remnant.

Figure 8: After removal, the restoration and abutment to implant ratio could be appreciated.

been reduced to accommodate the implant crown.

A detailed examination predicated the diagnosis of a severely malpositioned implant with a chronic peri-implantitis and unacceptable restoration. The treatment planning proposed removal of the implant and restoration, allowing for a period of healing and resolution of infection, and a reassessment of the siteâ&#x20AC;&#x2122;s treatment needs.

The site was anaesthetized and a full-thickness flap was raised over the implant at 13, exposing soft-tissue encapsulation of the abutment extending to the apices of the adjacent teeth (Fig. 4). The pathologic soft tissue was removed to send for histological examination, and the extent of the bony destruction at the area was exposed (Fig. 5).

Bone appeared eroded at the surfaces proximal to the implant. The buccal bone had a large defect yet the palatal bone remained coronal. The prosthesis and restoration were torqued and fractured from the implant and thereafter the implant torqued out (Figs. 6-8). The root fragment was also located and removed, the area meticulously debrided and

copiously rinsed with saline. Platelet-rich fibrin (PRF) membranes were placed within the defect and the site sutured closed with 6/0 nylon.

After 8 weeks of healing the edentulous site was reapproached and treatment planned from start. This included among many others a thorough clinical exam, periodontal examination, a holistic documentation of all pathologies and treatment needs, concise photographic documentation, study casts, restorative mock-up, and special investigative adjuncts including CBCT. The diagnostic list for the patient included a Class I malocclusion, recession defects, a mild fluorosis, and a missing 13. Diagnosing the healed, edentulous site at 13 noted a significant ridge defect, both horizontal and vertical, with a deficit of both hard and soft tissues. The soft tissue already showed significant scarring, recession distal to 12, and severe recession mesial to 14 with complete loss of the papillae (Figs. 9, 10). There was insufficient attached, keratinized tissue at the 14 with a Class IV recession defect.

The treatment planning entailed a bone augmentation of

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Figure 9: After initial healing of the site. Note the mesial of tooth 14 that was cut away. And the horizontal defect, as well as the extensive scarring is evident.

Figure 10: Tooth 14 was restored. Occlusal view accentuates the buccal defect.

Figure 11: Re-entry at the site illustrated the extent of the horizontal defect.

Figure 12: The radiographic-surgical guide in position and zenith of the pontic at the correct height. A severe vertical ridge deficit is not evident.

Figure 13: Placement via the guide confirmed a restoratively planned implant positioning for a screw-retained crown.

Figure 14: The implant fully inserted with an extensive buccal dehiscence that required augmentation.

the hard tissue defect, augmentation of the soft tissue deficit, and implant placement to restore with a screw-retained crown. Tooth 14 was first restored to re-establish a normal emergence profile and anatomy (Fig. 10). CBCT and virtual

implant planning indicated that implant placement in the restoratively correct 3-dimensional positioning with simultaneous augmentation with an autogenous corticocancellous bone block was a viable option. After local

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Figure 15: Harvesting of the ramus block.

Figure 16: The ramus block sectioned into two thinner grafts.

Figure 17: Bone shavings harvested by scraping and refining the block grafts.

Figure 18: The blocks fixed to the bony ridge buccal to the implant.

Figure 19: Buccal view of the bone blocks fixed in place.

Figure 20: The harvested autogenous bone shavings were packed beneath and around the blocks.

anaesthesia a full-thickness flap was again raised at the site and the implant osteotomy was prepared via a restorativeplanned surgical guide (Figs. 11, 12). A morse-taper, conical internal connection implant, 3.5 x 10 mm (NobelActive, Nobel Biocare) was inserted at the correct restoratively planned level, 2 mm below the palatal crest

(Figs. 13, 14). A corticocancellous bone block was then harvested from the left mandibular ramus, and split into two block veneer grafts as per Khouryâ&#x20AC;&#x2122;s protocol (Figs. 15, 16).9 The blocks were thinned with a bone scraper (Safescraper, Geistlich) further harvesting autogenous bone shavings (Fig. 17).

The blocks were then secured to the ridge buccal to the implant

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Figure 21: PRF membranes were layered atop the completed bone augmentation.

Figure 23: Immediate postoperative periapical radiograph.

This short, wide healing abutment is not ideal.

Figure 22: Site closure with 6/0 nylon sutures.

Figure 24: 12 weeks of healing.

Figure 25: CBCT scan showed the healed bone augmentation buccal to the implant 2.2 mm thick.

Figure 26: ISQ readings indicated high stability, positively confirming osseointegration.

with fixation screws, and the bone shavings packed within the defect between the implant and blocks (Figs. 18-20). PRF membranes were layered over the bone augmentation and the tension-free flap repositioned and sutured with 6/0 nylon (Figs.

21, 22). The site was then restored with a provisional partial denture free of pressure to the underlying augmentation site.

After 12 weeks of healing the implant was exposed and its implant stability quotient (ISQ) checked â&#x20AC;&#x201C; 78D 75M 75B

(Fig. 23-26). The buccal soft tissue was undermined by a tunneling approach, creating a split-thickness envelope. A connective tissue graft (CTG) was harvested from the palate and transferred into the pouch, sutured in position, thereby augmenting the soft tissue buccal and coronal to the site (Figs. 26-28). The implant was then restored with a provisional restoration to begin developing the soft tissue profile. At 4 weeks of healing a black triangle was evident

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Figure 27: The connective tissue graft (CTG) harvested from the palate positioned over the recipient site.

Figure 28: The implant exposed with CTG inserted and sutured inside a split-thickness tunnel flap.

Figure 29: 10-day follow-up with the provisional restoration in place. The soft tissue augmentation healing without complication.

Figure 30: 4-week follow-up, soft tissues healed, provisional in place, yet the absence of a distal papilla is obvious.

where the distal papilla was absent. A further 8 weeks of healing allowed time for soft tissue in-fill of the area (Figs.

28-31).

At final restoration of the implant a bulk of ridge tissue buccal to the implant could be noted, with near complete restitution of both mesial and distal papillae (Fig. 32).

Functional treatment goals were realized and adequate aesthetic rehabilitation of the previously failed treatment was achieved. The patient was satisfied, with the tissues and outcomes remaining stable at the 2-year recall (Fig. 32).

investigations where necessary, a review of the patientâ&#x20AC;&#x2122;s risk factors, all to derive accurate diagnoses.6, 16 It is evident from the failed case presented here that these principles were not adhered to. The site and its retained root were not diagnosed properly and thus the patient went through multiple and unnecessary procedures that ultimately required extensive reconstruction to rehabilitate the site. The ridge deficits were not diagnosed correctly and the need for bone and soft tissue augmentations was not identified. The value of a CBCT scan in planning implant treatment cannot be over-emphasized.14, 15, 17 Literature does not necessitate CBCT as an absolute for every implant treatment case planned, but it is difficult to identify a planned implant, verifying adequate bone circumferential to the implant, to locate anatomical structures of risk, to orientate a correct restoratively planned placement positioning.16, 18 Sound knowledge of implant dentistry principles are essential when delivering such treatment to a patient and the clinician is required to have a thorough understanding of anatomy, biology, prosthodontics, and implant hardware.

Discussion It is likely that with the ever-increasing availability of implant treatment, a greater number of implant procedures will produce increasing implant failure data.10, 11 Implant treatment has become commonplace in daily practice, yet the practitioner should never discount the importance of a correct approach and health care fundamentals.12-15 The foundation thereof is a comprehensive patient history, thorough clinical examination, the use of special adjunct

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Figure 31: A further 8 weeks allowed for soft tissue maturation and infill of the distal interproximal space.

Figure 32: The final screw-retained crown in place. Adequate bulk of tissue buccal to the implant restoration.

Figure 33: 2-year follow-up, tissues stable with adequate aesthetic and functional results.

Evident in the original failed treatment, a knowledge of the minimum bone required to accommodate the implant inserted at the correct height and position to ensure long-term tissue stability was lacking.6 Recognizing the need for a soft tissue augmentation that in turn supports healthy bone at the implant, that can be developed and sculpted to frame the implant restoration, potentially creating pseudopapillae as with the revised rehabilitation presented here, was also lacking.19 The attempt at placing a non-internal conical connection implant, and attempting to restore at occlusal level via a highly unconventional customized abutment contributed to the failure. Compromising established, evidence-based, reliable procedures and opting for an alternative compromise introduces a debate for clinical innovation versus jeopardizing treatment. But in this case the 3rd implant placement and restorative approach were both indisputably unacceptable. It is accepted clinical practice to

place an implant beyond the sinus or nasal floor cortex contained within an intact membrane and most often a bone augmentation, when a vertical ridge deficiency presents in the maxilla.20, 21 But entirely perforating into the nose, and placing a large portion of the implant body unsupported by augmented bone is not clinically acceptable and does not contribute to the integration of the implant. Of greatest concern in the case presented here was the disregard for principles of beneficence and non-maleficence.22 The persistent infection was not addressed and the underlying cause, likely the infected root fragment, was not diagnosed.

The failure of the previous two implant treatment attempts should have been investigated. Moreover, tooth 14 should not have been cut away to accommodate the implant restoration.

Managing increased crown height space to implant ratio is acceptable and common at resorbed, post-extraction sites.

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But extending a customized abutment transgingivally to bring the crown into occlusion as with this case is not acceptable.

The cantilever forces exerted in the failed treatment are not conducive to health.23 Moreover, the soft tissues when healed at the neck of an implant crown seek to establish a biological zone, commonly of long junctional epithelium with underlying connective tissue along the abutment.19 A tissue seal and attachment along the entirety of the failed abutment here was unlikely. As such, the long junctional epithelium may allow for bacterial plaque ingress and colonization along the length of the abutment that cannot be cleaned by the patient, resulting in the infective, granulation tissue seen at the implantâ&#x20AC;&#x2122;s removal.24

Conclusion A lack of sound knowledge in implant dentistry and an attempt at a compromise resulted in a drastic failure that required several additional procedures to rehabilitate. The failure presented here underpins the importance of basic and fundamental principles when approaching any treatment.

Key are proper examinations, diagnoses, and treatment planning, that substantiate ethical treatment options.

References 1. Misch CE. Chapter 21 - Single-Tooth Implant Restoration: Maxillary Anterior and Posterior Regions. Dental Implant Prosthetics (Second Edition). St. Louis: Mosby; 2015. p. 499-552.

2. Moraschini V, Poubel LA, Ferreira VF, Barboza Edos S. Evaluation of survival and success rates of dental implants reported in longitudinal studies with a follow-up period of at least 10 years: a systematic review. International journal of oral and maxillofacial surgery. 2015;44(3):377-88.

3. Thalji G A-TS. Prosthodontic considerations in the implant restoration of the esthetic zone. In: Sadowsky S, editor. Evidence-based Implant Treatment Planning and Clinical Protocols. Iowa: John Wiley & Sons; 2016. p. 109-22.

4. Cho-Yan Lee J, Mattheos N, Nixon KC, Ivanovski S. Residual periodontal pockets are a risk indicator for peri-implantitis in patients treated for periodontitis. Clinical oral implants research.

2012;23(3):325-33.

5. Du Toit J, Gluckman H, Gamil R, Renton T. Implant Injury Case Series and Review of the Literature Part 1: Inferior Alveolar Nerve Injury.

The Journal of oral implantology. 2015;41(4):e144-51.

6. Levine RA, Huynh-Ba G, Cochran DL. Soft tissue augmentation procedures for mucogingival defects in esthetic sites. The International journal of oral & maxillofacial implants. 2014;29 Suppl:155-85.

7. Puisys A, Linkevicius T. The influence of mucosal tissue thickening on crestal bone stability around bone-level implants. A prospective controlled clinical trial. Clinical oral implants research.

2015;26(2):123-9.

8. Urban IA, Jovanovic SA, Lozada JL. Vertical ridge augmentation using guided bone regeneration (GBR) in three clinical scenarios prior to implant placement: a retrospective study of 35 patients 12 to 72 months after loading. The International journal of oral & maxillofacial implants. 2009;24(3):502-10.

9. Khoury F, Khoury C. Chapter 6 - Mandibular bone block grafts:

Diagnosis, instrumentation, harvesting, techniques and surgical procedures. In: Khoury F, Antoun H, Missika P, Bessade J, editors. Bone Augmentation in Oral Implantology. London: Quintpub; 2007. p. 16983.

10. Derks J, Schaller D, Hakansson J, Wennstrom JL, Tomasi C, Berglundh T. Effectiveness of Implant Therapy Analyzed in a Swedish Population: Prevalence of Peri-implantitis. Journal of dental research.

2016;95(1):43-9.

11. Tarnow DP. Increasing Prevalence of Peri-implantitis: How Will We Manage? Journal of dental research. 2016;95(1):7-8.

12. Kuchler U, von Arx T. Horizontal ridge augmentation in conjunction with or prior to implant placement in the anterior maxilla: a systematic review. The International journal of oral & maxillofacial implants. 2014;29 Suppl:15.

13. Tahmaseb A, Wismeijer D, Coucke W, Derksen W. Computer technology applications in surgical implant dentistry: a systematic review. The International journal of oral & maxillofacial implants.

2014;29 Suppl:25.

14. Bornstein MM, Scarfe WC, Vaughn VM, Jacobs R. Cone beam computed tomography in implant dentistry: a systematic review focusing on guidelines, indications, and radiation dose risks. The International journal of oral & maxillofacial implants. 2014;29 Suppl:55-77.

15. Bornstein MM, Al-Nawas B, Kuchler U, Tahmaseb A. Consensus statements and recommended clinical procedures regarding contemporary surgical and radiographic techniques in implant dentistry.

The International journal of oral & maxillofacial implants. 2014;29 Suppl:78.

16. Buser D, Chappuis V, Belser UC, Chen S. Implant placement post extraction in esthetic single tooth sites: when immediate, when early, when late? Periodontology 2000. 2017;73(1):84-102.

17. Nunes LS, Bornstein MM, Sendi P, Buser D. Anatomical characteristics and dimensions of edentulous sites in the posterior maxillae of patients referred for implant therapy. The International journal of periodontics & restorative dentistry. 2013;33(3):337-45.

18. Harris D, Horner K, Grondahl K, Jacobs R, Helmrot E, Benic GI, et al. E.A.O. guidelines for the use of diagnostic imaging in implant dentistry 2011. A consensus workshop organized by the European Association for Osseointegration at the Medical University of Warsaw.

Clinical oral implants research. 2012;23(11):1243-53.

19. Linkevicius T, Apse P. Biologic width around implants. An evidence-based review. Stomatologija. 2008;10(1):27-35.

20. Mazor Z, Lorean A, Mijiritsky E, Levin L. Nasal floor elevation combined with dental implant placement. Clinical implant dentistry and related research. 2012;14(5):768-71.

21. Sanz M, Donos N, Alcoforado G, Balmer M, Gurzawska K, Mardas N, et al. Therapeutic concepts and methods for improving dental implant outcomes. Summary and consensus statements. The 4th EAO Consensus Conference 2015. Clinical oral implants research.

2015;26 Suppl 11:202-6.

22. Health Professions Council of South Africa. General Ethical Guidelines for the Health Care Professions [Online]. Pretoria: HPCSA; 2008 [updated 2008; cited 2017 19/01]. Available from: http://www.hpcsa.co.za/Conduct/Ethics.

23. Anitua E, Alkhraist MH, Pinas L, Begona L, Orive G. Implant survival and crestal bone loss around extra-short implants supporting a fixed denture: the effect of crown height space, crown-to-implant ratio, and offset placement of the prosthesis. The International journal of oral & maxillofacial implants. 2014;29(3):682-9.

24. Canullo L, Pellegrini G, Allievi C, Trombelli L, Annibali S, Dellavia C. Soft tissues around long-term platform switching implant restorations: a histological human evaluation. Preliminary results. Journal of clinical periodontology. 2011;38(1):86-94.

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The bow divider is an appropriate method to space measurement in mixed dentition by undergraduate students Catiara Terra da Costa,1 Isadora Luana Flores,2 Fernanda Al-Alam,3 Manuela Souza e Silva,3 Priscila Martins,1 Thalita Goulart,3 Diana Tremea,4 Maria Laura Menezes Bonow1 Abstract Background: The mixed dentition (MD) phase is dynamic and prone to disturbances in its normal development that might result in a decrease of the perimeter of the dental arch. None of the analyses of MD is sufficiently accurate, especially for undergraduate students. Objective: The objective of this study was to compare two measuring instruments used to determine the leeway space: brass wire (BW) and bow divider (BD), to verify whether the two methods are equivalent or whether one is more accurate for undergraduate students. Methods and Materials: Five undergraduate students from the Dental School, Federal University of Pelotas, and an orthodontist expert (the gold-standard) performed the measurement of leeway space using BW and BD on the inferior dental arch in thirty-five plaster models. A Bland-Altman and paired Student t test were used for statistical analysis. Results: Both methods showed statistical agreement. No significant statistical difference was obtained in the measurements of the BD method between the gold-standard and the students measurements. However, there was a difference between the gold standard measurements and two students' measurements using the BW method.

Discussion: The results show the high practicality and simplicity of the BD method. Conclusions: Both methods are equivalent when used by trained professionals, but the BD method is more accurate for undergraduate students. Clinical significance: The selection of a easily and reliable method for orthodontic measurements by beginner professionals.

Keywords: brass wire, bow divider, leeway space, measurements, mixed dentition Short Title: Bow divider is a method for undergraduate students

DDS, MSc, PhD Department of Social and Preventive Dentistry, Pelotas Dental School, Federal University of Pelotas, Brazil

1 1

DDS, MSc, PhD. Semiology and Oral Pathology area, Dental School, Federal University of Juiz de Fora, Brazil

2

3 3 3

DDS Manuela Souza e Silva, DDS, MSc Private dental clinic

4

Diana Tremea Undergraduate Student. Pelotas Dental School, Federal University of Pelotas, Brazil Corresponding Author: Dr Isadora Luana Flores Faculdade de Odontologia, Universidade Federal de Juiz de Fora – UFJF. Campus Governador Valadares, Avenida Doutor Raimundo Monteiro de Rezende, 330 – Centro, CEP 35010-173 Governador Valadares – MG Brazil. Tel.: +55 33 3340-0430 E-mail: isadoraluanaflores@gmail.com

Introduction The mixed dentition (MD) is a dynamic phase subject to disturbances in its normal development, its analysis being an important aspect for orthodontic diagnosis and treatment planning.1 The main perturbation in MD is the early loss of deciduous teeth leading to a decrease in arch perimeter and in space for the correct alignment of the permanent teeth, causing malocclusion.1 In orthodontic evaluation, the models of dental records are a main source of information as they allow a thorough assessment, complementary to the clinical examination.2 The plaster models are used to determine the relationship between the amount of available space in the dental arch (leeway space) and the amount of required space for the proper alignment of all permanent teeth.2,3 The bow divider (BD) and brass wire (BW) are recommended methods to analyze the leeway space through plaster models in MD.3 This space is determined by the available value in millimeters for the eruption of permanent teeth which are mesially positioned to the first permanent molars.3 The BD method evaluates the dental arch dividing the model in segments and the BW assesses the entire arch of the mesial molar to the other side.9 Due to the technical variability of both methods, the importance of evaluating an accurate, more practical and simpler measurement method is essential.

This effort can minimize the errors as well as the distortion of the results, and does not compromise the diagnosis, the treatment plan, and consequently the prognosis. The objective of this study was to compare two measurement tools, BW and BD, used to determine the leeway space in MD, and to verify whether the two methods are equivalent, and which is performed with greater accuracy by dentistry undergraduate students.

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Chart 1 - Bland-Altman plot of concordance analysis of measurements obtained by the gold standard. Mean difference: 0.17mm (p value = 0.0004¬).

Materials and methods This study was carried out at the Dental School of the Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil. Five undergraduate students and a professor of orthodontics performed two techniques of measuring the leeway space and the available space of the lower dental arch in plaster models. The methods used were BW and BD. Thirty-five plaster models of the lower dental arch of patients in the MD phase were selected from the archives of the orthodontic clinic of the Pelotas Dental School with no additional information. The models were identified by numbers from 01 to 35; the examiners were identified by capital letters: A, B, C, D, E, and gold-standard.

All examiners were supervised by the gold standard to perform the research. The dental arch was measured to evaluate the leeway space with the BW (0.027” inch diameter, Morelli) passing over the buccal cusps and incisor edges of the lower teeth from the mesial surface of the first permanent molar on one side to the mesial surface of the first permanent molar on the opposite side. The wire was bent and measured with a millimeter ruler. The values obtained were recorded on an annotation card. To evaluate the leeway space with the BD, the plaster model was divided into six sections: from the mesial contact point of the first permanent molar to the mesial of the first deciduous molar; from the mesial contact point of the first deciduous molar to the distal contact point of lateral incisor, and from the distal contact point of lateral incisor to the contact point between central incisors. The same areas were completed on the opposite side. All measurements were transferred to the annotation card and the sum of the values indicated the

leeway space.

Two separate measurements of the thirty-five plaster models were taken by the gold standard, and the average of each was calculated using both methods. These averages constituted the standard values which allowed the comparison between the two methods for the gold-standard themselves, as well as the comparison between the gold standard (professor of orthodontics) and other examiners (undergraduate students), in both methods. The gold-standard means were subjected to Bland-Altman statistical analysis to assess the agreement between the two methods, BW and BD. Using the paired Student’s t-Test, the comparison of the means of the measurements between the gold standard and the undergraduate students was analyzed. A significance level of 0.05 was considered for both statistical tests.

Results The measurements for the two methods obtained by the gold standard and the five examiners are shown in Table 1. The average values of the gold-standard for the BW and BD are shown in Table 2. No statistical difference was observed between the two methods for the gold-standard measurements (p=0.82). Moreover, a correlation of 99.4% was found between the two methods, with a mean difference of 0.17 mm (Chart 1 and 2).

No significant statistical difference was found between the measurements for the BD method between the gold-standard and undergraduate students. Nevertheless, with regard to the BW method, statistically significant differences were found between the specialist and two undergraduate examiners: C (value p = 0.0389) and D (value p =

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D A C O S TA E T A L Table 1 â&#x20AC;&#x201C; Measurements obtained by the examiners in thirty-five plaster models.

Model 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Measurement method Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire Bow divider Brass wire

Gold Standard 1st measurement 74.0 74.0 73.5 74.0 68.0 68.0 71.5 71.0 70.5 71.0 72.0 72.0 71.0 71.0 70.5 71.0 76.0 76.0 68.0 68.5 72.0 72.0 71.5 72.0 77.0 77.0 71.0 71.0 76.0 76.0 70.0 71.0 76.0 76.0 66.0 66.5 72.0 72.0 71.0 71.5 73.5 73.0 74.5 74.5 79.0 79.0 70.0 70.0 71.0 71.5 76.0 76.0 69.0 69.5 66.5 67.5 71.0 72.0 68.5 69.0 71.0 71.0 69.0 68.5 71.0 72.0 71.0 72.0 65.0 66.0

Gold Standard 2nd measurement 74.0 74.0 74.0 74.0 68.0 68.0 71.5 71.5 70.5 70.5 72.0 72.0 71.0 71.0 71.0 70.5 76.0 76.0 68.5 69.0 72.0 72.0 72.0 72.5 77.0 77.0 71.0 71.0 76.0 76.0 70.0 70.0 76.0 76.0 66.5 66.5 72.0 72.5 71.0 71.0 74.0 73.5 75.0 75.0 79.0 79.0 70.0 70.0 71.0 72.0 76.0 76.0 69.0 69.0 67.0 67.0 71.0 71.0 69.0 69.0 71.0 71.0 69.0 69.0 71.0 71.0 71.0 71.5 65.0 65.5

Examiner A

Examiner B

Examiner C

73.0 74.5 73.0 72.0 69.0 65.0 70.0 70.5 70.0 71.5 71.0 72.0 71.0 73.0 70.0 72.0 75.5 75.0 68.0 70.0 72.0 72.0 69.5 71.5 75.0 73.0 72.5 72.0 74.0 72.0 68.5 69.5 72.0 75.0 66.0 68.5 72.0 72.0 73.0 72.0 73.0 76.0 73.0 75.0 77.0 77.0 69.0 70.0 69.0 71.0 75.0 76.0 68.0 73.0 65.5 66.0 70.0 74.0 68.5 69.0 70.0 71.0 69.0 69.0 70.0 74.0 68.5 68.0 66.0 65.0

74.0 74.0 74.0 75.0 67.0 67.0 74.0 75.0 71.0 71.5 72.0 72.0 69.0 72.0 69.5 72.0 77.5 77.0 68.5 70.0 72.0 73.0 71.0 71.0 76.0 76.0 72.0 72.0 76.0 77.0 69.0 70.0 77.0 77.0 67.0 66.0 72.5 72.0 71.0 72.0 78.0 78.0 74.0 75.0 73.0 79.0 70.5 71.0 71.0 70.0 76.0 75.0 69.0 69.0 68.5 65.0 70.0 70.0 69.0 68.0 70.0 71.0 69.0 70.0 69.0 72.0 66.5 66.0 65.0 65.0

74.0 72.0 72.0 71.0 69.0 67.0 71.0 69.5 72.5 70.0 71.5 70.0 70.5 72.0 69.5 71.0 71.0 73.0 69.0 69.0 71.0 71.0 71.5 70.0 75.0 74.0 71.0 71.0 75.0 74.5 69.0 67.0 75.0 75.0 67.0 66.0 72.0 71.0 70.0 68.0 75.0 74.0 73.0 73.0 77.0 77.0 69.0 68.5 68.5 68.0 76.0 73.0 69.0 70.0 66.0 64.0 69.5 72.0 70.0 67.0 69.0 70.0 69.0 68.0 69.5 70.5 67.0 67.0 67.0 65.0

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Examiner D 74.0 72.0 73.0 70.0 71.5 68.0 68.0 69.0 70.0 69.0 71.0 69.5 70.0 71.0 71.0 68.0 74.0 73.0 68.0 67.0 72.0 70.0 70.0 69.0 73.0 73.5 72.0 69.5 75.0 72.0 69.0 68.0 72.0 73.0 66.0 64.0 73.0 70.0 71.0 68.0 73.5 73.0 74.0 73.0 78.0 76.0 67.5 68.0 69.0 68.5 74.0 74.0 67.5 68.5 66.0 65.0 69.0 70.0 68.0 66.0 70.0 70.0 69.0 68.5 69.0 71.0 66.0 67.0 65.0 63.0

Examiner E 73.0 75.0 72.0 72.0 67.0 67.0 70.0 70.0 70.0 72.0 70.5 71.0 70.0 79.0 69.0 72.0 75.5 74.5 69.0 69.0 71.5 71.0 69.0 70.0 75.0 73.5 70.0 72.0 75.0 73.0 69.0 69.5 74.0 75.0 65.0 65.5 71.0 71.5 71.0 70.5 72.0 70.0 72.0 74.0 76.5 80.0 69.5 69.5 68.0 69.0 76.0 76.0 69.0 69.0 65.0 64.5 70.0 72.0 67.5 66.0 70.0 70.0 69.0 68.0 71.0 73.0 68.0 68.0 63.0 65.5

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D A C O S TA E T A L

Table 2 - Average of measures obtained by Gold Standard (real difference in millimeters). T-Student test (p = 0.82).

Table 3 - Unpaired t-test difference of means of the gold standard and the examiners for bow divider and brass wire methods.

No

Bow Divider

Brass Wire

Difference

Examiner

Bow Divider (p)

Brass Wire (p)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

74 73.75 68 71.5 70.5 72 71 70.75 76 68.25 72 71.75 77 71 76 70 76 66.25 72 71 73.75 74.75 79 70 71 76 69 66.75 71 68.75 71 69 71 71 65

74 74 68 71.25 70.75 72 71 70.75 76 68.75 72 72.25 77 71 76 70.5 76 66.5 72.25 71.25 73.25 74.75 79 70 71.75 76 69.25 67.25 71.5 69 71 68.75 71.5 71.75 65.75

0 -0.25 0 0.25 -0.25 0 0 0 0 -0.5 0 -0.5 0 0 0 -0.5 0 -0.25 -0.25 -0.25 0.5 0 0 0 -0.75 0 -0.25 -0.5 -0.5 -0.25 0 0.25 -0.5 -0.75 -0.75

A B C D E

0.2440 0.7907 0.3224 0.1573 0.1067

0.8501 0.8946 0.0389 0.0027 0.3821

0.0027). Table 3 shows the measurements of the five examiners compared with the gold standard for both methods.

Discussion The diagnosis of perturbations in the MD is essential due to its transient and preceding role of MD before the permanent dentition characterized by occlusion maturation.2 Diverse events occur at this time, therefore prevention and interception of future malocclusions may be decisive. For this, it is possible to predict the course of the development of the occlusion by using specific methods for the analysis of MD since two or three millimeters of the real discrepancy may compromise the treatment plan.2

Based on the importance of choosing an accurate method of measuring the difference between the leeway space in the dental arches and the space required for permanent teeth eruption, different methods have been described in the literature.2,3,4 Nevertheless, there is no consensus about which is the most appropriate method; which one presents minimum systematic error; and whether both can be performed with equal safety by the novice and the specialist.5,6,7 Furthermore, no article in the English literature has previously compared these methods.

In the present study, the analysis of BW and BD, the most used daily tools in the undergraduate clinic, revealed no statistically significant difference between the two methods for the specialist. The difference between the two methods was 0.17mm which has no clinical relevance in relation to efficiency between the both methods. Thus, this concordance may be attributed to the experience and skill of the orthodontist, due to high training and frequent use of these tools.

However, the measurements from the BW method revealed a statistically significant difference between two undergraduate students in relation to the standard examiner. inexperience of the students in handling the brass wire correctly to get around the dental arch. Although the BW has been considered by some authors as the most efficient and reliable method of measurement,5 there are differences between the methods with regard to the ease of execution, an aspect that was evident in the present study. On the other hand, the measurements with BD did not show a statistically significant difference between the specialist and the students.

These results are in concordance with the findings obtained by other authors, indicating the high practicality and simplicity of this method.7 Thus, the most convenient method of learning the orthodontic process in the dental school might be the BD, due to easier handling by beginners.

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Chart 2 - Bland-Altman plot of concordance analysis. 99.4% of agreement.

Conclusion Although previous studies on topic are scarce in the English Literature, we considered that using the BD method of measuremnet is more accurate than the BW for undergraduate dental students. Thus, this method is recommended for less trained professionals in order to minimize errors in performing space measurement in orthodontics. However, it should be emphasized that both methods are equivalent to evaluate the leeway space through the plaster models of patients in the MD when performed by trained professionals.

Conflicts of interest The authors declare no conflicts of interest.

There are no funding sources that supported the current work.

References 1. Al-Bitar ZB, Al-Omari IK, Sonbol HN, Al-Ahmad HT, Hamdan AM. Mixed dentition analysis in a Jordanian population. Angle Orthod 2008;78:670-675.

2. Leal RC, Tanque IN, Gouveia SAS, Carmadella EG. Análise de modelos: uma revisão da literatura. Rev Clin Ortod Dental Press 2006;5:64-76.

3. Moyers RE. Handbook of Orthodontics. Chicago: Year Book, 1998.

4. Morrees CFA, Chada JM. Avaliable space for the incisors during dental development- A growth study based on physiologic age. Angle Orthod 1965;35:12-22.

4. Mucha JN, Bolognese AM. Análise de modelos em ortodontia. Rev Bras Odont 1985;42:28-44.

5. Nance HM. The limitations of orthodontic treatment. I – Mixed dentition diagnosis and treatkiuoment. Am J Orthod Oral Surg 1947;33:177-23.

5. Hoette F, Thomazinho A. Espaço presente do arco dental: análise crítica e comparativa. Ortodontia 1977;11:38-48.

6. Machado LA. Evaluation of two techniques to measure the available space in the mandibular dental arch using the method error. Rev Odonto Cienc 2012;27:228-32.

7. Vianna V, Amaral MT. Estudo comparativo entre dois métodos de medição do espaço presente no arco dentário para a dentição mista. Rev SOB 2002;4:34-38.

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Biological width in the periodonticrestorative interrelationship Shiehfung Tay1 and Nicola Di Vitale2

Restorative dentistry is considered successful only if the restorations are accompanied by surrounding healthy periodontium. It is widely known that restorative procedures interact with or are influenced by periodontal tissues, thus creating a bidirectional relationship that must exist in harmony.

As dental practitioners, we come across clinical cases where the biologic width is violated or abnormally distributed. This affects the aesthetic and also periodontal health, which then influences the success of the restoration and the longevity of the restored tooth. Increased aesthetic awareness among patients demands that the treatment we provide must also have an acceptable, if not optimal, long term result following the delivery of the prosthesis or completion of the crown lengthening surgery.

To understand how this has an impact on the restorative and surgical treatment planning, one has to have a comprehensive understanding of the core knowledge of the periodontium – specifically the dento-gingival interface (Figure 1). This inevitably brings us to biologic width.

Biologic width: definition and calculation

1

Dr Shiehfung Tay Senior Clinical Teaching Fellow and Research Associate, UCL Eastman Dental Institute, London, UK. Private Practice, London, UK

The term biologic width was introduced by D Walter Cohen in 1962, defining it as ‘the dimension of the soft tissue which is attached to the portion of the tooth coronal to the crest of alveolar bone’. Histologically, it includes the junctional epithelium and connective tissue attachment and it is synonymous to the sub-crevicular compartment described by Maynard and Wilson (1981). This supracrestal soft tissue attachment forms a seal, protecting the underlying alveolar bone from any insult originating from the oral environment.

The concept and clinical importance of biologic width cannot be emphasised enough particularly if crown lengthening surgery or any other restorative procedure is planned.

Although most studies reported average measurements that do not necessary apply in every case, they however do establish a guidance upon which clinical decisions are made (Sanavi et al, 1998).

One of the few ways of calculating biologic width is through transgingival probing (Table 1). This method, which is also known as bone sounding, is carried out under local anaesthesia with the use of a periodontal probe. Measurement can be influenced by many factors such angulation of the probing, precision of the probing instruments and distortion of the tissues during probing (Fu et al, 2010).

In a recent systematic review, the biologic width distribution of the general population ranged from 2.15mm to 2.30mm, although this showed intra- and inter-variability (Schmidt et al, 2013). Factors influencing this variability included: the type of tooth,

2

Dr Nicola Di Vitale Senior Clinical Teaching Fellow, UCL Eastman Dental Institute, London, UK. Private Practice, London, UK

Table 1: Calculating the biologic width Biologic width (x) = Transgingival probing (y) – Sulcular depth (z)

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Enamel Biologic width

Base of gingival sulcus

Junctional epithelium

Connective tissue attachment Alveolar crest

Figure 1: Bucco-lingual histologic specimen of healthy periodontium showing the components of dento-gingival junction.

Reproduced with kind permission from Dr MJ Novak et al (2008).

site, presence of restoration and periodontal status (for example, presence of periodontal disease).

According to Armitage et al (1977), inflammation allows probes to descend further into the sulcus and possibly penetrate the junctional epithelium as well as the connective tissue compartment. The biologic width dimension can be affected by periodontal disease, in both treated or nontreated cases (Schmidt et al, 2013).

A reduction of biologic width was observed in the presence of inflammation (Al-Rasheed et al, 2005), attachment loss (Gargiulo et al, 1961; Novak et al, 2008) and increased probing depth (Novak et al, 2008). It is vital that all tissues are inflammation-free before embarking on the restorative procedures.

Anterior versus posterior biologic width The next question of interest is probably: ‘Is there is a difference in the biologic width between anterior and posterior teeth?’ The answer is a resounding yes.

Vacek et al (1994) reported that the mean values were 1.75mm, 1.97mm and 2.08 for anterior, premolar and molar teeth respectively. However, Ghahroudi et al (2014) reported the values to be 1.46mm for anterior teeth and 1.63mm for posterior teeth.

The differences between these studies were thought to be attributed to the techniques used. For example, the former study used histomorphologic measurements while the latter

study employed transgingival probing.

Thick periodontium, which is normally found in posterior teeth, shows a higher biologic width and this validly explains the difference of the values between anterior and posterior teeth. The same study by Ghahroudi and co-workers confirmed this finding.

Biologic width violation Biologic width violation could be seen in fractures (Figure 2) or caries extending to gingival or subgingival margins, inappropriately-finished restorations (Figure 3) such as overhangs and overcontoured crown margins, restorative materials such as excess cement, and orthodontic devices.

Any factor that encourages plaque accumulation (Lang et al, 1983; Silness, 1970) or impedes cleaning leads to biologic width violation through inflammatory response (Table 2). Overhangs harbour microflora that is consistent with those observed in chronic periodontitis (Lang et al, 1983) and greater loss of attachment has been reported at sites corresponding to the overhang (Chen et al, 1987).

In this article, we will be focusing mainly on restorative margin placement and gingival retraction procedure.

Margin placement Margin placement generally falls into three types: supra-, suband equi- or paragingival. Whenever possible, supragingival or equigingival placement is advocated to favour the

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Figure 2: Disto-palatal fracture at UL2 extending subgingivally, causing localised gingival overgrowth as a response to the irritation.

Figure 3a: Violation of biologic width via subgingival placement of crowns on upper and lower incisors. Spontaneous gingival bleeding can be observed.

Figure 3b: Radiographic assessment revealed that the crown margins were inappropriately finished and were too close to the alveolar crest.

Figure 4: Crown lengthening surgery at UR1 to re-establish the 3mm distance from the alveolar crest to crown margin.

Figure 5: Splinted crowns at UR2-UR1 and UL1-UL2 with subgingivally placed margin.

These teeth showed not only severe chronic inflammation and loss of attachment but were also inaccessible to cleaning.

maintenance of periodontal health. Apart from better working and visual fields, supragingival margin placement also offers additional benefit such as ensuring that the preparation will be kept on enamel structure (Harish et al, 2015).

The interdental gingiva, a unique area composed of the facial and lingual papillae as well as the col, is always thicker than the facial or oro-gingivae. It is paramount to avoid the mistake of extending tooth preparation on all surfaces to one circumferential depth as this will inevitably violate the soft tissue attachment interproximally (Nevins and Skurow, 1984).

A systematic review by Akhlagi (2008) investigated the effect of crown margin position on periodontal tissue condition. It was confirmed that those reviewed studies were in agreement that subgingival placement of crown margin increases gingival inflammation although the depth of the crown margin extending into the intracrevicular crevice was not frequently reported.

Nevins and Skurow (1984) emphasised in their article that a safe distance of greater than or equal to 3mm from the alveolar crest to the crown margin should be allowed when the sulcus depth is considered to be 1mm (Figure 4).

It is impossible for clinicians to detect exactly where the sulcular epithelium ends and the junctional epithelium begins and therefore any subgingival margin should be considered as a compromise as more often than not it breaches the biologic width zone.

Sometimes, subgingival placement cannot be avoided and clinicians may need to extend the margin subgingivally to obtain more retention during the crown preparation or negotiate beyond caries and fracture line. It is also not unusual for clinicians to hide the margin of restoration subgingivally, hoping to achieve an optimal aesthetic result.

This could create a paradoxical result when, after a period of time, the crown margin becomes visible following gingival

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Figure 6: Bone loss at the furcation entrance of LL6 as a result of the violation of the biologic width following amalgam restoration.

recession due to the biologic width violation.

Any subgingival placement, if unavoidable, should be confined to 0.5mm to avoid disruption of the junctional epithelium and connective tissue apparatus during the restorative procedures.

Adverse effects (Figures 5 and 6) such as gingival inflammation, loss of attachment and bone resorption were noted when restoration margins were placed too close to the bone (Newcomb, 1974; Tal et al, 1989; Gunay et al, 2000).

Numerous studies have confirmed the importance of respecting the biologic width. When violation of this biologic width is detected, there is a need to re-establish this zone to ensure a harmonious periodontic-restorative interrelationship.

If there is a need to extend the restorative margin subgingivally beyond what is acceptable, or when reestablishment of the biologic width is required, then increasing the clinical crown structure by either crown lengthening surgery or orthodontic extrusion should be considered. This is aimed at exposing more tooth structure before proceeding with the final restoration.

According to the American Academy of Periodontology’s Glossary of Periodontal Terms, crown lengthening is: ‘A surgical procedure designed to increase the extent of supragingival tooth structure, primarily for restorative purposes, by apically positioning the gingival margins with or without the removal of supporting bone’.

Crown lengthening surgery is performed to fulfil aesthetic or functional requirement (Hempton and Dominici, 2010), or in some cases, both.

Indication for this procedure includes the need to negotiate beyond the subgingival caries or fracture and increase the retention form of a tooth. It can also be used for delayed passive eruption where there is an excess of gingival display.

Orthodontic extrusion is another technique for gaining clinical crown height by the means of orthodontic forced eruption in combination with a gingival fiberotomy as described by Pontoriero et al (1987). This could be a viable alternative when crown lengthening surgery is unsuitable or contraindicated.

Crown lengthening surgery in a multi-rooted tooth can be challenging even if this is in a non-aesthetic area. In a preliminary radiographic study by Dibart et al (2003), the critical distance from the crown margin to the furcation was assessed using radiographic measurements. Whenever crown lengthening surgery was carried out, it was found that 38.5% of those teeth developed furcation lesions after five years of crown cementation. Their results suggested that a minimum of 4mm from the crown margin to furcation is a prerequisite whenever crown lengthening surgery is carried out. Excessive bone removal that could result in exposing the furcation area is contraindicated.

Retraction cord placement One of the many ways of capturing the details of the subgingivally placed margin during impression is through gingival retraction. Development in dental materials saw old techniques such as copper bands phased out and replaced by cords impregnated with either 4% L-epinephrine or 25% aluminium chloride, foam or epoxy materials compound and elastic materials.

However, it must be remembered that the currently used cord technique can still cause trauma, leaving irreversible damage to the local soft tissues. Minimally invasive procedures that avoid trauma inflicted by the use of cords can be achieved by gingival retraction paste or gels such as Expasyl, which is universally accepted and widely used (Malbaker, 2010). According to Bennani et al (2012), the pressure generated by Expasyl is minimal and significantly lower compared to the cord system. However, it is because of this reduced mechanical pressure that many clinicians feel that it does not expose the margins adequately.

Duration, as well as the technique and material, is important and should not be overlooked. In 1990, Goodacre and his team found that there was a direct relationship between the time that the gingival retractor cord remains inside the sulcus and possible gingival recession.

They proposed that the junctional epithelium, which seals off the dento-gingival junction, was damaged during the procedure. In a dog study, Buttendorf et al (2015) showed that significant gingival recession was observed when retraction cord was left in situ for more than three minutes.

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Table 2: Interaction of periodontium to the violation and correction of the biologic width.

Wound healing following crown lengthening surgery The outcome of clinical crown lengthening is achieved through surgically-induced recession. Predicting the final position of the new gingival margin can sometimes be elusive, as it can be influenced by the positioning of the flap during the surgery as well as the duration of the healing period.

It is not uncommon to find that the new gingival margin continues growing coronally in what is considered as ‘creeping attachment’. This is also known as coronal displacement or rebound, and is found when the flap margin is positioned at the level of the osseous crest (Pontoreiro and Carnevale, 2001; Perez et al, 2007) during surgery. This was more pronounced amongst those with a thick gingival biotype (Pontoreiro and Carnevale 2001).

On the other hand, Deas et al (2004) noted that when the flap margin is placed at a more coronal level of the newlyestablished osseous crest, less rebound of the supracrestal soft tissue was observed.

It is therefore important to avoid excessive soft tissue resection but to allow primary closure during the flap adaption in this kind of surgery. Whenever an apically repositioned flap is utilised, the biological width reestablishes itself at an apical level (Oakly et al, 1999).

Another relevant aspect of the crown lengthening procedure is the duration of wound healing. The clinician needs to

understand when it is possible to proceed with the final impression. Since the final restorative margin depends on the position of the newly-created gingival margin, one needs to wait for the tissues to mature and stabilise following the surgery.

Although we routinely proceed to the final phase two months after the surgery, studies have suggested that a longer waiting period may be necessary – particularly in areas where aesthetics is a primary concern.

Bragger et al (1992) studied the periodontal changes during the healing phase after crown lengthening surgery.

Although the majority of the patients showed stability at six weeks to four months, 29% of the patients showed further recession while 33% showed coronal displacement or gingival creeping attachment.

Lanning et al (2003), Huynh (2007) and Shobha et al (2010), in accordance to Bragger’s study, agreed that a minimum of six months after surgical crown lengthening is needed for the tissue to stabilise further and the new biologic width to be re-established.

Conclusion In every restorative procedure, respecting the biologic width or re-establishing the violated biologic width is a key factor in ensuring a predictable outcome.

Any encroachment on the attachment apparatus can lead

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to detrimental effects on the periodontium. Inflammation of the soft tissue leads to the loss of attachment and in some susceptible individuals, this could potentially predispose them to periodontitis.

As inter- and intravariability exists, the dimension of the biologic width for each specific tooth and patient has to be assessed individually before any restorative procedure is carried out. One must consider crown lengthening surgery or orthodontic extrusion to correct the violated biologic width and provide an acceptable biologic width that is compatible with periodontal health. If dimensions are found to be insufficient, the most appropriate corrective procedure, whether surgical or orthodontic, can be undertaken for establishment of sufficient width.

References Akhlaghi F. (2008). Effect of crown margin position on periodontal tissue conditions. A systematic review and clinical interpretations (Master dissertation).

Retrieved from http://landalatandlakarna.se/documents/Master%20studie.pdf Al-Rasheed AA, Ghabban W, Zakour A (2005). Clinical biological width dimension around dentition of a selected Saudi population. Pak Oral & Dent J 25: 81-86 Armitage GC, Svanberg GK, Löe H (1977). Microscopic evaluation of clinical measurements of connective tissue attachment levels. J Clin Periodontol 4(3): 173-90 Bennani V, Aarts JM, He LH (2012). A comparison of pressure generated by cordless gingival displacement techniques. J Prosthet Dent 107(6): 388-92 Brägger U, Lauchenauer D, Lang NP (1992). Surgical lengthening of the clinical crown. J Clin Periodontol 19(1): 58-63 Buttendorf AR, Ferreira CF, Bianchini MA, Da Silva JE, Wicks RA (2015) Minimal Time for Gingival Retraction Cords to Achieve Accurate Impression: An In Vivo Study. J Dent Health Oral Disord Ther 1(3): 78 Deas DE, Moritz AJ, McDonnell HT, Powell CA, Mealey BL (2004).

Osseous surgery for crown lengthening: a 6-month clinical study. J Periodontol 75(9): 1288-1294 Dibart S, Capri D, Nunn ME, Van Dyke TE, Kachouh I (2003). Crown lengthening in mandibular molars. A 5 year retrospective radiographic analysis. J Periodontol 74: 815-821 Fu JH, Yeh CY, Chan HL, Tatarakis N, Leong DJ, Wang HL (2010).

Tissue biotype and its relation to the underlying bone morphology. J Periodontol 81(4): 569-574 Gargiulo AW, Wentz FM, Orban B (1961). Dimensions and relations of the dentogingival junction in humans. J Periodontol 32: 261-7 Goodacre CJ (1990). Gingival esthetics. J Prosthet Dent 64(1): 1-12 Gunay H, Seeger A, Tschernitschek H, Geurtsen W (2000).

Placement of the preparation line and periodontal health--a prospective 2-year clinical study. Int J Periodontics Restorative Dent 20: 171-81 Harish P, Joseph SA, Sirajuddin S, Gundapaneni V, Chungkham SA (2015). Iatrogenic Damage to the Periodontium Caused by Fixed Prosthodontic Treatment Procedures. The Open Dentistry Journal 9: 190-196 Hempton TJ, Dominici JT (2010). Contemporary crown-lengthening

therapy: a review. J Am Dent Assoc 141(6): 647-55 Huynh G (2007). Surgical crown lengthening of the clinical crown: A periodontal concept for reconstructive dentistry. J Periodontol 3: 193-201 Lang NP, Kiel RA, Anderhalden K (1983). Clinical and microbiological effects of subgingival restorations with overhanging or clinically perfect margins. J Clin Periodontol 10: 563-578 Lanning SK, Waldrop TC, Gunsolley JC et al (2003). Surgical crown lengthening: evaluation of the biologic width. J Periodontol 74: 468-474 Malbaker AM (201). Gingival retraction—Techniques and materials: A review. Pak. Oral Dent J 30: 545–551 Maynard JG, Wilson RD (1979). Physiologic dimension of the periodontium fundamental to successful restorative dentistry. J Periodontal 50(4): 170-4 Nevins M, Skurow HM (1984). The intra-crevicular restorative margin, the biologic width, and the maintenance of the gingival margin. Int J Periodontics Restorative Dent 4(3): 30-49 Newcomb GM (1974). The relationship between the location of subgingival crown margins and gingival inflammation. J Periodontol 45: 151-4 Novak MJ, Albather HM, Close JM (2008). Redefining the biologic width in severe, generalized, chronic periodontitis: implications for therapy. J Periodontol 79(10): 1864-9 Oakley E, Rhyu IC, Karatzas S, Gandini-Santiago L, Nevins M, Caton J (1999). Formation of the biologic width following crown lengthening in nonhuman primates. Int J Periodontics Restorative Dent 19(6): 529-541 Perez JR, Smuckler H, Nunn ME (2007). Clinical evaluation of the supraosseous gingivae before and after crown lengthening. J Periodontol 78(6): 1023-1030 Pontoriero R, Carnevale G (2001). Surgical crown lengthening: a 12month clinical wound healing study. J Periodontol 72(7): 841-848

Pontoriero R, Celenza F Jr, Ricci G, Carnevale G (1987). Rapid extrusion with fiber resection: A combined orthodontic-periodontic treatment modality. Int J Periodontics Restorative Dent 7(5): 31-43 Rasouli Ghahroudi AA, Khorsand A, Yaghobee S, Haghighati F (2014). Is biologic width of anterior and posterior teeth similar? Acta Med Iran 52(9): 697-702 Sanavi F, Weisgold AS, Rose LF (1998). Biologic width and its relation to periodontal biotypes. J Esthet Dent 10(3): 157-63 Schmidt JC, Sahrmann P, Weiger R, Schmidlin PR, Walter C (2013).

Biologic width dimensions- a systematic review. J Clin Periodontol 40(5): 493-504 Shobha KS, Mahantesha, Seshan H, Mani R, Kranti K (2010). Clinical evaluation of the biological width following surgical crown-lengthening procedure: A prospective study. J Ind Soc Periodontol 14(3): 160-167 Silness, J (1970). Periodontal conditions in patients treated with dental bridges. 3. The relationship between the location of the crown margin and the periodontal condition. J Periodontal Res 5: 225-229 Tal H, Soldinger M, Dreiangel A, Pitaru S (1989). Periodontal response to long-term abuse of the gingival attachment by supracrestal amalgam restorations. J Clinical Periodontol 16: 654–659 Vacek J, Gher M, Assad D, Charles Richardson A, Giambarresi L (1994). The dimension of the human dentogingival junction. Int J Periodontics Restorative Dent 14: 154-165

Reprinted with permission by Aesthetic Dentistry Today August 2016

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Simplifying composite placement in the interproximal zone Douglas Terry1 and Mark Stankewitz2

Introduction Understanding the importance of particle size and shape in the utilisation of new composite resin formulations with techniques to optimise the materials’ properties allows the clinician to attain predictable and pleasing aesthetic results.

In the past, when utilising composite resin material to achieve a restorative result with optimal physical and mechanical characteristics, it often required the use of a combination of hybrid and microfill. The hybrid provided the strength and sculptability and the microfill furnished the polish and durability of the restoration.

Layering techniques were developed for use with smaller increments of composite resin material to improve and optimise the depth of cure while reducing the effects of shrinkage and stress forces during the polymerisation process (Tjan, Glancy, 1988; Kovarik, Ergle, 1993). Yet, when different restorative composites of varying refractive indexes, shades and opacities were stratified, clinicians observed a ‘polychromatic effect’ (Dietschi, 1995). However, by utilising an anatomic stratification with successive layers of dentine, enamel and incisal composite, a more realistic depth of colour could be achieved, as well as surface and optical characteristics that mimic nature (Jefferies, 1998; Donly, Browning, 1992).

The improvements in the restorative quality and aesthetic result that have developed from the inequities of these different composite resin systems (hybrid and microfill), in conjunction with the use of innovative placement techniques to optimise the materials’ properties, have stimulated scientists, researchers, clinicians and manufacturers to explore and develop new nanoparticle formulations of restorative biomaterials.

Materials that are not only applied in relationship to the natural tissue anatomy, but that have physical, mechanical, and optical properties similar to that of tooth structure.

Nanotechnology

Douglas A. Terry, DDS Clinical Assistant Professor, Department of Restorative Dentistry and Biomaterials, University of Texas Health Science Center Dental Branch, Houston, Texas, USA. Private Practice, Houston, Texas, USA. E-mail: dterry@dentalinstitute.com or dterry@dentalinstitute.com

1

2

Mark L. Stankewitz DDS, CDT

Nanotechnology, or molecular manufacturing, may provide the crucial information for determining how to best utilise the composite materials (Kirk et al, 1991). By understanding how the actual size and shape of filler materials influences the mechanical and physical properties of the material, the potential for improved adhesion and the clinical success of the restoration is increased.

Composite resin with filler particle size that is dramatically smaller in size can be dissolved in higher concentrations and polymerised into the resin system with molecules that can be designed to be compatible when coupled with a polymer, and provide unique characteristics (physical, mechanical, and optical).

In addition, optimising the adhesion of restorative biomaterials to the mineralised hard tissues of the tooth is a decisive factor for enhancing the mechanical strength, marginal adaptation and seal, while improving the reliability and longevity of the adhesive restoration. Currently, the particle size of many of the conventional composites are so dissimilar to the structural sizes of the hydroxyapatite crystal, dental tubule and enamel rod, that there is a potential for compromises in adhesion between the

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macroscopic (40nm to 0.7um) restorative material and the nanoscopic (1 to 10 nanometers in size) tooth structure (Muselmann, 2003). However, nanotechnology has the potential to improve this continuity between the tooth structure and the nanosized filler particle and provide a more stable and natural interface between the mineralised hard tissues of the tooth and these advanced restorative biomaterials.

A nano-hybrid flowable composite resin system (G-aenial Universal Flo, GC America) may possess these improved physical, mechanical and optical properties. These properties and the clinical behaviour of this biomaterial formulation is contingent upon its structure. This resin filler technology allows a higher filler loading because of the fine filler size, uniform shape and distribution of particles. This resin filler chemistry allows the particles to be situated very closely to each other and the reduced interparticle spacing and homogeneous dispersion of the particles in the resin matrix increases the reinforcement and protects the matrix (Bayne, Taylor, Heymann, 1992; Turssi, Ferracane, Vogel, 2005; Lim et al, 2002).

In addition, the proprietary chemical treatment of the filler particles allows proper wettability of the filler surface by the monomer and thus an improved dispersion and a stable and stronger bond between the filler and resin. Research studies clearly indicate the significance that filler content and coupling agents represent in determining characteristics such as strength and wear resistance (Lim et al, 2002; Venhoven et al, 1996; Condon, Ferracane, 1997; Beatty et al, 1998). Recent studies report that flowable composites have

Figure 2a

Figure 2b

Figure 1

comparable shrinkage stress to conventional composites (Baroudi, Silikas, Watts, 2008; Cadenaro et al, 2009; Gallo et al, 2010).

According to the manufacturers, this next generation flowable resin formulation is purported to offer mechanical, physical and aesthetic properties similar or greater than many conventional hybrid composites (Yamase et al, 2010).

The clinical attributes of the material include improved adaptation to the internal cavity wall with easier insertion and manipulation, increased wear resistance and enhanced polishability and retention of polish. They also show greater elasticity and colour stability as well as a radiopacity similar to enamel.

Figure 2c

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Figure 3a

Figure 3b

Figure 4a

Figure 4b

Figure 5a

Figure 5b

Simplifying the application technique Adhesive procedures require properly integrating multiple interrelated steps during the restorative process, which increases the potential for error. Restorative complications and compromised clinical results can occur from improper placement of these adhesive materials. Although not scientifically proven, logic dictates that reducing the possibility of error by simplifying the application of materials should improve the restorative result and the quality of the restoration.

The following clinical presentation describes a simplified technique utilising a next generation nanoparticle flowable composite resin (G-aenial, GC America) to restore the interproximal zone.

Restoring the interproximal zone Restoring the interproximal zone with composite resin restorations using conventional hybrid composites has always presented challenges. Improper placement of these viscous composite materials can result in gaps, voids and deficient

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Figure 6a

Figure 6c

Figure 6b

marginal seal at the restorative interface. However, by utilising a modified self-etch technique and a simplified placement of a next generation flowable an ideal toothrestorative interface can be achieved.

The patient presents with interproximal caries on the mesial aspect of the mandibular left lateral incisor (Figure 1). After radiographic evaluation (Figure 2a), a shade comparison was performed prior to the restorative procedure (Figures 2b and 2c). The dehydration of the tooth from water molecules being depleted from the enamel rods can result in improper shade matching.

Once anaesthesia had been administered to the patient, the tooth was isolated with a dental dam to protect against contamination, using a modified technique. The technique involved the creation of an elongated hole that allowed placement of the dental dam over the retainers to achieve adequate field control and protect against contamination (Croll, 1985; Liebenberg, 1994). The caries was removed with a #2 high-speed round bur (#2 round bur, Brasseler USA), which produces rounded line angles (Figures 3a and 3b). The outline form was as conservative as possible without removing healthy tooth structure unless dictated by caries.

The axial line angles may vary in pulpal depth with the thickness of the enamel portion of the external walls and the

axial wall will be outwardly convex, following the normal external tooth contour and the DEJ, both inciso-gingivally and facio-lingually (Sturdevant, 2002).

To allow for a better resin adaptation, all internal line angles were rounded and cavity walls made smooth.

Sufficient retention for composite is achieved primarily by micromechanical adhesion to the surrounding enamel and underlying dentine and it is not necessary to produce an undercut in the preparation (Sturdevant, 2002). A circumferential bevel is placed in enamel using a tapered diamond bur (Figures 4a and 4b). An enamel bevel is indicated because it increases the surface area for end-on etching of the enamel rods for an increased etched surface, resulting in a stronger enamel to resin bond, which increases the retention of the restoration and reduces marginal leakage and discolouration (Sturdevant, 2002; Oilo, Jorgenson, 1977; Lorton, Brady, 1981). Also, placement of a cavosurface bevel improves the aesthetic integration of restorative material with the colours of the surrounding tooth structure (Sturdevant, 2002; Oilo, Jorgenson, 1977; Lorton, Brady, 1981; Sturdevant, 1995).

However, the cavosurface is not bevelled if little or no enamel is present or access is difficult for finishing procedures. A gingival bevel is not recommended if the

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preparation extends gingivally on to root structure or is of poor enamel quality. In addition, bevels are not placed on lingual surface margins that are in areas of centric contact or subjected to heavy occlusal forces, because composite has a lower wear resistance than enamel for withstanding heavy occlusal forces (Sturdevant, 2002). Thus, bevelling should be performed on class III preparations when there is adequate enamel present because it increases the potential for bonding, however it should not be placed on margins in the occlusal contact zone.

Bevelling increases the fracture resistance by increasing the bulk of the restoration, increases the bonding surface area, and decreases microleakage and marginal discolouration (Welk, Laswell, 1976) by exposing the enamel rods for etching (Lorton, Brady, 1981; Craig, 2001). The preparation was cleaned with a 2% chlorhexidine solution (Consepsis, Ultradent, South Jordan, UT), rinsed and lightly air-dried.

A dead metal matrix was placed and secured in the interproximal zone and a selective enamel etch procedure was performed. The prepared and unprepared enamel was etched with a 37.5% phosphoric acid gel (GEL Etchant, Kerr/Sybron, Orange, CA) for 15 seconds and rinsed for five seconds (Figures 5a and 5b). A self-etch adhesive (G-aenial Bond, GC America) was placed on the enamel and dentine surfaces with an applicator tip for 10 seconds, air-dried for five seconds using an A-dec warm air tooth dryer and light-cured for 10 seconds (Figures 6a, 6b, 6c). The dead metal matrix was replaced with a mylar plastic strip in the interproximal zone to confine and adapt the composite material to the tooth surface.

The mylar strip produces a smooth surface (Chung, 1994) while maintaining the anatomical contour during the polymerisation process (Figure 7).

A bleach shaded flowable composite material (G-eanial

Figure 8a

Figure 8b

Figure 8c

Figure 7

Universal Flo, GC America) was injected into the preparation and the syringe tip was slowly removed while extruding the material. The mylar strip was firmly adapted to an ideal contour and light cured for 40 seconds using a ramp mode (Figures 8a-8e).

The material is thixotrophic; this property allows the material to structurally breakdown so it flows through the syringe tip when the material is stressed, then the hydrogen bonding restructures and it becomes more viscous (Craig, 2001). Uno and Asmusen (1991) suggest that using a slower polymerisation causes an improved flow of molecules in the material while decreasing the polymerisation shrinkage stress in the restoration.

The mylar strip was removed and the interproximal region was inspected for any residual composite resin tags or overhangs. The excess residual resin was removed with a surgical blade (#12 BD Bard-Parker, BD Medical) (Figure 9).

The proximal surfaces were cleaned and smoothed with a loose abrasive diamond polishing paste, which was carried into the interproximal region with finishing strips (Figures 10a,

Figure 8d

Figure 8e

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Figure 10b

Figure 10a

Figure 9

Figure 10c

10b, 10c). The proximal surface was inspected for adequate contact with unwaxed floss prior to removing the dental dam (Figure 11).

After the dam was removed, a definitive lustre and surface reflectivity was accomplished with a goat-hair wheel and diamond polishing paste using an intermittent staccato motion (Figure 12). This restorative procedure demonstrates the optimal aesthetic results that can be achieved in the interproximal zone through proper adhesive protocol and a simplified application of flowable composite resin (Figure 13).

Figure 11

Conclusion The continual development of new technology changes and, hopefully, improves, the practice of dentistry. Understanding the importance of particle size and shape in the utilisation of new composite resin formulations with techniques to optimise the materialsâ&#x20AC;&#x2122; properties allows the clinician to attain predictable and pleasing aesthetic results. Although the longterm benefits of this material remain to be determined, the utilisation of an optimised nanoparticle flowable composite in the aforementioned patient demonstrated enhanced

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Figure 12

Figure 13

sculptability, the polishability of a microfill, the strength of a hybrid, and the ability to simulate the optical properties of the natural tooth. Through continued advancement in clinical and material research, refinements in formulations will continue to improve.

13. Condon JR, Ferracane JL. Factors effecting dental composite wear in vitro. J Biomed Mater Res 1997;38:303-13.

14. Beatty MW, Swartz ML, Moore BK, et al. Effect of microfiller fraction and silane treatment on resin composite properties. J Biomed Mater Res 1998;40:12-23.

15. Baroudi K, Silikas N, Watts DC. Edge -strength of flowable resin-composites. J Dent 2008; 36:63-8.

16. Cadenaro M, Marchesi G, Antoniolli F, et al. Flowability of composites is no guarantee for contraction stress reduction. Dent Mater 2009;25:649-54.

17. Gallo JR, Burgess JO, Ripps AH, et al. Three-year clinical evaluation of two flowable composites. Quintessence Int 2010;41:497-503.

18. Yamase M, Maseki T, Nitta T, et al. Mechanical properties of various latest resin composite restoratives. J Dent Res 89(Spec Iss A):abstract 464, 2010.

19. Croll TP. Alternative methods for use of the rubber dam. Quint Int 1985; 16:387-392.)

20. Liebenberg WH. General field isolation and the cementation of indirect restorations: Part 1. J Dent Assoc of South Afr 1994; 49(7): 349-353.

21. Sturdevant CM. Class III, IV and V Direct Composite and other tooth-colored restorations. 4th St. Louis, MI: Mosby, In: The art and science of operative dentistry, pp. 2002:490,491, 503-536.

22. Oilo G, Jorgenson KD. Effect of beveling on the occurrences of fractures in enamel surrounding composite resin fillings. J Oral Rehab 1977; 4: 305.

23. Lorton L, Brady J. Criteria for successful composite resin restorations. Gen Dent 1981; 29(3): 234-236.

24. Sturdevant CM Dental Materials ed. 3rd In: The art and science of operative dentistry. St. Louis, MI: Mosby, 1995: 262.

25. Welk DA, Laswell HR. Rationale for designing cavity preparations in light of current knowledge and technology. Dent Clin North AM 1976; 20(2): 231.

26. Craig RG. Restorative dental materials. ed 11. St. Louis, MI: Mosby, 2001.

27. Chung K. Effects of finishing and polishing procedures on the surface texture of resin composites. Dent Mater 1994; 10: 325-330.

28. Uno S, Asmussen E. Marginal adaptation of a restorative resin polymerized at reduced rate. Scand J Dent Res 1991;99(5): 440-445.

References 1. Tjan AH. Glancy JF. Effects of four lubricants used during incremental insertion of two types of visible light-activated composites.

JProsthet Dent 1988;60(2):189-194.

2. Kovarik RE, Ergle JW. Fracture toughness of posterior composite resins fabricated by incremental layering. J Prosthet Dent 1993;69(6):557-560.

3. Dietschi, D. Free-hand composite resin restorations: a key to anterior aesthetics. Pract Periodontics Aesthet Dent 1995;7(7):15-25.

4. Jefferies SR. The art and science of abrasive finishing and polishing in restorative dentistry. Dent Clin North Am 1998;32(4):613-627.

5. Donly, KJ and Browning, R, “Class IV preparation design for microfilled and macrofilled composite resin”, Pediatric Dentistry, January/February, 1992, 14:1; 34-36.

6. Kirk RE, Othmer DF, Kroschwitz J, Howe-Grant . Encyclopedia of Chemical technology. 4th ed. New York Wiley;1991:397.

7. Muselmann M. Composites make large difference in “small” medical, dental applications, Comp Tech; December 2003:24-27.

8. Bayne SC, Taylor DF, Heymann HO. Protection hypothesis for composite wear. Dent Mater 1992;8(5):305-9.

9. Turssi CP, Ferracane JL, Vogel K. Filler features and their effects on wear and degree of conversion of particulate dental resin composites. Biomater 2005;4932-7.

10. Lim BS, Ferracane JL, Condon JR, Adey JD. Effect of filler fraction and filler surface treatment on wear of microfilled composites. Dent Mater 2002;18:1-11.

11. Venhoven BMA, de Gee Aj, Werner A, et al. Influence of filler parameters on the mechanical coherence of dental restorative resin composites. Biomater 1996;17(7):735-40.

12. Condon JR, Ferracane JL. In vitro wear of composite with varied cure, filler level, and filler treatment. J Dent Res 1997;76:1405-11.

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Pulp revascularisation in a traumatised and necrotic tooth Ricardo Machado,1 Gustavo Almeida,2 Thâmara Silva Santos,3 Brunna Presmini Barbosa,4 Guilherme Augusto Moreira5 and Alberto Porto Junior6

Ricardo Machado is professor of multidisciplinary clinic I and II (endodontics) and supervised stage in multidisciplinary clinic I (endodontics) at the School of Dentistry, Paranaense University – UNIPAR, Francisco Beltrão, Paraná, Brazil.

1

Gustavo Almeida is professor of endodontics at the Brazilian Dental Association – ABO, Ilhéus, Bahia, Brazil.

2

Thâmara Silva Santos is specialist in endodontics at the Brazilian Dental Association – ABO, Ilhéus, Bahia, Brazil.

3

Brunna Presmini Barbosa is an undergraduate student at the School of Dentistry, Paranaense University – UNIPAR, Francisco Beltrão, Paraná, Brazil.

4

Guilherme Augusto Moreira is an undergraduate student at the School of Dentistry, Paranaense University – UNIPAR, Francisco Beltrão, Paraná, Brazil.

6 Alberto Porto Junior is professor of endodontics at the Brazilian Dental Association – ABO, Ilhéus, Bahia, Brazil.

5

The greatest difficulties in carrying out root canal treatments in teeth with pulp necrosis and incomplete root formation lie in the limited efficiency of transoperative cleaning and in the great possibility of overfilling. This is mainly due to the divergence in the root canal walls and lack of apical constriction (Thomson, Kahler, 2010; Forghani, Parisay, Maghsoudlou, 2013).

Successive changes of intracanal dressings using calcium hydroxide pastes are performed to reduce the difficulties imposed by treating teeth with pulp necrosis and incomplete root formation, by boosting disinfection and inducing apexification (Silveira et al, 2015). However, the major disadvantage of this therapeutic strategy is that the procedure implies a long treatment period; hence, there is a real possibility of fracture and reinfection (Cvek, 1992; Andreasen, Farik, Munksgaard, 2002; Rosemberg, Murray, Namerow, 2007; Hawkins, Torabinejad, Retamozo, 2015; Valera et al, 2015).

Mineral trioxide aggregate has been suggested as an alternative, to eliminate long treatment periods (Pradhan et al, 2006; Raju, Yadav, Kumar, 2014; Badole et al, 2015). However, both calcium hydroxide pastes and mineral trioxide aggregate are normally used only to induce apexification. Neither is able to effectively induce root formation and termination of dentine deposition on the side walls of the root canal (Valera et al, 2015; Pradhan et al, 2006; Raju, Yadav, Kumar, 2014; Badole et al, 2015; Bose, Nummikoski, Hargreaves, 2009). Consequently, there has been a steady search for new alternatives.

Pulp revascularisation is a process by which the root canals of necrotic teeth with incomplete root formation are mostly disinfected using copious irrigation with an antibacterial solution and application of a combination of antibiotics, such as ciprofloxacin, metronidazole, minocycline, and amoxicillin (Hoshino et al, 1996; Sato et al, 1996; Kahler et al, 2014), or calcium hydroxide pastes (Soares Ade et al, 2013; Nagata et al, 2014). In another visit, intracanal bleeding is stimulated to produce a blood clot to act as a matrix for the restoration of the vascular nerve bundle. Cervical sealing is then performed (Iwaya, Ikawa, Kubota, 2001; Banchs, Trope, 2004; Chueh, Huang, 2006; Lovelave et al, 2011).

This article presents a case where pulp revascularisation was opted for instead of inducing apexification, after a trauma in the upper right lateral incisor. The 12-month follow-up evidences the success of the treatment performed.

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Figure 1a: Initial radiograph.

Figure 1b: MTA used as cervical barrier and GIC used as a temporary restorative material.

Figure 1c: Five-month follow-up.

Figure 1d: One-year follow-up

Case report A 10-year-old male patient was seen at the Endodontics Specialization Course of the Brazilian Dental Association, Brazil, accompanied by his caregiver. The patient reported that he had suffered a dental injury in the anterior maxillary region about two years prior, but had only begun to feel pain, swelling and fistula in the region a few weeks before the visit. No relevant systemic diseases were reported. The clinical examination included palpation exams, tooth mobility analysis, cold thermal tests (Endo Ice, Hygenic, Akron) and periodontal probing in the incisors and canines of the region.

All of these examinations and tests were within normal limits, except for the upper right lateral incisor, which did not respond to thermal tests and showed grade II mobility.

Radiographic examination revealed the presence of apical periodontitis in the upper right lateral incisor, as well as incomplete root formation (Figure 1a). The diagnosis of chronic periapical abscess was made by associating the information obtained from the clinical and radiographic examinations.

In the first appointment, it was decided that only semi-rigid splinting would be performed to stabilise dental mobility.

Patient contact was lost, and the splinting was removed only two months later.

In the second appointment, endodontic access was performed after anaesthesia (2% lidocaine and epinephrine 1:80.000) and placement of the rubber dam, using 1016HL and 3083 drills (Dentsply Maillefer). Only one canal orifice was located. The working length was determined by means of an electronic foramen locator (Elements Apex Locator, Sybronendo) and instrumentation was performed according to the crown down technique, using K-files from the third series (Dentsply Maillefer). Irrigation was performed using 2% chlorhexidine gel and 2.5ml of saline solution (Fórmula & Ação) at each change of files.

Then, antibiotic paste consisting of ciprofloxacin (200mg) and metronidazole (500mg) was placed. A microhybrid composite resin (Z100, 3M Espe) was used as a temporary sealing material.

Twenty-nine days later, after anaesthesia (2% lidocaine and epinephrine 1:80.000) and placement of the rubber dam, the microhybrid composite resin used as a temporary sealing material and the antibiotic paste were removed with a 1016HL drill (Dentsply Maillefer) and profuse irrigation was performed with saline solution and 2% chlorhexidine gel (Fórmula & Ação), respectively. The canal was dried with paper points (Tanari) and bleeding was stimulated with a 30 k-file (Dentsply Maillefer), eventually stabilising the clot at 3mm below the cementoenamel junction. Mineral trioxide aggregate (Angelus) was used as cervical barrier. A glass ionomer cement (Ketac-Fil, 3M Espe) was used as a temporary restorative material (Figure 1b). The patient was then referred back to his clinician to perform the definitive restoration.

After a five-month follow-up, mobility and response to palpation and percussion tests were normal. Stabilisation of the periradicular disease was confirmed (Figure 1c), and the patient no longer showed any symptoms. However, the treated tooth still showed no sensitivity to thermal tests. After 12 months, a radiographic exam showed a considerable thickening of the root side walls, completion of the root formation and total healing of the periradicular disease. A considerable absorption of mineral trioxide aggregate was also observed, suggesting the occupation of root canal space by pulp tissue and dentine deposition (Figure 1d). The tooth responded normally to cold sensitivity tests, indicating the success of the treatment performed.

Discussion Until recently, apexification has been the only alternative to maintain teeth with pulp necrosis and incomplete root formation. However, the major drawback of this therapeutic strategy is that the procedure requires a long treatment period with successive changes of dressings of calcium hydroxide pastes; hence, there is a real possibility of fracture and reinfection (Cvek, 1992; Andreasen, Farik, Munksgaard, 2002; Rosemberg, Murray, Namerow, 2007; Hawkins, Toabinejad, Retamozo, 2015; Valera et al, 2015). For this

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reason, mineral trioxide aggregate was suggested as an alternative to eliminate long treatment periods (Pradhan et al, 2006; Raju, Yadav, Kumar, 2014; Badole et al, 2015).

However, neither treatment strategy is able to effectively induce radicular dentine formation and dentine deposition on the side walls of the root canal (Bose, Nummikoski, Hargreaves, 2009).

The main objectives of pulp revascularisation are to reestablish the vascular nerve bundle and complete the root formation process (Forghani, Parisay, Maghsoudlou, 2013; Saoud et al, 2014). Consequently, the respective clinical actions are considerably different from those of apexification.

In the present case, chlorhexidine was used as an auxiliary chemical solution, because of its lower toxicity, compared with sodium hypochlorite (Gomes-Filho et al, 2008), considering the real possibility of extravasation of the irrigation solutions during treatment, due to lack of apical constriction. Recently published research has also used similar protocols (Soares Ade et al, 2013; Nagata et al, 2014).

The use of calcium hydroxide (Soares Ade et al, 2013; Nagata et al, 2014) and/or antibiotic pastes (Hoshino et al, 1996; Sato et al, 1996; Kahler et al, 2014) for pulp revascularisation is critical in cases of necrotic teeth with incomplete root formation. These pastes are responsible for the disinfection process, considering that conventional cleaning and shaping cannot be performed, owing to the anatomic features of these teeth. However, previous studies have demonstrated the incidence of severe colour changes after using minocycline (Kahler et al, 2014). Therefore, ciprofloxacin and metronidazole were the medications of choice for the present case.

The absence of pain symptoms, the disappearance of possible fistula, the continuation of root development and the restoration of sensitivity to thermal change are the key success factors associated with pulp revascularisation (Kahler et al, 2014). All of these characteristics were confirmed in the case presented here, highlighted by complete root development after 12 months. Iwaya et al (2001) and Banchs and Trope (2004) reported clinical cases of pulp revascularisation, where complete apical closure occurred only after 30 and 24 months, respectively. Studies in different medical fields have shown that individuals can respond differently to similar interventions, and that these responses are strongly influenced by their systemic and immune conditions (Cooke et al, 2004; Kosalaraksa et al, 2011).

This could have been a crucial factor for the quicker

completion of the root formation in the case presented, in comparison with the cases mentioned above.

The case presented in this article confirms that pulp revascularisation is a viable alternative for the treatment of teeth with pulp necrosis and incomplete root formation.

However, considering the principles guiding evidence-based dentistry, more longitudinal clinical studies, especially of a prospective nature, are needed to prove its effectiveness.

Conclusions The purpose of this article was to report a pulp revascularisation success story in a tooth with pulp necrosis and incomplete root formation. This procedure appears to be a promising alternative to deal with this clinical situation.

However, more research is needed to prove its effectiveness.

References Andreasen JO, Farik B, Munksgaard EC (2002) Long-term calcium hydroxide as a root canal dressing may increase risk of root fracture. Dent Traumatol 18: 134-7 Badole GP, Warhadpande MM, Bahadure RN, Badole SG (2015) Nonsurgical endodontic treatment of permanent maxillary incisors with immature apex and a large periapical lesion: a case report. Gen Dent 63: 58-60 Banchs F, Trope M (2004) Revascularization of immature permanent teeth with apical periodontitis: new treatment protocol? J Endod 30: 196-200 Bose R, Nummikoski P, Hargreaves K (2009) A retrospective evaluation of radiographic outcomes in immature teeth with necrotic root canal systems treated with regenerative endodontic procedures. J Endod 35: 1343-9 Chueh LH, Huang GTJ (2006) Immature teeth with periradicular periodontitis or abscess undergoing apexogenesis: a paradigm shift. J Endod 32: 1205-8 Cooke A, Zaccone P, Raine T, Phillips JM, Dunne DW (2004) Infection and autoimmunity: are we winning the war, only to lose the peace? Trends Parasitol 20: 316-21 Cvek M (1992) Prognosis of luxated non-vital maxillary incisors treated with calcium hydroxide and filled with guttapercha: a retrospective clinical study. Endod Dent Traumat 8: 45-55 Forghani M, Parisay I, Maghsoudlou A (2013) Apexogenesis and revascularization treatment procedures for two traumatized immature permanent maxillary incisors: a case report. Restor Dent Endod 38: 178-91 Gomes-Filho JE, Aurélio KJ, Costa MM, Bernabé PF (2008) Comparison of the biocompatibility of different root canal

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irrigants. J Appl Oral Sci 16: 137-44 Hawkins JJ, Torabinejad M, Retamozo B (2015) Effect of three calcium hydroxide formulations on fracture resistance of dentin over time. Dent Traumatol 31: 380-4 Hoshino E, Kurihara-Ando N, Sato I, Uematsu H, Sato M, Kota K, Iwaku M (1996) In-vitro antibacterial susceptibility of bacteria taken from infected root dentine to a mixture of ciprofloxacin, metronidazole and minocycline. Int Endod J 29: 125-30 Iwaya SI, Ikawa M, Kubota M (2001) Revascularization of an immature permanent tooth with apical periodontitis and sinus tract. Dent Traumatol 17: 185-7 Kahler B, Mistry S, Moule A, Ringsmuth AK, Case P, Thomson A, Holcombe T (2014) Revascularization outcomes: a prospective analysis of 16 consecutive cases. J Endod 40: 333-8 Kosalaraksa P, Srirompotong U, Newman RW, Lumbiganon P, Wood JM (2011) Serological response to trivalent inctive influenza vaccine in HIV-infected children with different immunologic status. Vaccine 29: 3055-60 Lovelace TW, Henry MA, Hargreaves KM, Diogenes A (2011) Evaluation of the delivery of mesenchymal stem cells into the root canal space of necrotic immature teeth after clinical regenerative endodontic procedure. J Endod 37: 133-8 Nagata JY, Gomes BP, Rocha Lima TF, Murakami LS, de Faria DE, Campos GR, de Souza-Filho FJ, Soares Ade J (2014) Traumatized immature teeth treated with 2 protocols of pulp revascularization. J Endod 40: 606-12 Pradhan DP, Chawla HS, Gauba K, Goyal A (2006) Comparative evaluation of endodontic management of teeth with unformed apices with mineral trioxide aggregate and calcium hydroxide. J Dent Child 73: 79-85 Raju SM, Yadav SS, Kumar SRM (2014) Revascularization of

immature mandibular premolar with pulpal necrosis - a case report. J Clin Diagn Res 8: 29-31 Rosemberg B, Murray PE, Namerow K (2007) The effect of calcium hydroxide root filling on dentin fracture strength. Dent Traumatol 23: 26-9 Saoud TM, Zaazou A, Nabil A, Moussa S, Lin LM, Gibbs JL (2014) Clinical and radiographic outcomes of traumatized immature permanet necrotic teeth after revascularization/revitalization therapy.

J Endod 40: 1946–52 Sato I, Ando-Kurihara N, Kota K, Iwaku M, Hoshino E (1996) Sterilization of infected root-canal dentine by topical application of a mixture of ciprofloxacin, metronidazole and minocycline in situ. Int Endod J 29: 118-24 Silveira CM, Sebrão CC, Vilanova LS, Sánchez-Ayala A (2015) Apexification of an immature permanent incisor with the use of calcium hydroxide: 16-year follow-up of a case. Case Rep Dent 1-6 Soares Ade J, Lins FF, Nagata JY, Gomes BP, Zaia AA, Ferraz CC, de Almeida JF, de Souza–Filho FJ (2013) Pulp revascularization after root canal decontamination with calcium hydroxide and 2% chlorexidine gel. J Endod 39: 417-20 Thomson A, Kahler B (2010) Regenerative endodonticsbiologically-based treatment for immature permanent teeth: a case report and review of the literature. Aust Dent J 55: 446-52 Valera MC, Albuquerque MT, Yamasaki MC, Vassallo FN, da Silva DA, Nagata JY (2015) Fracture resistance of weakened bovine teeth after long-term use of calcium hydroxide.

Dent Traumatol 31: 385-9

Reprinted with permission by ENDODONTIC PRACTICE December 2016

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Making sense of mouth ulceration: Skin disorders Crispian Scully1

The clinical appearance of an oral ulcer on its own is rarely diagnostic. In the light of multiple causes, some systematic way of dealing with ulceration is needed, such as my system of splitting causes into: • Systemic • Malignancy • Local • Aphthae • Drugs.

This article discusses the last of the systemic causes – skin disorders.

Skin disorders • • • • • •

Pemphigus Pemphigoid Dermatitis herpetiformis Linear IgA disease Epidermolysis bullosa Erythema multiforme.

Vesiculobullous diseases Vesiculobullous diseases are potentially life changing; for example, pemphigus is life threatening. Any ulceration, especially multiple, lasting more than three weeks must therefore be regarded with suspicion.

This article covers the more important vesiculobullous diseases, which are characterised by the formation of blisters (vesicles/bullae) within (intraepithelial) or beneath (subepithelial) the epithelium.

1

Professor Crispian Scully CBE FMedSci DSc FDS MD is professor emeritus at UCL, London, King James IV professor at the Royal College of Surgeons, Edinburgh, Harley Street Diagnostic Centre, 16 Devonshire Street and 19 Wimpole Street, London.

Pemphigus Pemphigus is the term for a group of rare autoimmune disorders; with antibodies directed mainly against epithelial intercellular ‘cement’ that helps keratinocytes adhere to each other (in desmosomes and termed desmoglein [DSG]).

Seen mainly in middle-aged and older people, and with a female predisposition, the common variant – pemphigus vulgaris (PV) – has a strong genetic background, and is prevalent in Ashkenazi Jews, Asians (India, Malays, Chinese, Japanese) and Mediterranean peoples.

HLA-DRB1*0402 or HLA-DQB1*0503 are found in more than 95% of PV patients.

Pemphigus is usually idiopathic but sometimes implicated are: • Pesticides (organophosphates) • Malignancy • Pharmaceuticals • Hormones • Infections/immunisations • Gastronomy • UV light • Stress.

Triggers occasionally include: • Drugs (thiols, phenols or non-thiol, non-phenols) • Foods (black pepper, garlic, leek, onion, pepper, red chilli, red wine, tea) • Radiation • Surgery.

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CLINICAL

• Autoantibody removal – Immunoadsorption – Plasmapheresis.

Oral lesions may be helped also by use of: • Topical corticosteroids (fluocinolone acetonide or clobetasol) • Intralesional steroids • Topical tacrolimus.

Figure 1: Pemphigus

Activation of HLA class II restricted, desmoglein-specific CD4 T effector lymphocytes drives autoreactive B-cell activity and autoantibody production and the ST18 gene regulates apoptosis and inflammation.

Pemphigus affects stratified squamous epithelia of skin and malpighian mucous membranes.

Pemphigus vulgaris manifests with skin blistering and mucosal lesions and, if left untreated, has a high mortality.

Oral lesions are invariable and seen early. They include blisters that rupture to erosions as well as persistent ulcers.

Lesions are seen mainly where there is trauma and Nikolsky’s sign is positive – pressure on the blister causes it to spread. Irregular red erosions seen early on have a whitish surround due to necrotic epithelium (Figure 1) but there is a fibrinous slough on older erosions.

People with PV have an increased incidence of other autoimmune disorders themselves (especially myasthenia gravis, Basedow disease, rheumatoid arthritis, systemic lupus erythematosus) and in their blood relatives (type 1 diabetes, autoimmune thyroid disease, less commonly PV).

Diagnosis is confirmed by histopathology, mainly. Biopsy is essential and shows acantholysis. Immunostaining by direct immunofluorescence (DIF) microscopy shows a net-like appearance of deposited IgG and C3. Indirect immunofluorescence (IIF) microscopy shows pemphigus antibodies.

Depending upon involvement of eyes, larynx, skin, and genitalia, appropriate referral to physicians is essential.

Management is by using: • Systemic immunosuppression • Corticosteroids • Alternates – Azathioprine – Dapsone – Intravenous immunoglobulins – Rituximab

Pemphigus variants Paraneoplastic pemphigus is the most important other pemphigus variant, seen usually in the sixth decade.

Associated with anti-plakin (plectin, desmoplakin I, desmoplakin II, bullous pemphigoid antigen I, envoplakin, and periplakin) antibodies plus DSG-1 and DSG-3, it often causes oral ulceration on the lips and tongue, along with palmar/plantar bullous lesions.

The prognosis is poor with a mortality of approximately 90% because of the presence of lymphoproliferative disorders such as: • Non-Hodgkin’s lymphoma • Castleman’s disease • Chronic lymphoid leukaemia • Adenocarcinomas, Kaposi and other sarcomas • Bronchiolitis obliterans.

Immune-mediated subepithelial bullous diseases Immune-mediated subepithelial bullous diseases (IMSEBD) is a group of blistering diseases, less dangerous than PV, in which autoantibodies to various components of the hemidesmosomes that link keratinocytes to the epithelial basement membrane zone (EBMZ) cause subepithelial vesiculation and blistering of squamous epithelia.

Often in the past these IMSEBD have all been called pemphigoid but it is now recognised that other disorders can cause a similar clinical picture. Even pemphigoid has several variants.

Pemphigoid Pemphigoid is an autoimmune disorder that affects skin and/or mucosae associated with HLA-DQB1*0301. It may affect one or several sites, and oral lesions predominate in mucous membrane pemphigoid (MMP) subtypes.

MMP is uncommon, with a female predisposition and seen in the fifth to sixth decade of life. Rarely, it is drug-induced.

MMP affects mainly oral, ocular, nasal, nasopharyngeal, anogenital, laryngeal, and oesophageal mucosae. Sub-sets of patients with MMP have autoantibodies targeting antigens of the EBMZ, such as epiligrin and integrins. These may differ, depending on sites mainly involved: • Oral MMP: α-6 integrin

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S C U L LY

Figure 2: Pemphigoid causing desquamative gingivitis

• Ocular MMP: β-4 integrin.

MMP with oral lesions affects mainly the gingiva, soft and hard palate as well as buccal mucosae.

MMP is a common cause of: • Desquamative gingivitis – erythematous, ulcerated, tender gingiva, patchy distribution (Figure 2) • Erosions, arising from vesicles that burst within several days, causing persistent ulcers or erosions covered with yellowish slough and surrounding erythema (Figure 3).

Blood-filled blisters are sometimes seen.

Diagnosis is from a positive Nikolsky sign (ie, pressure on a blister causes it to spread). However, this is non-specific, therefore the following are also necessary: • Biopsy – oral (not ocular) mucosal biopsy • Immunostaining; shows linearly deposited IgG, IgA, or C3 at EBMZ. Management may be with: • Topical corticosteroids (fluocinolone acetonide or clobetasol) • Intralesional steroids • Topical tacrolimus • Systemic immunosuppressants in advanced cases (corticosteroid or alternates – azathioprine, dapsone, high dose IV Ig, rituximab).

Appropriate referral to physicians (depending upon involvement of eyes, larynx, skin, and genitalia), and need for systemic immunosuppression (severe or widespread disease) may be necessary.

Patients with apparently exclusive oral involvement may later develop ocular lesions. There is a higher relative cancer risk in MMP patients with autoantibodies to epiligrin/laminin-332 but a lower than expected relative cancer risk in patients with: • Exclusive oral mucosal disease (autoantibodies to α-6 integrin) • Exclusive ocular mucosal disease (autoantibodies to β4 integrin).

Figure 3: Erosions in pemphigoid

Dermatitis herpetiformis Dermatitis herpetiformis is an IMSEBD in which autoantibodies against epithelial transglutaminase cause an itchy rash on extensor surfaces, along with gluten sensitive enteropathy and oral blisters or desquamative gingivitis. Lesional biopsy on direct immunofluorescence shows granular deposits of IgA at basement membrane zone (BMZ).

Linear IgA disease Linear IgA disease (LAD) or chronic bullous disease of childhood is an IMSEBD similar to dermatitis herpetiformis but antibodies are against ladinin in the EBMZ, with linear IgA deposition.

References Gandolfo S, Scully C, Carrozzo M (2006) Oral medicine.

Elsevier Churchill Livingstone (Edinburgh and London). ISBN 13: 29780443100376 Scully C, Almeida ODP, Bagan J, Diz PD, Mosqueda A (2010) Oral medicine and pathology at a glance. WileyBlackwell (Oxford) ISBN 978-1-4051-9985-8 Scully C, Flint S, Bagan JV, Porter SR, Moos K (2010) Oral and maxillofacial diseases. Informa Healthcare (London and New York). ISBN-13: 9780415414944 Scully C, Bagan JV, Carrozzo M, Flaitz C, Gandolfo S (2012) Pocketbook of oral disease. Elsevier, London. ISBN 978-0-70204649-0 Scully C (2013) Oral and maxillofacial medicine. 3rd edition.

Churchill Livingstone (Edinburgh). ISBN 9780702049484 Scully C (2012) Aide memoires in oral diagnosis: mnemonics and acronyms (the Scully system). Journal of Investigative and Clinical Dentistry 3(4): 262-3 Scully C (2013) RULE for cancer diagnosis. British Dental Journal 215: 265-6

Reprinted with permission by Private Dentistry July 2014

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All products available from: HENRY SCHEIN HALAS • Tel: 1300 65 88 22 • www.henryschein.com.au 62 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION VOL. 12, NO. 1

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All products available from: HENRY SCHEIN HALAS • Tel: 1300 65 88 22 • www.henryschein.com.au 64 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION VOL. 12, NO. 1

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