International Dentistry Australasian Edition - Vol.11 No.4

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VOL. 1 1 NO. 4 IN THIS ISSUE

Fardad Shakibaie and Laurence J. Walsh Violet and blue light-induced green fluorescence emissions from dental calculus: a new approach to dental diagnosis Muhammad A. Bobat and Ephraim R. Rikhotso Clinical significance of the anterior loop of the mental nerve: anatomical dissection of a cadaver population Neil Gerrard Direct restoration in the aesthetic zone a case study Crispian Scully Making sense of mouth ulceration: Ulceration of local cause John Rhodes Non-surgical retreatment of a central incisor following dental trauma Yu-Yao Teoh, Basil Athanassiadis and Laurence J. Walsh The influence of aqueous and PEG 400 solvent vehicles on hydroxyl ion release from calcium hydroxide medicaments Crispian Scully Making sense of mouth ulceration: Drug-induced ulceration

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Contents Volume 11 No. 4

6 16

Clinical Violet and blue light-induced green fluorescence emissions from dental calculus: a new approach to dental diagnosis Fardad Shakibaie and Laurence J. Walsh

16

Case Report Clinical significance of the anterior loop of the mental nerve: anatomical dissection of a cadaver population Muhammad A. Bobat and Ephraim R. Rikhotso

24 Clinical

Direct restoration in the aesthetic zone - a case study Neil Gerrard

24

32 Clinical

Making sense of mouth ulceration: Ulceration of local cause Crispian Scully

36 Clinical Non-surgical retreatment of a central incisor following dental trauma John Rhodes

44

Clinical The influence of aqueous and PEG 400 solvent vehicles on hydroxyl ion release from calcium hydroxide medicaments Yu-Yao Teoh, Basil Athanassiadis and Laurence J. Walsh

58 Clinical

Making sense of mouth ulceration: Drug-induced ulceration Crispian Scully

62 Products

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Artwork sold supports Henry Schein Cares Foundation Henry Schein Halas, through the Henry Schein Cares Foundation, is always looking for ways to better serve underprivileged communities so that we can live our motto ‘doing well by doing good’. While our passion lies in oral health, where we often focus, sometimes other projects and outreaches demand our attention. Most recently, through our sister company in South Africa, we were given the opportunity to purchase a selection of African artwork. The quality of the pieces were outstanding and the underrepresented talent is undeniable.

The purchase greatly improved conditions for the artists and their communities but we were then left wondering, “What do we do with all these fantastic pieces?”

We decided to take a different approach during the 9th International Quintessence Symposium 2016 held in Sydney in October. Within the exhibition area we held our first ever Henry Schein Cares art exhibition.

Delegates were able to enjoy the artwork during their breaks and given the option to purchase them for extremely reasonable prices. All proceeds are going back into the Henry Schein Cares budget so that we can continue to support causes like this one. With more than half the paintings on display sold we will continue to showcase the African artwork wherever we have the opportunity.

There are still a great number of canvases we were not able to show and we look forward to showcasing them at future events. If you would like more information on the Henry Schein Cares Foundation or the artwork please visit www.henryschein.com.au or email scheincares@henryschein.com.au

Vol. 11 No. 4 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 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.

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CLINICAL

Violet and blue light-induced green fluorescence emissions from dental calculus: a new approach to dental diagnosis Fardad Shakibaie1 and Laurence J. Walsh1

Abstract Background: The purpose of this laboratory study was to explore the use of green fluorescence emissions elicited by violet and visible blue LED light excitation to assist in diagnosis of dental hard tissues, particularly to differentiate dental calculus from healthy tooth structure and dental caries. Methods: Microscopic digital photography of 100 teeth was undertaken using violet and blue LED illumination (405 and 455 nm wavelengths) using a custom-made stack of green compensating filters which removed the excitation light and imaged green fluorescence scores. Differences in green channel pixel values were analyzed using ANOVA. Results: Supra- and subgingival calculus showed moderately intense green fluorescence emissions. These emissions were stronger than dental caries (P<0.026), but less intense than those from sound tooth surfaces (P<0.0022). The presence of saliva on the surface did not significantly alter green fluorescence, while the presence of blood diluted in saliva depressed green fluorescence (P<0.015).

Conclusions: Using violet or blue illumination in combination with green compensating filters may have potential application for dental hard tissue diagnosis, particularly for differentiating dental calculus from sound tooth structure and from carious lesions.

Keywords: Dental Calculus, Detection, Fluorescence, Optical Imaging, Green Luminosity

Introduction

School of Dentistry, The University of Queensland, Brisbane, Australia

1

Corresponding author: Prof LJ Walsh School of Dentistry The University of Queensland UQ Oral Health Centre 288 Herston Road, Herston QLD 4006 Australia Email: l.walsh@uq.edu.au Tel. + 61 7 33658160 Fax. + 61 7 336 58199

Deposits of dental calculus when present either above the gingival margin or within periodontal pockets retain pathogenic microorganisms and their products, and have been linked to gingivitis and periodontitis.1,2 To ensure that clinicians are able to reliably detect calculus deposits, a range of special devices have been developed to augment traditional examination methods which rely on visual inspection for supragingival calculus, and tactile examination with a periodontal probe for subgingival calculus.

Such methods include fluorescence in the near infrared region elicited by incident visible red light.3-6 Their application includes both assessment of deposits present at baseline before debridement, and checking root surfaces for remaining deposits at the end of a debridement visit.7-10 The use of near infrared fluorescence emissions (such as in the DiagnoDENT) requires phototransistors and other electronic sensors to be used, 11,12 since these wavelengths fall outside the visible spectrum. An enhanced clinical method for calculus detection using visible light would, in contrast, rely on what fluorescence emissions the clinician could see themselves.

Subgingival calculus present on root surfaces associated with deep periodontal pockets can be seen with direct vision is when a surgical flap is raised.13 Another less invasive situation is when an intra-oral endoscopic camera is used for direct high magnification inspection of the subgingival environment. Such endoscopes (such as the Perioscope*) are shaped like periodontal probes or dental explorers, and contain solid glass rods or fiber-optic bundles within them, to both illuminate the object and then

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CLINICAL

transmit and magnify reflected images back to a sensor, to generate a video signal.13-15 There are already in clinical use a range of intra-oral cameras which employ fluorescence imaging to enhance detection of dental caries, with the excitation light being in the violet or blue range (400-470 nm wavelength), including the GC G-Cam=, Morita Penvieweri, and DÜrr VistaCamu.

These devices use orange or red filters to improve the signal to noise ratio for red fluorescence emissions from lesions of dental caries, for positive fluorescence imaging.6,16,17 The same devices could, however, also be used to view and capture images of supragingival calculus on tooth surfaces.

In a previous study, we showed that green fluorescence emissions are strong from normal tooth structure, but are reduced when dental caries is present, allowing lesions of dental caries to be differentiated from healthy tooth surfaces.18 Following on from this previous work, the present study was designed to explore whether green fluorescence emissions could also differentiate between dental calculus and sound tooth structure as well as dental caries, using the negative fluorescence approach with violet or blue light as the excitation source.

Materials and Methods Sample Preparation A total of 100 extracted human permanent teeth were selected from a large repository of extracted teeth collected from adults aged 18 years or more with the approval of the institutional ethics committee (Reference No: 2003000040) from a dental school exodontia clinic. A power analysis was undertaken to determine sample sizes in the various groups, based on data from a pilot study. The power analysis assumed α=0.05 and estimated β=0.2 (study power = 80%), giving N=20 per group for the three experimental groups: dental caries (group A), subgingival calculus (group B), and supragingival calculus (group C). There were a further 20 control samples included for both sound enamel (group D) and sound roots (group E), both which had been included in the previous study.18 All teeth had been gamma sterilized and were stored in a solution of 0.1% thymol in distilled water to maintain hydration. All samples in group A had coronal cavities extending at least mid-way into the dentine, whilst samples in groups B and C had calculus

*Dental View, Lake Forrest, California, USA = G-Cam ™, GC Corporation, Tokyo, Japan i Morita Penviewer™, J. Morita Manufacturing Corporation, Kyoto, Japan u VistaCam™ , DÜrr Dental GmbH, Bietigheim-Bissingen, Germany

deposits of between 5 and 20 mm2 in area which were then used for analysis. To ensure they remained fully hydrated, teeth were removed from their storage media and placed on blotting paper to remove excess fluid from the surface.

Imaging was completed within 10 minutes, so that dehydration did not occur.

Optical configuration The arrangement for light sources and imaging was identical to the previous investigation.18 In brief, two different excitation light sources were used, both of which were held at fixed positions 5 cm from the samples. The excitation LED light sources were as follows: for violet, the G-Light** (peak emission 405 nm, spectral range 390-420 nm), and for blue, the Tristar MR16== (peak emission 455 nm, spectral range 430-490 nm). Samples were viewed through a custom filter stack to remove the excitation light but allow green fluorescence to pass,18 and imaged first in the moist state with the surface free of excess fluid. To evaluate the impact of saliva and blood, samples were then imaged when covered by either a 7 μL or 14 μL drop of saliva (depending on the area to be covered), and finally when covered by anticoagulated blood. The saliva and blood were left on the surface for 3 minutes before imaging was undertaken. Both the saliva and blood were collected from a single healthy male volunteer. Their collection was approved by the institutional ethics committee (Reference No: 2006000701). The blood sample was collected in a heparinized tube and diluted into saliva to mimic the common clinical situation of gingival bleeding where blood becomes mixed into saliva. The ratio of the blood to saliva mix used was in the range of 0.57-0.71, which was the same as used in the previous study.6 For recording images of green fluorescence, a 3.3 megapixel digital cameraii was fitted to a stereoscopic microscopeuu. All images were taken in a dark room, using consistent low level ambient lighting and consistent exposure times for image series made using the same light source. The sample area imaged was 20 mm2. A custom-made stack of four circular green gelatin filters (two CC40G and two CC50G colour compensating Wratten filters)*** was prepared, as described previously.18 The stack of filters was **G-Light, GC America, Chicago, USA == Hi-Line Lighting Ltd, Kingston Upon Thames, UK ii Coolpix 995, Nikon, Tokyo, Japan uu U-PMTVC, Olympus, Tokyo, Japan ***Kodak, Tokyo, Japan

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Figure: 1. Typical patterns of strong green fluorescence under 405 nm violet light excitation from sound tooth structure. Supragingival calculus (1), subgingival calculus (2) and dental caries (3) can all be distinguished because of their darker appearance. Lesions of caries include cavitations (panels A and C), white spot lesions (panel B) and both together (panel E).

attached to the objective lens of the microscope as a long pass filter, to attenuate ultraviolet and blue excitation wavelengths, but allow green fluorescence emissions to pass.

Data Analysis From the digital images, the magnetic lasso tool in Adobe Photoshop CS2™ software was used to outline the sample target area, and the green channel data were computed using the histogram applet. As green channel data range from a minimum of zero (pure black) through to 255 (pure white), samples with greater green fluorescence show higher channel numbers. GraphPad Prism™ version 6 statistical software=== was used to compare green channel data from ===

GraphPad Software, La Jolla, California, USA

different sample types, under different conditions (free of fluid, saliva coated or blood coated). As data sets followed Gaussian distributions, ANOVA was used to analyze differences between groups, and repeated measures twoway ANOVA was used to compare samples under different surface conditions. The significance level was set as α=0.05.

Results In the images, the lower luminosity of supragingival calculus, subgingival calculus and dental caries (both white spot lesions and cavitations) could readily be distinguished from adjacent normal tooth structure which showed strong green fluorescence (Fig. 1 A-F).

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Figure 2: Boxplots showing green fluorescence elicited by violet light excitation (405 nm) under different surface conditions. The middle dot indicates the group mean, whereas the box plot itself indicates from top to bottom the maximum, 75% quartile, median, 25% quartile and minimum. Data for sound enamel and sound roots are taken from Ref. 18.

The boxplots for green fluorescence emitted from samples under violet or blue light excitation are shown in Figures 2 and 3, respectively, while Table 1 presents statistical comparisons of sample types.

Considered as a group, calculus samples in the moist state or when covered by saliva consistently gave luminosity scores up to 170 for violet light excitation, and up to 200 for blue light excitation. The differences between supragingival calculus and sound enamel and between sound roots and subgingival calculus, were both statistically significant (P<0.0023 and P<0.0001, respectively).

Regardless of whether surfaces were free of fluid or were coated with fluids, both types of calculus gave significantly stronger green fluorescence emissions than dental caries when excited by either violet or blue light (P<0.026). In contrast, there were no significant differences between supraand subgingival calculus under violet light (P=0.7001) or blue light (P=0.2125).

In terms of the effect of surface conditions under violet or blue light excitation (Table 2), there were no statistically significant differences between moist or saliva-coated surfaces for any sample type (P>0.05). In contrast, the presence of blood diluted into saliva significantly depressed

the green channel fluorescence emissions for all samples, compared to the same materials in a moist state (P<0.003) or when coated with saliva (P<0.015).

Discussion In a previous investigation, the potential usefulness of green fluorescence emissions for aiding in caries detection was shown, applying the principle of negative fluorescence where the target of interest appears dark against the surrounding healthy tissue.18 In this previous study, a custommade green filter stack was assembled to serve as a long pass filter, blocking reflections from the violet or blue light sources but allowing green fluorescence emissions to pass through to the camera. Using the same optical configuration, the present experiments extend the findings by exploring variations in green fluorescence between dental calculus and sound tooth structure, and between dental calculus and dental caries. While the strong green fluorescence emissions from sound tooth structure and corresponding lack of these from lesions of dental caries is a phenomenon that has been well described in the literature,18-20 the differences between dental calculus and dental caries have not hitherto been reported.

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Table 1. P values for differences between dental caries and calculus samples Sample Comparison

Violet Lighting

Blue Lighting

Caries vs Supragingival Calculus

0.0003

<0.0001

Caries vs Subgingival Calculus

0.0107

0.0004

Supra- vs Subgingival Calculus

0.4042

In terms of overall rankings, the results from the present study show the strongest emissions from sound tooth structure (200â&#x20AC;&#x201C;250 in luminosity), followed by dental calculus deposits (170-200), and then by dental caries (100-140).

While the numerical values shift according to whether violet or blue light is being used (being higher for blue than for violet), the ranking remains the same nonetheless. The use of intense 455 nm LED or diode laser light could therefore have application for differentiation between calculus deposits and other surfaces. Such an approach could be used in endoscopy of periodontal pockets deposits, 15 where the instrument is used within narrow and confined periodontal pockets.14,21 Finally, the present study is informative with regards to the potential influence of ambient fluids which may cover the tooth surface. In line with previous reports,16-18 there was no difference between moist surfaces and those coated with saliva. This is to be expected since water has very poor absorption of visible green, blue and violet light. As an extrapolation, one would not expect gingival crevicular fluid to absorb any of these same colours of

0.1384

light. There was, in contrast, a significantly reduced luminosity when blood was present, which can be explained by the strong absorption of all three colours of light into haemoglobin. The practical application of this finding is that for a device such as a periodontal endoscope, water irrigation could be used to remove blood from a periodontal pocket without impairing the green fluorescence readings.

Conclusion As a proof of concept study, this laboratory investigation shows that applying violet or blue light can elicit green fluorescence from healthy tooth structure, and that such emissions are reduced significantly where dental calculus is present, regardless of whether this is supragingival or subgingival calculus. The reduced green fluorescence is even greater for dental caries. Such an approach may have clinical utility to augment existing diagnostic methods, especially when blood on the surface is removed immediately prior to imaging.

Table 2. Differences due to surface conditions (dry versus saliva versus blood) Sample

DRY vs SALIVA

DRY vs BLOOD

SALIVA vs BLOOD

Dental Caries

0.4043

<0.0001

<0.0001

Supragingival Calculus

0.7846

<0.0001

<0.0001

Subgingival Calculus

0.0620

<0.0001

<0.0001

Dental Caries

0.7920

0.0001

<0.0001

Supragingival Calculus

0.0742

0.0028

0.0143

Subgingival Calculus

0.6093

<0.0001

0.0003

VIOLET LIGHT

BLUE LIGHT

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Figure 3: Boxplots showing green fluorescence elicited by blue light excitation (455 nm) under different surface conditions. Data for sound enamel and sound roots are taken from Ref. 18.

Conflict of interest The authors declare that they have no conflict of interests.

References 1. Shakibaie F, Gemmell E, Bird PS. A mouse model to study pathogenicity of Bacteroides forsythus. Periodontol 2001;22:5-8.

2. Bird PS, Shakibaie F, Gemmell E, Polak B, Seymour GJ. Immune response to Bacteroides forsythus in a murine model.

Oral Microbiol Immunol 2001;16:311-315.

3. Shakibaie F, Walsh LJ. Differential reflectometry versus tactile sense detection of subgingival calculus in dentistry. J Biomed Opt 2012;17:106017.

4. Shakibaie F, Walsh LJ. Surface area and volume determination of subgingival calculus using laser fluorescence. Lasers Med Sci 2014;29:519â&#x20AC;&#x201C;524.

5. Shakibaie F, Walsh LJ. Performance differences in the detection of subgingival calculus by laser fluorescence devices. Lasers Med Sci 2015;30:2281-2286.

6. Walsh LJ, Shakibaie F. Ultraviolet-induced fluorescence: shedding new light on dental biofilms and dental caries.

Australas Dent Pract 2007;18:56-60.

7. Krause F, Braun A, Frentzen M. The possibility of

detecting subgingival calculus by laser-fluorescence in vitro.

Lasers Med Sci 2003;18:32-35.

8. Shakibaie F, George R, Walsh LJ. Applications of laser induced fluorescence in dentistry. Int J Dent Clin 2011;3:26-29.

9. Folwaczny M, Heym R, Mehl A, Hickel R. The effectiveness of InGaAsP diode laser radiation to detect subgingival calculus as compared to an explorer. J Periodontol 2004;75:744-749.

10. Shakibaie F, Walsh LJ. DIAGNOdent Pen versus tactile sense for detection of subgingival calculus: an in vitro study.

Clin Exp Dent Res 2015;1:26-31.

11. Folwaczny M, Heym R, Mehl A, Hickel R. Subgingival calculus detection with fluorescence induced by 655 nm InGaAsP diode laser radiation. J Periodontol 2002;73:597601.

12. Shakibaie F, Walsh LJ. Laser fluorescence detection of subgingival calculus using the DIAGNOdent Classic versus periodontal probing. Lasers Med Sci 2016; DOI 10.1007/s10103-016-2027-3 [in-press] 13. Scheyer ET. Periodontal endoscopy in clinical practice. Pract Proced Aesthet Dent 2003;15(1):36-39.

14. Stambaugh RV, Myers G, Ebling W, Beckman B,

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Stambaugh K. Endoscopic visualization of the submarginal gingiva dental sulcus and tooth root surfaces. J Periodontol 2002;73:374-382.

15. Stambaugh RV. A clinician's 3-year experience with perioscopy. Compend Contin Educ Dent 2002;23:10611070.

16. Shakibaie F, Walsh LJ. Effect of oral fluids on dental caries detection by the VistaCam. Clin Exp Dent Res 2015;1:74-79.

17. Shakibaie F, Walsh LJ. Dental calculus detection using the VistaCam. Clin Exp Dent Res 2016;[in-press, accepted 5th Jul 2016]

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18. Shakibaie F, Walsh LJ. Violet and blue light-induced green fluorescence emissions from dental caries. Aust Dent J 2016;[in-press, accepted 28th Jan 2016] 19. Buchalla W, Lennon Ă M, Attin T. Comparative fluorescence spectroscopy of root caries lesions. Eur J Oral Sci 2004;112:490-496.

20. Buchalla W, Lennon Ă M, Attin T. Fluorescence spectroscopy of dental calculus. J Periodontal Res 2004;39:327-332.

21. Stambaugh RV, Myers GC, Ebling WV, Beckman B, Stambaugh KA. Endoscopic visualization of submarginal gingival root surfaces. J Dent Res 2000;79:600.

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Clinical significance of the anterior loop of the mental nerve: anatomical dissection of a cadaver population Muhammad A. Bobat1 and Ephraim R. Rikhotso2

Abstract Purpose: The anterior loop (AL) of the mental nerve is an anatomical structure that should be considered when placing dental implants in the region of the mental foramen. This study aimed to evaluate the presence and dimensions of the AL using anatomical dissection of cadaver specimens.

Materials and methods: 20 cadaver specimens were dissected bilaterally yielding 40 sides. The mental foramen was probed before accessing the AL in order to determine the relationship between probing and actual AL length.

The AL of the mental nerve was identified and measured through anatomical dissection.

Results: An AL was found in 22 sides (55%) with a range of 0,52mm to 4,29mm (Mean 1,18mm; SD 1,35mm).

Probing versus actual AL length revealed a weak negative correlation between AL length and probe depth.

Conclusions: The study has shown that clinically significant AL lengths can be present and implant planning must therefore account for these AL.

Keywords: Anterior loop; Mental nerve; Dental Implant; Maxillofacial List of Abbreviations AL Anterior Loop CBCT Cone Beam Computed Tomography SCT Spiral Computed Tomography

Introduction

Muhammad A. Bobat BDS (Wits), FCMFOS (SA), MDent (Wits) Department of Maxillofacial and Oral Surgery, University of the Witwatersrand, Johannesburg, South Africa

1

Ephraim R. Rikhotso BDS (Wits), FCMFOS (SA), MDent (Wits) Department of Maxillofacial and Oral Surgery, University of the Witwatersrand, Johannesburg, South Africa

2

Corresponding Author: Dr M. A. Bobat Email: Drbobat@mweb.co.za Contact Telephone: +27117045241 Fax: +27117045243

Dental implant placement in the region of the mental foramen has been known to cause neurosensory deficit due to nerve injury.1-4 The identification and preservation of the anterior loop (AL) of the mental nerve is an important means of avoiding such neurosensory deficit.5-7 There is a general consensus that plain film radiographs are inadequate for the accurate identification of the AL. Bavitz et al8 compared periapical radiographs to anatomical dissection on 24 cadaveric mandibles. They could not find a reliable relationship between the anatomical dissection and the periapical radiographs in determining the AL length. The radiographic examination revealed AL lengths of 0mm to 7mm while the anatomical dissection revealed AL lengths of 0mm to 1mm. A safety zone of 1mm was proposed to avoid injury to the mental nerve. Mardinger et al, in a similar study on 46 cadaveric hemi-mandibles showed that periapical radiography show false positive presence of an AL in 40% of the sample and failed to identify the AL in 70% of the sample.9 AL length ranged from 0,5mm to 2,95mm on periapical films and 0,4mm to 2,19mm on anatomical dissection. They proposed a safety zone of 3mm anterior to the mental foramen.

Alternative imaging modalities such as Spiral Computed Tomography (SCT), as well as Cone Beam Computed Tomography (CBCT), have been used for the identification of the AL. The proposed advantage of these techniques is their ability to create an accurate three-dimensional representation of the structure under investigation, thus eliminating the error of image distortion inherent in plain film radiography.10 Kaya et al11 evaluated 73 preoperative patients using panoramic radiographs as well as SCT

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Table 1. Proposed zone of safety Reference

Year

Methodology

Bavitz et al8

1993

Anatomical dissection Periapical radiography

1mm

Mardinger et al9

2000

Anatomical dissection Panoramic radiography

3mm

Kuzmanovic et al1

2003

Anatomical dissection Panoramic radiography

4mm

Li et al14

2013

SCT

5,5mm

for each patient. The radiographs and SCTs were evaluated for the presence and length of an AL bilaterally. Results showed that the SCT group identified a higher number of ALâ&#x20AC;&#x2122;s and the mean length of the AL was 3mm versus a mean of 3.71mm for the panoramic radiograph group. Li et al12 evaluated 68 SCTs of Chinese patients retrospectively and identified an AL in 83,1% of cases. The AL lengths ranged from 0mm to 5,31mm and the authors proposed a 5,5mm zone of safety to be maintained anterior to the mental foramen.

Uchida et al13 compared CBCT measurements to anatomical dissection and concluded that CBCT confers a high degree of accuracy when assessing the presence of an AL. Purely anatomical studies have been performed by a few workers. Rosenquist et al14 evaluated the AL in 58 patients who received inferior alveolar nerve transposition prior to implant surgery. They showed an AL of 0mm to 1mm with a mean of 0.15mm. Benninger et al15 in a study of 15 cadavers consisting of 30 sides showed the presence of an AL in only 4 sides, all of which did not exceed 1mm in length. They proposed that the large AL lengths previously described in the literature are anatomical aberrations, which are rarely encountered and thus the AL is of no clinical significance. Table 1 highlights the proposed safety zones postulated by various workers.1,8,9,14 The aim of our study was to evaluate whether a clinically significant AL does exist using anatomical dissection or whether the structure is of no clinical significance as has been recently asserted.

Proposed safety zone

by the University of the Witwatersrand Department of Anatomical Sciences.

Dissection Procedure The dissection was carried out by the same examiner for all specimens.

The dissection was performed on both sides of each mandible.

Soft tissues were reflected to expose the buccal surface of the mandible in the region of the mental foramen.

The mental foramen was probed using a Michigan probe, the depth of the infiltration of the probe was recorded. The buccal cortical plate was then removed to expose the inferior alveolar nerve and its branches.

The course of the inferior alveolar nerve was followed and if the nerve looped anterior to the foramen before exiting, this loop length was measured from the most anterior part of the loop to the anterior border of the mental foramen as shown in figure 1.

Materials and methods Population The study population consisted of cadaver specimens housed

Figure 1: Determination of AL length.

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Data Collection

Table 3. Anterior loop length

Data was recorded on a standard data capture form. Data was recorded for the left and right side of each specimen.

Probing depths: the anterior depth of the mental foramen was probed and measurements were recorded Anterior loop length: Any AL found was measured using a set of digital vernier calipers.

Right

Left

Minimum

1,01mm

0,52mm

Maximum

4,29mm

4,15mm

Data Analysis

Mean

2,12mm

2,18mm

The data was analysed using descriptive statistics and inferential statistics. The variables were grouped into Left and Right groups.

SD

1,00mm

1,26mm

Study Reliability All measurements were taken by the same examiner using the same set of instruments.

In order to test intraobserver reliability, repeat measurements were performed on 3 random specimens at the end of the data capture period.

The intraobserver error was noted at less than +/- 5% which was deemed acceptable.

Ethics The study is covered by Waiver W-CJ-101109-1 issued by the University of the Witwatersrand school of Anatomical Sciences and as such does not require ethical clearance for health research performed on donated bodies.

Results Demographics The study population consisted of 20 specimens whose age ranged from 35 years to 94 years with a median age of 63 years.

Probing of mental foramen related to anterior loop length Probing of the anterior part of the mental foramen yielded lengths ranging from 0mm to 8mm.

Table 2. Frequency of AL Right

Left

No AL

9

9

AL present

11

11

A Spearmanâ&#x20AC;&#x2122;s rank correlation test was performed which revealed an R-value of -0,0015. This shows a weak negative correlation between probing the mental foramen and the actual AL length.

Anterior Loop Data Anterior loop frequency Table 2 shows the frequency of AL found in 40 sides of the dissected specimens. The AL was found in 55% of the sample and absent in the remaining 45%.

Anterior loop length In those specimens where an AL was present, the length ranged from 1,01mm to 4,29mm (Mean 2,12mm; SD 1,00mm) on the right side and 0,52mm to 4,15mm (Mean 2,18mm; SD 1,26mm) on the left side. The combined mean value for all 40 sides was 1,18mm and the SD was 1,35mm.

The descriptive statistics for the AL are reported in Table 3.

A correlation test was performed which showed a 72,01% chance of the AL having a similar length as the contralateral side.

Discussion Probing In this study we found that probing the mental foramen does not allow for accurate identification of an AL. The lack of correlation between probing the mental foramen and the AL collaborates the findings of a previous study16, therefore it is unreliable and not recommended that the presence of an AL be determined at the time of surgery using direct probing.

Reasons for this might include perforation of the medullary bone with the instrument tip, or the instrument tip inadvertently entering the incisive canal when there is no AL present.

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Figure 2a shows the morphology of the mental nerve where no AL is present.

Figure 2b shows the morphology of the mental nerve where an AL is present – note the branching rather than looping pattern.

Anterior Loop

Further studies comparing anatomical dissection and CBCTs may give more clarity on the dimensions and clinical significance of the AL of the mental nerve.

In this study, the AL was found in 55% of the sample and the length ranged from 0,52mm to 4,29mm (Mean 1,18mm; SD 1,35mm), however AL of 4mm or greater was found in 3 sides. There was a 72,01% chance that the AL on the contralateral side would be of equal length. An interesting observation was that the morphology of the AL was not a loop. The AL branched off the inferior alveolar nerve acutely and did not curve or loop as it passed toward the mental foramen. This is similar to the finding reported by Benninger et al15 and perhaps indicates that the term ‘anterior loop’ is a misnomer since the actual morphology of this structure is a branch rather than a loop. Examples of this pattern are shown in Figure 2.

The AL range found in this study is contrary to those reported by Benninger et al15 who found only 4 AL in 26 sides, all of which did not exceed 1mm in length. Even though there were no loops as large as those previously reported by Uchida et al13 (9mm) the presence of loops greater than 4mm are significant and could have an impact on implant placement anterior to the mental foramen.

Conclusion This study suggests that a weak negative correlation between probing the mental foramen and the actual AL length exist. Also, it appears that an observance of a 5mm safety zone (unless confirmed otherwise by 3D imaging such as CBCTs) or shorter implants are a safer option when it comes to implant placement anterior to the mental foramen.

References 1. Kuzmanovic DV, Payne AG, Kieser JA, Dias GJ. Anterior loop of the mental nerve: a morphological and radiographic study. Clin Oral Implants Res 2003;14(4):464-471.

2. Bartling R, Freeman K, Kraut RA. The incidence of altered sensation of the mental nerve after mandibular implant placement.

J Oral Maxillofac Surg 1999;57(12):1408-1412.

3. Wismeijer D, van Waas MA, Vermeeren JI, Kalk W. Patients' perception of sensory disturbances of the mental nerve before and after implant surgery: a prospective study of 110 patients. Br J Oral Maxillofac Surg 1997;35(4):254259.

4. Walton JN. Altered sensation associated with implants in the anterior mandible: a prospective study. J Prosthet Dent 2000;83(4):443-449.

5. Arzouman MJ, Otis L, Kipnis V, Levine D. Observations of the anterior loop of the inferior alveolar canal. Int J Oral Maxillofac Implants 1993;8(3):295-300.

6. Ngeow WC, Dionysius DD, Ishak H, Nambiar P. A radiographic study on the visualization of the anterior loop of the mental nerve in dentate subjects of different age groups. Journal of Oral Science 2009;51(2):231-237.

7. Greenstein G, Tarnow D. The Mental foramen and nerve: clinical and anatomical factors related to dental

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implant placement: a literature review. J Periodontol 2006; 77(12):1933-1943.

8. Bavitz JB, Harn SD, Hansen CA, Lang M. An anatomical study of the mental neurovascular bundleimplant relationships. Int J Oral Maxillofac Implants 1993;8(5):563–567.

9. Mardinger O, Chaushu G, Arensburg B, Taicher S, Kaffe I. Anterior loop of the mental canal: an anatomicalradiologic study. Implant Dent 2000;9(2):120-125.

10. Tyndall DA, Price JB, Tetradis S, Ganz SD, Hildebolt C, Scarfe WC. Position statement of the American Academy of Oral and Maxillofacial Radiology on selection criteria for the use of radiology in dental implantology with emphasis on cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;113(6):817-26.

11. Kaya Y, Sencimen M, Sahin S, Okcu KM, Dogan N, Bahcecitapar M. Retrospective radiographic evaluation of the anterior loop of the mental nerve: comparison between panoramic radiography and spiral computerized tomography.

Int J Oral Maxillofac Implants 2008;23(5):919-925.

12. Li X, Jin ZK, Zhao H, Yang K, Duan JM, Wang WJ.

The prevalence, length and position of the anterior loop of the inferior alveolar nerve in Chinese, assessed by spiral computed tomography.

Surg Radiol Anat 2013;35(9):823-830.

13. Uchida Y, Noguchi N, Goto M, Yamashita Y, Hanihara T, Takamori H, et al. Measurement of anterior loop length for the mandibular canal and diameter of the mandibular incisive canal to avoid nerve damage when installing endosseous implants in the interforaminal region: a second attempt introducing cone beam computed tomography. J Oral Maxillofac Surg 2009;67(4):744-750.

14. Rosenquist B. Is there an anterior loop of the inferior alveolar nerve? Int J Periodontics Restorative Dent 1996;16(1):40-45.

15. Benninger B, Miller D, Maharathi A, Carter W. Dental implant placement investigation: is the anterior loop of the mental nerve clinically relevant? J Oral Maxillofac Surg 2011;69(1):182-185.

16. Neiva RF, Gapski R, Wang HL. Morphometric analysis of implant-related anatomy in Caucasian skulls. J Periodontol 2004;75(8):1061-1067.

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Rebilda Post GT allows a customised and at the same time substance-preserving restoration, as the fine individual posts can be distributed throughout the entire root canal following removal of the sleeve and then adapt optimally to the respective root canal morphology. Root canal enlargement with a drill for a correspondingly sized post is thus not necessary, meaning that no additional tooth substance is lost, which would inevitably result in weakening of the root structure. Its unique composition makes Rebilda Post GT particularly suitable for use in non-round root canals and in root canals prepared using a larger cone in the greater taper technique, from which the “GT” in the product name is derived.

Following pre-treatment of the root canal, the cluster of posts is silanised, coated with luting composite and then inserted into the root canal filled with luting composite. Prior to polymerisation of the luting composite, the sleeve is removed, so that the individual posts can be fanned out throughout the canal using a suitable instrument. This spreading out of the posts leads to both homogeneous reinforcement of the luting composite throughout the length of the root canal and an increase of the contact surface with the buildup composite in the coronal region, which results in a high degree of stability for the post/build-up system overall.

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9th International Quintessence Symposium 2016 on Periodontics & Restorative Dentistry â&#x20AC;&#x201C; Science meets practice including a special program on adhesive dentistry As this is the 9th time the symposium has visited Australia, it is remarkable that the quality of the speakers and their presentations keeps getting better. The high regard in which the symposium is held globally is quantified by the commitment of the well-known speakers who are prepared to take the time out of their practices to make the long trip to Australia and participate in this event.

The concurrent adhesive dentistry program was so well attended that extra chairs needed to be brought into the lecture theatre. This program was designed based on the feedback from delegates in 2014 and it proves that not only are the program designers listening to the requests of delegates but also shows how the symposium taps into dentistry today and the educational needs of the attendees.

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The program theme “Science Meets Practice” gave delegates the information they needed to improve procedures in their daily practice right away.

The program was wonderfully moderated by the scientific chairman Professor Laurie Walsh with assistance from local Queensland colleague, Professor Ian Meyers. During the adhesive program we were delighted to welcome Professor Markus Blatz who not only presented but moderated for the day.

High praise from delegates went to Pat Allen for his lecture on Cervical Lesions: Guidelines for When to Graft and When to Restore which answered all the tricky questions people are hesitant to ask but need to know.

Another popular lecture, Bonding Capacity of Luting Agents to Alloys and Ceramics in Adhesive Prosthodontics was delivered by Professor Matthias Kern during the Adhesion program. His workshop on the Sunday was another stand out for the morning. Participants raved about the opportunity to break into intimate groups where personalised instruction and discussions took place.

Further reinforcing the relevance of the program to everyday practice, Professor Frank Schwarz spoke on how to avoid and manage peri-implant diseases. During his hands on workshop on Sunday morning, delegates were able to practice indication based flap and suturing techniques proposed for hard and soft tissue augmentation.

"The International Quintessence Symposium was a very well-run and highly enjoyable event. It was very informative as it covered all the latest updates and researches in the implant, Periodontics, and adhesive dentistry discipline. I would highly recommend it to all Dentists." Dr Andrew Wang, Bronte NSW "Of the many conferences, symposia, courses and seminars that I attend the standout symposium and one that I make a point of always attending, in fact I haven't missed one is Quintessence. If you want a general overview of what is cutting edge in dentistry at that moment you really can't go past the Quintessence Symposium with an impressive line-up of speakers and quality hands on workshops" Dr Greg Doucas, Midland WA Watch out for 2018 dates which will be released soon, it’s the perfect way to earn your entire cycle of CPD hours in one weekend! If you would like to register your interest now please email events@henryschein.com.au

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Direct restoration in the aesthetic zone a case study

Neil Gerrard1

The patient, a 27-year-old female in good health, presented to the practice requesting improvement of her smile.

She requested alignment of her anterior teeth and improvement to the general colour of her smile – in particular the shade of existing composite restorations that had been carried out on teeth UR1 and UL1. Both teeth had previously been treated with direct composite in order to mask enamel hypoplastic white spots as a teenager.

Diagnosis On examination it was noted that her general dental health was good, with no existing restorations (other than those at UR1/UL1), no carious lesions and no loss of clinical attachment of periodontal tissues (though general gingivitis was diagnosed).

Closer examination of the teeth confirmed widespread hypoplastic white enamel spots on both anterior and posterior teeth. Some minor brown spot lesions were also noted on teeth UR2 and UL2, as was pitting of the enamel on teeth UL3/UL4. On questioning, no obvious cause – such as ingestion of fluoride toothpaste as a child, for example – of the white spots could be established, only that the incisal third of each central incisor were the teeth most obviously affected and subsequently treated.

The presenting appearance of this case suggested that fluoride ingestion was the most likely cause, leading to a diagnosis of mild fluorosis being made.

Treatment plan

1

Dr Neil Gerrard BDS RDT MSc Private Practice, Bristol, UK

The patient presented with a number of concerns relating to her smile, including alignment of the anterior teeth as well as general shade, and the shade of existing restorations. The patient’s aim was to achieve a straighter, whiter smile with an even colour to teeth UR1 and UL1.

A number of treatment options were therefore presented to the patient, including: 1. Pre-restorative alignment of the teeth with either fixed or removable (clear aligner) orthodontic appliance therapy. Following this, general tooth whitening followed by replacement of existing composite at UR1/UL1 with direct composite better representing the new shade of the natural dentition for seamless integration into the smile 2. An alternative to pre-restorative alignment of the smile was to complete general whitening of the smile, followed by placement of direct composite (partial and full coverage veneers) in order to correct shade as well as form and alignment (with or without minimal preparation as required) 3. As per option two, but utilising indirect minimal prep ceramic veneers.

Option one was deemed the most conservative approach, option three the most aggressive.

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Figure 2: Smile view (1:2, anterior)

Figure 2: Smile view (1:2, anterior)

Figure 1: Full face view

Figure 4: Smile view (1:2, left)

Figure 5: Retracted view (1:2, anterior)

Figure 6: Retracted view (1:1, anterior)

Figure 7: Retracted view (1:1, right)

Figure 8: Retracted view (1:1, left)

Figure 9: Upper occlusal view

Figure 10: Lower occlusal view

After considering all options, the patient chose to proceed with pre-restorative alignment utilising a labial fixed appliance, followed by whitening and subsequent replacement of the existing composite.

Treatment sequence and description Prior to any restorative treatment, the patient was referred to a colleague for aesthetic orthodontic alignment of both upper and lower dental arches.

A non-extraction approach was taken, using a

combination of interproximal reduction (IPR) and rounding out of the arch forms to achieve alignment (while trying to minimise dumping of the anterior teeth forward).

Following successful alignment, the patient was referred back to the author for post-alignment whitening and restorative care. Alignment of both arches had been successfully achieved, with little evidence of any significant proclination of the maxillary teeth.

However, some residual space, of approximately 1mm, was noted distal to tooth UR2. It had been noted that without

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GERRARD

Figures 11 and 12: Preparation

further aggressive IPR and retraction to the lower incisor teeth, this space could not be closed. Following discussion with the patient prior to debonding of the fixed labial appliance, the patient agreed to a compromise – that of direct composite bonding to the distal surface of the UR2 – to both minimise excessive enamel removal to the interproximal surfaces of the lower incisors, and to speed up completion of treatment.

Tooth whitening The patient undertook a course of home tooth whitening using custom made trays and 16% carbamide peroxide.

The patient was instructed to use the trays for approximately four weeks each night to brighten the teeth, then stop for two weeks prior to the restorative phase in order to account for rebound (Kugel et al, 2009).

The patient had also been preoperatively advised that due to the nature of hypoplastic spots, that these would likely appear worse in the short-term until the full whitening effect had been achieved. The patient had also been advised that the appearance of the white spots would not fade, only that the contrast between the ‘normal’ enamel and hypoplastic enamel would reduce as the enamel became brighter.

Review of the patient at two weeks post-whitening confirmed a much improved result, of which the patient was very happy despite the appearance of multiple white spot lesions still being evident. Assessment with a bleaching shade guide (Ivoclar Vivadent) confirmed a new shade approximating that of BL3 (compared to the original body shade of A2), suggesting that a very acceptable result had been achieved. A two-week cessation of whitening prior to direct composite placement will also minimise any potential effects on resin bond strengths which may lead to premature bond failure (Li, Greenwall, 2013).

Resin infiltration of the enamel surface using a system such as Icon by DMG has been shown to treat the appearance of hypoplastic spots effectively. This was offered to the patient prior to replacement of the direct composite on UR1/UL1 with the view to completely masking the white spots, or significantly reducing their visual impact.

The patient declined such treatment, stating that she was very happy with the aesthetic appearance of all teeth other than that of UR1/UL1.

Treatment therefore proceeded as planned with replacement composite to UR1/UL1 and direct diastema closure distal to UR2. Importantly, the patient agreed that in order for any new restoration to blend seamlessly with the natural dentition, it would need to include and replicate hypoplastic regions.

Preparation phase In preparation of the restorative phase, a diagnostic wax-up on stone casts was completed, and the laboratory instructed to mimic the general form of the UR1/UL1 regarding the incisal silhouette and incisal width.

This would enable the use of a putty stent for accurate replication of anatomical forms of both teeth, in which composite could be layered into and thus create a thin palatal shell/silhouette from which to aid an additive technique (requiring minimal contouring and adjustment post placement) (Devoto et al, 2010).

In order to compensate for a change in value as a result of desiccation of the teeth during treatment, a diagnostic composite mock-up (physical colour map) was completed at the very beginning of the treatment session on the labial surface of the UL1 in order to confirm shade and value accurately. Once confirmed, this prescription would be

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Figure 14: Smile view (1:2, anterior)

Figure 15: Smile view (1:2, right)

Figure 13: Full face view

Figure 16: Smile view (1:2, left)

Figure 17: Retracted view (1:2, anterior)

Figure 18: Retracted view (1:1, anterior)

Figure 19: Retracted view (1:1, right)

Figure 20: Retracted view (1:1, left)

Figure 21: Upper occlusal view

followed regardless of the appearance of the adjacent teeth, which would likely increase in value, and with an even greater number of white spot regions developing as treatment progressed (a result of dehydration).

In order to counter this, a pre-restorative photo would also be referred to as the pattern and distribution of the existing white lesions on adjacent teeth.

The existing composite was removed with multi-fluted carbide burs, under magnification and without water in order to visualise the existing composite interface with the underlying tooth substrate. Approximately one third of the

Figure 22: Lower occlusal view

width of labial surface appeared to have been removed when the original composite restorations were placed, exposing some minor regions of dentine.

Direct composite bonding The composite resin of choice in this case was HFO. The colour map indicated a basic chromacity of UD1 and UD0.5, with an enamel layer of medium high value GE3.

Opalescent white incisal (OW) was also found to mimic the existing enamel, while IW (opaque white intensive effect) was chosen to represent areas of hypocalcification.

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A mildly textured surface was noted on all incisors with a view to mimicking this as closely as possible in order to integrate the restorations.

Preparation of the tooth surface prior to bonding included the placement of bevelled margins (where possible) to the buccal and lingual surfaces with a finishing diamond bur (to aid integration of the restoration reducing appearance of marginal edges), followed by air-abrasion utilising 27µm alumina oxide to maximise bond strengths.

A partial etch technique using 37% phosphoric acid was employed to prepare the enamel for a maximum of 30 seconds. Following this, a self-etching bonding resin was used to complete bonding to the etched enamel surface, but also create a bond to the dentine surface for improved dentine bond durability over time as a result of MMP reduction compared to a total etch technique (Mazzoni et al, 2013; Reis et al, 2013).

With the putty matrix in position, HFO composite resin was incrementally layered to the correct anatomical form. GE3 enamel was layered first into the matrix, then cured against the tooth. This was then followed by body composites UD1 and UD0.5 until the basic dentinal form was achieved (including mammelon forms).

Even though the optical properties of enamel had been modified with preoperative whitening, these layers still exist and thus require mimicking if an accurate shade match is to be achieved. Prior to layering of the labial enamel increment, IW intensive white was placed in a form to mimic the natural hypoplastic regions of adjacent teeth. As with all intensive effects, this was placed sparingly, as the subsequent addition of the enamel layer magnifies such effects. The final enamel layer consisted of GE3 and a thin layer of OW to help replicate the shade, while blending the composite with the body of the tooth.

The same process was used to directly bond composite to the distal surface of the UR2, though care not to etch the mesial surface of the UR3 was taken. By avoiding etching of the canine, composite could be directly layered to the mesial surface forming an intimate contact point. This can then be separated by spreading the teeth between the contacts, followed by the use of flexi-discs in order to achieve the desired final form.

The utilisation of the putty matrix normally means that little finishing is required following placement of the composite resin. The minor finishing required for this case was achieved with abrasive discs, rubber polishing points and fine diamond burs.

To complete the restoration some minor secondary and

tertiary anatomical features were created. Polishing was completed with 3µm and 1µm diamond pastes, followed by aluminum oxide to achieve a natural high lustre to the restoration.

Convex surface anatomy was created with flexi-discs to produce a smooth natural finish to the restoration and enamel-composite junction.

Functional occlusion was checked and adjusted with 100µm paper while seating the patient at a 45o angle and asking them to chew. But as the new restorations essentially followed the natural incisal silhouette, little adjustment was required.

Finally, the patient was provided with a new removable orthodontic retainer and whitening tray to fit the modified tooth forms.

Conclusion On immediate completion of the procedure, such significant desiccation of the enamel had occurred that the true shade could no longer be determined with white regions significantly exaggerated. The patient was therefore invited back for a review a few days later in order to confirm accurate shade replication following rehydration of the enamel surfaces. In this instance, the restorations proved to be a successful match and the patient was delighted with the results.

The above case study was a winner of an Aesthetic Dentistry Today 2016 (UK) award.

References Devoto W, Saracinelli M, Manauta J (2010) Composite in everyday practice: how to choose the right material and simplify applicationtechniques in the anterior teeth. The European Journal of Esthetic Dentistry 5(1): 2-23 Haywood V (1992) History, safety, and effectiveness of current bleaching techniques and application of the nightguard vital bleaching technique. Quintessence Int 23(7): 471-488 Kugel G, Ferreira S, Sharma S, Barker M, Gerlach RW (2009) Clinical Trial Assessing Light Enhancement of In-office Tooth Whitening. Journal of Esthetic and Restorative Dentistry 21(5): 336-347 Li Y, Greenwall L (2013). Safety Issues of Tooth Whitening Using peroxide-Based Materials. British Dental Journal 215(1): 29-34 Mazzoni A, Scaffa P, Carrilho M, Tjaderhane L, Di Lenarda R, Polimeni A, Tezvergil-Mutluay A, Tay FR, Pashley DH, Breschi L (2013) Effects of Etch-and-Rinse and Self-Etch Adhesives on Dentine MMP-2 and MMP-9. J Dent Res 92(1): 82-86 Reis A, Carrilho M, Breschi L, Loguercio A (2013) Coverview of Clinical Alternatives to Minimize the Degradation of the Resin-Dentin Bonds. Oper Dent 38(4): 1-25

Reprinted with permission by ADT October 2016

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Making sense of mouth ulceration: Ulceration of local cause Crispian Scully1

Ulceration of local cause Most oral ulcers/erosions are due to local causes, such as trauma or burns, and few of those affected attend a dental professional for advice. Ulceration of local cause includes trauma, burns, mucositis and local lesions.

Trauma • • • • • • • • •

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.

Abuse Accidents Anaesthesia (after local anaesthesia, or neurological) Assaults Bites (Figure 1) Cunnilingus Falls Fellatio Self-harm (factitious).

In children, ulcers are often caused by accidental biting, follow dental treatment or other trauma, or from hard foods or appliances (Figure 2).

In child abuse (non-accidental injury), ulceration of the upper labial fraenum may follow a traumatic fraenal tear. Bruised and swollen lips, and even subluxed teeth or fractured mandible, can be other features of child abuse.

The lingual fraenum may be traumatised by repeated rubbing over the lower incisor teeth in children with recurrent bouts of coughing, as in whooping cough or in self-harm and self-mutilating conditions.

Trauma can produce ulceration in adults. Ulcers can be induced by a sharp tooth, restoration or appliance. Ulceration from the flange of a denture or other appliance is common – the close location and time relationship to appliance wearing is usually obvious (Figures 3a and 3b).

Chronic trauma may produce an ulcer with a keratotic or hyperplastic margin. If the lesion is suspicious, it should be observed for two weeks after the suspected irritant factor is removed and, if not resolved, should be biopsied.

Far less obvious is ulceration of the lingual fraenum if damaged in cunnilingus, or the palate in fellatio.

At any age there may be ulceration where there is pain-insensitivity (congenital or acquired – especially after a local anaesthetic), or in mental health disorders there may be factitious ulceration, especially of the maxillary gingivae.

Burns • Chemicals • Thermal • Radiation.

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Figure 1: Ulceration related to trauma

At any age there may be ulceration caused by local burns with chemicals of various kinds, thermal injury (hot or cold), or radiation damage (laser, light or ionising radiation) – and also after cytotoxic chemotherapy or after graft-versus-host disease – a systemic reaction mainly seen after bone marrow transplantation (then termed mucositis).

Chemicals that have been implicated in ulceration include: • Bleach, especially hypochlorite • Choline salicylate • Denture cleansers • Formalin • Liquid nitrogen • Medication burns (eg, ferrous sulphate) • Mouthwash overuse • Peroxides • Phosphoric acid • Sulphuric acid • Root canal medicaments.

Burns are characterised by mild to moderate tissue damage and often heal spontaneously within seven to 10 days, usually without scarring.

Figure 2: Ulceration related to orthodontic appliance

• Alcohol • Concurrent chemotherapy • Dental disease • Poor oral hygiene • Younger age.

Radiation mucositis can be reduced by using: • New radiation techniques • Minimal radiation doses and field • Mucosa-sparing blocks • Amifostine before therapy • No chemotherapy • Betamethasone mouthwashes.

Treatment includes avoiding irritants (smoking, spirits or spicy foods), good oral hygiene, as well as analgesics: • Topically prior to meals – 1.5% benzydamine hydrochloride spray or mouthwash – 2% lidocaine (lignocaine) mouthwash – Aspirin as a mouthwash • Systemically – Opioids, such as morphine, buprenorphine or hydromorphone.

Local lesions Mucositis Radiation-induced mucositis is common and invariable within the radiated field of mucosa. Chemotherapy mucositis will be discussed later in this series.

Mucositis can lead to a number of problems, including ulceration and can be lethal by acting as a portal for septicaemia, especially streptococcal.

Risk factors for radiation mucositis are mainly the radiation dose and type of fractionation but may also include:

Necrotising sialometaplasia Necrotising sialometaplasia (NSM) is a rare condition of ulceration, often in the palate, which heals spontaneously over several weeks. Usually seen in smokers, it is associated with salivary gland infarction.

Since the clinical features may mimic squamous cell carcinoma, biopsy is indicated if the ulcer persists for more than three weeks; this may have an appearance resembling neoplasia (pseudoepitheliomatous hyperplasia). There is

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Figures 3a and 3b: Denture-induced ulceration and hyperplasia

infarction, metaplasia, and the lesion is negative for p53, but positive for Ki-67, CK7 and p63 (4A4), and calponin negative myoepithelial cells. If it fails spontaneously to resolve, treatment with surgery may be necessary.

Traumatic ulcerative granuloma with stromal eosinophilia (TUGSE) TUGSE is not related to eosinophilic granuloma of bone as in Langerhans cell histiocytosis.

A reactive condition probably due to trauma, TUGSE typically presents as a deep, rolled bordered and indurated ulcer or can be exophytic and lobular (like a pyogenic granuloma) but usually resolves spontaneously slowly over many weeks, although it may recur.

Seen most commonly on the dorsal and lateral tongue, followed by lips and buccal mucosa, it may affect patients of all ages, including neonates (Riga-Fede disease).

Since the clinical features may mimic squamous cell carcinoma, biopsy is indicated if the ulcer persists for more than three weeks; this shows eosinophils in areas of muscle damage. Treat with surgery, and intralesional corticosteroids if it recurs.

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. Wiley-

Blackwell (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 978-0-702-04649-0 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

Disclosure This series offers a brief synopsis of the diagnosis and management of mouth ulceration – a complex topic that includes common disorders, and less common but lifethreatening conditions. It does not purport to be comprehensive, and the series may include some illustrations from books written or co-authored by the author and colleagues from UK and overseas, published by Elsevier-Churchill Livingstone, WileyBlackwell, or Informa/ Taylor & Francis – all of whose cooperation is acknowledged and appreciated.

Published with permission by Private Dentistry October 2014

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Non-surgical retreatment of a central incisor following dental trauma John Rhodes1

Introduction A 20-year-old woman was referred suffering from occasional, spontaneous toothache around the maxillary right central incisor (UR1). This radiated to an area underneath the nose and varied in intensity, but could be sufficiently bad to disrupt normal activity, such as driving a car. She was unable to bite on the tooth without discomfort.

When she was nine years old, she had tripped and fallen onto a post, traumatising the UR1 and causing an enamel-dentine fracture that did not expose the pulp.

From the patientâ&#x20AC;&#x2122;s perspective everything appeared to be fine until about three years after the accident, when the UR1 started to become painful to bite on and the gum was sore. The general dental practitioner root filled the tooth and it settled down.

More recently, this young lady had become very conscious of the tooth darkening and sought the opinion of a new dentist to see whether a veneer was feasible. When a periapical radiograph was exposed it showed a poor root filling and large apical radiolucency.

Her medical history was uncomplicated, and apart from an allergy to penicillin, she was fit and well.

This article describes the non-surgical retreatment of a central incisor that had previously suffered trauma. The immature root was managed using a biological approach with micro-endodontic techniques.

Clinical examination

1

John Rhodes is a specialist in endodontics, author of textbooks, numerous papers and owner of The Endodontic Practice Poole and Dorchester. He lectures and teaches on endodontics nationally.

Intraoral examination revealed that the UR1 was tender to percussion. It was not abnormally mobile nor was it ankylosed. The colour was significantly darker than the adjacent incisor teeth with a Vita equivalent shade of C3/C4 compared with healthy teeth at A2.

Photographs were taken for patient records at this point. There was an incisal/buccal composite restoration that was no longer a good colour match and had visible margins.

Soft tissue examination revealed no buccal swelling but the mucosa was tender over the apex of UR1 and a sinus tract was present.

Sensitivity testing with Endo-Ice (Coltene) and electric pulp testing (Sybronendo Diagnostics Unit) revealed that the UR1 was the only non-vital incisor tooth.

Paralleling periapical radiographs were exposed of the central incisor teeth using a Rinn Holder (Rinn, Dentsply) and all looked normal apart from the UR1. An attempt had been made to root fill the UR1 but the obturation material was significantly undercondensed in the apical third, and individual gutta percha cones were visible.

The dentist had clearly had difficulty managing the immature canal. They may also not have had confidence fitting rubber dam on a 12-year-old, increasing the potential for bacterial contamination of the root canal. The coronal restoration provided an inadequate seal. The root length of UR1 was significantly shorter than the UL1 and a large radiolucent area was present at the apex. No evidence of replacement resorption,

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Figure 1: Shows the maxillary anterior teeth. The UR1 is noticeably discoloured.

Figure 2: A paralleling radiograph showing the root filling in UR1 and large periapical raiolucency.

Figure 3: A microsope view into the access cavity; IRM has been placed over the Biodentine to act as a barrier for placement of bleaching material.

Figure 4: Endoperox, a carbamine peroxide material for internal bleaching.

inflammatory resorption, or any root fractures could be detected.

the patient could expect the tooth to remain functional for many years. Replacement at an early age with an implant may provide a good cosmetic result initially, but over a lifetime the result would be difficult to predict.

Generally, well root filled and restored teeth appear to function as well as single tooth implants and result in less costly repairs when things fail (Hannahan and Eleazer, 2008; Pennington et al (2009); Torebinejad et al, 2007).

The dark colour of the tooth (and the main complaint of the patient) could be improved by: • Internal bleaching • Internal/external bleaching using trays • Placement of a veneer in composite or porcelain • Placement of a crown.

Bleaching techniques are low risk, and non-invasive (Zimmerli, Jeger and Lussi, 2010). Bleaching would, therefore, be the preferred means of improving tooth colour.

Diagnosis Although there was history of trauma, the most likely cause of current symptoms and clinical findings was periapical periodontitis.

The root canal filling had most probably failed as a result of persistent bacterial infection in the root canal. The tooth had not undergone replacement or inflammatory resorption.

Treatment options The treatment options were as follows: 1. Root canal retreatment and restoration with composite 2. Extraction and replacement with a Maryland bridge or implant-supported crown.

The prognosis for root canal retreatment should be good and

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6

Figure 5: The completed restoration following bleaching

Matching the texture and colour of adjacent teeth with a porcelain or composite veneer on a single tooth would be aesthetically challenging and preparation of a crown unjustifiably destructive.

After discussion with the patient an internal bleaching technique was the option of choice.

Treatment Due to the history and chronicity of the infection, a two-visit strategy was adopted. This ensured adequate disinfection of the root canal and the possibility to confirm healing of the sinus tract before obturation.

Buccal infiltration of 4% articaine 1:100,000 adrenaline (Septodont) provided profound anaesthesia and the UR1 was isolated with latex rubber dam and a number one clamp.

Using an operating microscope the existing filling was removed with a long-tapered diamond bur, and soft dentine (the result of microleakage) with a tunstgen carbide LN bur (Dentsply). This revealed a contaminated root canal containing poorly condensed gutta percha. The root filling was rapidly removed with Gates Glidden size two and Hedstroem file size 30 (Dentsply Maillefer). The loose gutta percha points were washed out of the canal with sodium hypochlorite.

The apical foramen of the canal was large (greater than a size 40 file) and could be visualised through the operating microscope. The coronal access was refined and a working length estimation made with an apex locator (Endo Analyzer, Sybron) and size 40 Flexofile (Dentsply Maillefer). A steady zero reading was achieved and this was confirmed by direct sight.

Because the root had an immature morphology there was

7

Figure 6: A radiograph showing the completed non-surgical retreatment. There is good homogeneity between the various layers of material.

Figure 7: The review radiograph at three months shows evidence of a reduction in the size of the periapical radiolucency. This, combined with absence of clinical signs and symptoms, indicates good early signs of successful treatment

no requirement for mechanical instrumentation. Instead, the canal was disinfected with a solution of heated 3% sodium hypochlorite (Teepol) irrigant, delivered using a safe-ended needle (Henry Schein) bent short of the working length to prevent extrusion.

Disinfection was carried out over approximately 40 minutes. The sodium hypochlorite was agitated with a size 20 Irrisafe ultrasonic tip (Satelec) and an Endoactivator (Dentsply Maillefer) with a blue tip. The solution was replenished every two minutes. A final sequence with 40% citric acid (Cerkamed) and 3% sodium hypochlorite completed irrigation.

The canal was dried with sterile paper points (Dentsply Maillefer) and non-setting calcium hydroxide placed (Calasept). The access was sealed with a cotton wool pellet at the level canal orifice, Cavit (ESPE) and Fuji IX (GC).

One week later the sinus had healed, the tooth was symptom free, the canal dry, odour-free, and the tooth ready for obturation.

The apical portion of the canal was sealed with Biodentine (Septodont), packed into place using a Machtou plugger with the microscope providing direct vision. On top of this, a layer of IRM (Dentsply) was placed.

Endoperox (Septodont) internal whitening agent was mixed and packed into the access cavity. This was then sealed with Fuji IX compomer.

After a further week the tooth was reviewed. The tooth was symptom free and the patient was happy with the colour, so the access was permanently restored with Fuji IX, light-cured

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bulk fill composite SDR (Smart Dentine Replacement, Dentsply) and Ceram-X Duo (Dentsply). The incisal tip was restored with Ceram-X Duo. The tooth was reviewed at three months, when it was symptom and sinus free and a paralleling radiograph showed good evidence of early bony healing at the apex.

A further review will be carried out at one year and subsequently at two and four years or when bony healing is complete.

Discussion The International Association for Dental Traumatology (IADT) has produced guidelines for the management of traumatic injuries to teeth, available online as the dental trauma guide (2010).

The recommended treatment for an enamel-dentine fracture is as follows: 1. If a tooth fragment is available, it can be bonded to the tooth. Otherwise, perform a provisional treatment by covering the exposed dentine with glass-ionomer or a permanent restoration using a bonding agent and composite resin 2. The definitive treatment for the fractured crown is restoration with accepted dental restorative materials 3. Three angulations (periapical, occlusal and eccentric exposures) should be used in the radiographic examination to rule out displacement or fracture of the root 4. Radiograph of lip or cheek lacerations to search for tooth fragments or foreign material 5. Follow-up – clinical and radiographic control at six to eight weeks and one year The importance of checking adjacent teeth cannot be overemphasised as it is not uncommon for collateral damage to have occurred as a result of trauma.

Data from the dental trauma guide shows prognosis for an enamel-dentine fracture at one to three years to be very good, with the risk of pulp necrosis to be only extremely low.

This suggests that the initial injury in this case may have been more severe. The root length of UR1 was shorter than UL1 and the root morphology immature, suggesting that root development had stalled shortly after injury.

Ravn (1981) evaluated the prognosis for permanent incisors with enamel-dentine fracture only and those with enamel-dentine fracture combined with other factors. Pulp death occurred in 3.2% of teeth with enamel-dentine fracture as the only damage. Enamel-dentine fracture and concussion resulted in pulpal necrosis in 5.8%, and cases involving both concussion and mobility showed pulpal necrosis in 30.1%

of teeth.

Teeth with combined intrusion injuries would have a much higher incidence of pulp necrosis (67.6% at one year and 70.9% at three years), inflammatory root resorption approximately 35% at one and three years, and ankylosis 8.8% at one year and 12.1% at three years (Diangelis et al, 2012).

This confirms the requirement for meticulous examination of dental trauma cases and the potential risk of combined injuries. Compliance of the patient and parents to attend review is critical.

Limited volume, high resolution cone beam tomography can be useful in the assessment of trauma cases and the detection of resorption defects in endodontics. Evidence based guidelines for the clinical use of CBCT, known as the European Commission Radiation Protection guidelines (SEDENTEXCT 2012), and those from the American Association of Endodontists (2011), both recommend that the need for a CBCT scan should always be assessed after a risk versus benefit analysis before each exposure.

In this case, the tooth had been traumatised 11 years earlier; it was not ankylosed and showed no sign of inflammatory resorption clinically or on radiograph. The risk of both following trauma is highest in the first three years (Diangelis et al, 2012).

It was therefore considered more likely that the tooth had become necrotic after injury and the radiolucent area was the result of apical periodontitis; this was also confirmed by the presence of a sinus tract. The root canal was likely to be infected with bacteria and so there was no indication to expose a CBCT scan at this stage.

It is important in root canal retreatment to remove the failed root canal filling material as efficiently as possible to allow disinfection of the root canal (Van Nieuwenhuysen, Aouar and D’Hoore, 1994). During retreatment the existing material and any obstructions and missed canals should be prepared and disinfected at the first visit.

Two-visit approach Historically, it has been shown that mechanical preparation alone reduces the bacterial load in an infected root canal, according to Byström and Sundqvist, (1981) but sodium hypochlorite in a concentration of at least 1% is required to kill any remaining bacteria (1983). Sodium hypochlorite also dissolves necrotic pulp tissue. The bacteria are present in planktonic form and as a biofilm; the latter are surrounded by matrix and can be difficult to remove.

The irrigant must therefore be agitated to break up these

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bacterial aggregations. Ultrasonic activation removes more debris from the root canal than syringe irrigation alone (Burleson et al, 2007).

A solution of 17% EDTA or citric acid as a final rinse (Byström and Sundqvist, 1985) is used to remove smear and has a positive benefit on outcome in retreatment cases (Ng, Mann and Gulabivala, 2011).

In this case the root canal had an immature morphology, and the terminal foramen was greater than a size 40 file.

There was no requirement to carry out mechanical instrumentation as the canal was already sufficiently large to allow adequate irrigant interchange. Instead, the irrigant was activated with an ultrasonic tip, which was lightly brushed against the walls and oscillated passively in the lumen of the canal with the hope of inducing acoustic microstreaming (Ahmad, Pitt Ford and Crum, 1987). The aim was to break up biofilm and remove contaminated surface layers of dentine.

Dressing the canals (after preparation and disinfection) with calcium hydroxide for seven days was shown to be effective at producing bacteria-free canals and so evolved the concept of a two-visit strategy using a chemomechanical approach (Byström, Claesson and Sundqvist, 1985; Sjögren et al, 1991).

More recently, universal use of a two-visit approach has been questioned. Peters and colleagues (2002) concluded that a calcium hydroxide and sterile saline slurry limits but does not totally prevent regrowth of endodontic bacteria. In a systematic review of the literature, Hargreaves reported that multiple visits with calcium hydroxide treatment did not improve upon clinical outcome and there was a minimal level of evidence for considering one versus two appointments in non-surgical endodontics (2006).

Indeed, a single visit approach is used by many endodontists for many cases with no apparent repercussions for the patient nor reduced prognosis (Ng, Mann and Gulabivala, 2011).

However, not all cases are ideally suited to a single visit approach and a two-visit strategy was adopted in this case to confirm resolution of the sinus tract before obturation and bleaching.

The immature root canal morphology can be challenging to obturate. Lateral condensation is difficult even with customised gutta percha points and excessive lateral pressure could potentially damage the thin root. Vertical compaction of gutta percha could result in extrusion of material unless a barrier or matrix is used at the terminal foramen. With the aid of an operating microscope the terminus of the canal can

often be visualised and controlled placement of materials such as MTA (Dentsply) or Biodenine (Septodont) can be achieved. Bioceramics such as these have excellent sealing abilities and have many reported uses in endodontics, including management of open apices (Parirokh and Torabinejad, 2010).

It was possible in this case to accurately place Biodentine without using a collagen matrix at the apex.

Tooth discolouration occurs as a result of the formation of chemically stable chromogenic products; these are oxidised during bleaching. Most discolourations can be reliably bleached apart from those that result from metal ions (Plotino et al, 2008).

Tooth whitening following root canal treatment can be carried out using an internal bleaching technique (walking technique) with materials such as sodium perborate, or carbamine peroxide sealed in the access cavity (Zimmerli, Jeger and Lussi, 2010) or via an internal/external approach with carbamine peroxide solutions (Poyser, Kelleher and Briggs, 2004). According to Carraso and colleagues, carbamide peroxide has been shown to have the best penetration into dentine (2003) and the walking technique a better outcome than in-office bleaching (Dietschi, Rossier and Krejci, 2006).

The internal/external technique requires the fabrication of bleaching trays and the access cavity can become contaminated with food particles and debris during use.

Endodontic bleaching has been cited as a possible cause of external cervical resorption (Heithersay, 1999), however, the etiology of this condition is not entirely clear. Defects in the cementum layer could potentially allow hydrogen peroxide from the pulp chamber to reach the external root surface and induce an inflammatory response (Rotstein, Torek and Misgav, 1991). Subsequent damage to the periodontium could therefore result in cervical resorption.

Avoiding placement of internal bleaching agents below the Cemento-Enamel Junction, checking for cervical lesions and not using heat, should prevent external cervical resorption (Patel, Kanagasinam and Pitt Ford, 2009).

After checking to make sure that there were no cervical defects, intermediate restorative material was placed over the gutta percha root filling material and at the cervical level of the root canal. Sodium perborate mixed with water is considered safer than hydrogen peroxide as an intracoronal bleaching agent and 35% carbamide peroxide (urea peroxide) combines the safety of sodium perborate together with the efficacy of 35% hydrogen peroxide (Lim, 2004).

In this case, an internal bleaching technique was used with a commercially available material: Endoperox (Septodont),

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a carbamine peroxide material.

The case was reviewed at three months and will continue to be reviewed at one year, two years and fours years post treatment (European Society of Endodontology, 2006) or until complete bony healing occurs.

Conclusion This case highlights the management and diagnosis of periapical periodontitis in a tooth that suffered dental trauma 11 years previously. Non-surgical microendodontic techniques were used to retreat the immature root morphology. No mechanical instrumentation was required and the immature root was sealed with Biodentine. Internal bleaching as a non-invasive means of restoring natural colour was demonstrated in this non-vital tooth.

References Ahmad M, Pitt Ford TJ, Crum LA (1987) Ultrasonic debridement of root canals: acoustic streaming and its possible role. Journal of Endodontics. 13, 490-499 American Association of Endodontists and American Academy of Oral and Maxillofacial Radiology Joint Position Statement (2011) Use of cone-beam computed tomography in endodontics. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology & Endodontology. 111, 234-37 Burleson A, Nusstein J, Reader A, Beck M (2007) The in vivo evaluation of hand / rotary / ultrasound instrumentation in necrotic human molars. Journal of Endodontics. 33, 782-87 Byström A, Claesson R, Sundqvist G (1985) The antibacterial effect of camphorated paramonochlorophenol, camphorated phenol and calcium hydroxide in the treatment of infected root canals. Endodontics and Dental Traumatology. 1,170-75.

Byström A, Sundqvist G (1981) Bacteriologic evaluation of the efficacy of mechanical root canal instrumentation in endodontic therapy. Scandinavian Journal Dental Research.

89, 321-8 Byström A, Sundqvist G (1983) Bacteriologic evaluation of the effect of 0.5 percent sodium hypochlorite in endodontic therapy. Oral Surgery Oral Medicine Oral Patholology. 55, 307-12 Byström A, Sundqvist G (1985) The antibacterial action of sodium hypochlorite and EDTA in 60 cases of endodontic therapy. International Endodontic Journal 18:35-40 Carraso LD, Froner IC, Corona SAM, Pecora JD (2003) Effect of internal bleaching agents on dentinal permeability of non-vital teeth: qualitative assessment. Dental

Traumatology. 19, 85-9 Diangelis AJ, Andreasen JO, Ebeleseder KA, Kenny DJ, Trope M, Sigurdsson A, Andersson L, Bourguignon C, Flores MT, Hicks ML, Lenzi AR, Malmgren B, Moule AJ, Pohl Y, Tsukiboshi M (2012) International Association of Dental Traumatology guidelines for the management of traumatic dental injuries: 1. Fractures and luxations of permanent teeth.

Dental Traumatology. 28, 66-71 Dietschi D, Rossier S, Krejci I (2006) In vitro colourimetric evaluation of the efficacy of various bleaching methods and products. Quintessence International. 37, 515-26 European Society of Endodontology (2006) Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. International Endodontic Journal. 39, 921–930 General Dental Council (2013) Standards for the Dental Team. [Online]. Available at: <http://bit.ly/1avam3q> [Accessed: March, 2015] Hannahan JP and Eleazer PD (2008) Comparison of success of implants Versus Endodontically Treated Teeth.

Journal Of Endodontics. 34, 1302–1305 Hargreaves KM (2006) Single-visit more effective than multiple-visit root canal treatment Evidence-Based Dentistry.

7, 13–14 Heithersay GS (1999) Invasive cervical resorption: an analysis of potential predisposing factors. Quintessence International. 30, 83-95 International Association of Dental Traumatology, Rigshospitalet Denmark (2010) The Dental Trauma Guide.

[Online]. Available at: <http://www.dentaltraumaguide.org>[Accessed March, 2015] Lim KC (2004) Considerations in intracoronal bleaching.

Australian Endodontic Journal. 30, 69-73 Ng YL, Mann V, Gulabivala K (2011) A prospective study of the factors affecting outcomes of nonsurgical root canal treatment: part 1: periapical health. International Endodontic Journal. 44, 583-609 Parirokh M, Torabinejad M (2010) Mineral Trioxide Aggregate: a comprehensive literature review – Part III: clinical applications, drawbacks, and mechanism of action.

Journal of Endodontics. 36, 400-13 Patel S, Kanagasingam S, Pitt Ford TR (2009) External Cervical Resorption: A Review. Journal of Endodontics. 35, 616-25 Pennington MW, Vernazza CR, Shackley P, Armstrong NT, Whitworth JM, Steele JG (2009) Evaluation of the costeffectiveness of root canal treatment using conventional

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approaches versus replacement with an implant. International Endodontic Journal. 42, 874-83 Peters LB, van Winkelhoff AJ, Buijs JF, Wesselink PR (2002) Effects of instrumentation, irrigation and dressing with calcium hydroxide on infection in pulpless teeth with periapical bone lesions. International Endodontic Journal. 35, 13-21 Plotino G, Buono g, Grande N M, Pameier CH (2008) Non-vital tooth bleaching a review of the literature and clinical procedures. Journal of Endodontics. 34, 394-407 Poyser NJ, Kelleher MG, Briggs PF (2004) Managing discoloured non-vital teeth: the inside / outside bleaching technique. Dental Update. 31 204-10, 213-14 Rotstein I, Torek Y, Misgav R (1991) Effect of cementum defects on radicular penetration of 30% hydrogen peroxide during intracoronal bleaching. Journal of Endodontics. 17, 230-3 SEDENTEXCT (2012) European Commission Radiation Protection No 172: Cone beam CT for dental and maxillofacial radiology (Evidence based guidelines).

[Online]. Available at: <www.sedentexct.eu/files/

guidelines_final.pdf> [Accessed March, 2015] Sjögren U, Figdor D, Spångberg L, Sundqvist G (1991) The antimicrobial effect of calcium hydroxide as a short-term intracanal dressing. International Endodontic Journal. 24, 119–25 Torabinejad M, Anderson P, Bader J Brown LJ, Chen LH, Goodacre CJ, Kattadiyil MT, Kutsenko D, Lozada J, Patel R, Petersen F, Puterman I, White SN (2007) Outcomes of root canal treatment and restoration, implant-supported single crowns, fixed partial dentures and extraction without replacement: a systematic review. Journal Prosthetic Dentistry.

98, 285-311 Van Nieuwenhuysen J-P, Aouar M, D’Hoore W (1994) Retreatment or radiographic monitoring in endodontics.

International Endodontic Journal. 27, 75-81 Zimmerli B, Jeger F, Lussi A (2010) Bleaching of Non-vital teeth. Schweiz Monatsschr Zahnmed. 120, 306-13 Reprinted with permission by ENDODONTIC PRACTICE May 2015

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The influence of aqueous and PEG 400 solvent vehicles on hydroxyl ion release from calcium hydroxide medicaments Yu-Yao Teoh,1 Basil Athanassiadis1,2 and Laurence J. Walsh1

Abstract Objectives: Calcium hydroxide pastes have been used in endodontics since 1947. Most current calcium hydroxide endodontic pastes use water as the vehicle, which limits the dissolution of calcium hydroxide which can be achieved and thereby the maximal hydroxyl ion release which can be achieved within the root canal system. Methods and Materials: This study compared the ionic properties of calcium hydroxide solutions in water or polyethylene glycol (PEG), then the ionic properties of commercial endodontic medicaments made using water or PEG, and finally hydroxyl ion release into radicular dentine in vitro using a new model with colour change in anthocyanin stained roots. Results: PEG 400 as a solvent gave a higher pH and more bio-available hydroxyl ions than water. Commercial pastes made using PEG 400 as the solvent showed a greater pH than those formulated with aqueous vehicles (water or saline).

Hydroxyl ion penetration into roots under physiological conditions was greater when PEG was used as the medicament base than mixtures of PEG and water. Clinical significance: Enhanced availability and release of hydroxyl ions will enhance antimicrobial actions of calcium hydroxide when it is the active agent in endodontic medicaments.

Keywords: Calcium hydroxide, PEG 400, non-aqueous solvents, pH Short Title: pH of calcium hydroxide medicaments

Introduction

The University of Queensland, Brisbane, Australia

1

Private Dental Practice, Brisbane, Australia

2

Corresponding author: Professor Laurence J. Walsh The University of Queensland School of Dentistry UQ Oral Health Centre, 288 Herston Road, Herston QLD 4006 Australia E: l.walsh@uq.edu.au T: + 61-7-33658160 F: + 61-7- 33658199

Hydroxyl ion release from calcium hydroxide is responsible for the key attributes of broad spectrum antimicrobial activity, penetration into biofilms, inhibition of endotoxins, and dissolution of organic tissues.1,2 The maximum solubility of calcium hydroxide in water at 25OC is only 0.159 g/100mL (0.16%), and this reduces to 0.140 g/100 mL (0.14%) at 40OC, with an accompanying decrease of 0.033 pH unit/OC with increasing temperature.3 Calcium hydroxide is much less soluble in water than sodium hydroxide or potassium hydroxide, however both the latter too caustic to soft tissues for clinical use.4 To gain the greatest antimicrobial actions, release of hydroxyl ions from endodontic pastes must be optimized. Traditional water-based calcium hydroxide pastes have a long history of clinical use, with PulpdentTM paste (Pulpdent Corporation, Watertown, Massachusetts, USA) having been on the market since 1947. In products with a waterbased vehicle (e.g. distilled water or saline), the common ion effect operates, since water already contains some free hydroxyl ions. Most calcium hydroxide endodontic pastes which are water-based calcium hydroxide contain a large excess of calcium hydroxide, well beyond that which can be dissolved.2 Placing calcium hydroxide into water in amounts above the solubility limit will not elevate the pH which can be achieved, since no further material can dissolve. The undissolved material will act as a filler or thickener in the paste, and as hydroxyl ions diffuse into the surrounding environment, it can also act as a reservoir.

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Table 1. Relationships between ion concentrations, pH, pOH and millivoltage pH

H+ concentration (mol/l)

pOH

OHconcentration (mol/l)

mV

0

1

14

1x10-14

+414.12

1

0.1

13

1x10-13

+354.96

10

-10

+177.48

-4

4

1x10

7

1x 10-7

9

-9

1x10

7

1x 10-7

1x 10

5

-5

1x 10

-118.32

12

1x 10-12

2

0.01

-295.80

14

-14

0

1

-414.12

1x 10

0

Mathematical relationships seen in pure water at 25oC between pH, pOH, hydroxyl ion concentrations and millivoltage recordings for conventional pH electrodes with KCl electrolyte.

There is a long history of the use of non-aqueous liquids in endodontic pastes, going back to the mid-1970â&#x20AC;&#x2122;s when components such as polyethylene glycol (PEG) 400 were added to alter the viscosity to improve the clinical handling of the paste. As an example, the 1976 formulation of a calcium hydroxide paste (Calen) included both PEG 400 and colophony resin, with the latter being a thickening agent. Other viscosity modifiers used in calcium hydroxide pastes have included glycerol and propylene glycol.1 It is now recognised that such non-aqueous liquids are not merely passive agents, but may actively contribute to the chemical and biological properties of the paste, by enhancing dissolution of calcium hydroxide and release of hydroxyl ions. PEG 400 is used in contemporary endodontic pastes which contain calcium hydroxide, calcium hydroxide plus ibuprofen, or antibiotics and corticosteroids.

The aim of the present study was therefore to assess the chemical properties of PEG 400 when used as a nonaqueous solvent for calcium hydroxide, with a particular emphasis on the release of hydroxyl ions. Such release can be considered in terms of the pOH and pH scales. While originally theorized by Sorensen for water-based solutions, it is now well known that the pH scale can also be used as a measure of the acid-base properties of non-aqueous solutions.5,6 This is done typically using research-grade pH meters that display both pH (from -2.00 to +20.00) and millivolts, and which are fitted with either conventional electrodes or electrodes specifically designed for the

measurement of non - aqueous solutions, using reference electrolytes such as lithium chloride 2 mol/l in ethanol or tetraethylammonium bromide (TEABr) 0.4 mol/l in ethylene glycol), for acidic and alkaline materials, respectively. Using such meters and electrodes, assessments of hydroxyl ion concentration (pOH) and pH can be made for aqueous and non-aqueous materials. There are mathematical relationships between pOH, pH and millivoltage (Table 1). When considering the ionic properties of non-aqueous solvents, one has to consider dissociation of the solvent and the slower response time of non-aqueous electrodes, which require extended measurement times. Thus, the first part of the study assessed ionic properties of calcium hydroxide in different solvents, the second the ionic properties of calcium hydroxide medicaments with different compositions, and the third the diffusion of hydroxyl ions into roots of extracted teeth.

Materials and Methods Part 1. Ionic properties of solutions A research grade pH meter (model HI 4222, Hanna Instruments, Woodsocket, Rhode Island, USA) was used for all measurements. The meter was calibrated using four standard aqueous buffers at pH values of 4, 7, 10, and 13 (ACR Chemical Reagents, Moorooka, Queensland, Australia). Two different electrodes were used to measure the pH in medicaments and different calcium hydroxide/PEG 400 mixtures, the first being a conventional electrode (model IJ-44C, Ionode, Tennyson, Queensland, Australia), while the

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Table 2. Components of commercial calcium hydroxide pastes Pulpdent

Calasept Plus

CalMix

Odontocide

Active ingredients

39-42% Ca(OH)2

41.07 % Ca(OH)2

37.5% Ca(OH)2

20% Ca(OH)2 7% Ibuprofen

Vehicle

Water

Isotonic saline

45.5% PEG 400

61% PEG 400 5% Water

Thickener

Methyl cellulose

Nil

PEG 4000

2.3% PEG 3000

Radiopaque agent

Barium sulphate

8.33% Barium sulphate

14% Zirconium dioxide

2% Barium sulphate

Components are shown in percentages by weight. Information on product composition was obtained from material safety data sheets and manufacturer websites.

second was designed specifically for non- aqueous solvents (Solvotrode, Metrohm Instruments, Gladesville, NSW, Australia), and contained 2% lithium chloride in ethanol as the reference electrolyte. As instructed by the latter electrode manufacturer, for testing alkaline materials the lithium chloride in ethanol electrolyte was removed and replaced with a solution of TEABr in ethylene glycol prior to use. When the electrodes were not in use they were stored in their recommended storage solutions (2% KCl in water for the Ionode electrode, and TEABr in ethylene glycol for the Solvotrode electrode).

The pH of various concentrations of calcium hydroxide (analytical grade, Chem-Supply, Gillman, South Australia, Australia) placed in ultrapure water or polyethylene glycol 400 (Ace Chemical Company, Camden Park, South Australia, Australia) was measured, at final concentrations of 5%, 10%, 20% and 40%. Calcium hydroxide powder was added to PEG 400 in disposable plastic clear tubes 15 mm diameter and 95 mm high, and mixed vigorously using a metal spatula for 20 seconds to achieve a uniform mix. The Solvotrode electrode was inserted into this mixture and the pH recorded at room temperature (23OC) every 5 minutes until a stable measurement was reached.

The pH values of five separate samples for each of the different concentration of calcium hydroxide/PEG 400 mixtures were recorded. For all pH measurements, values were tracked over time until they became consistent. For the different mixtures of calcium hydroxide in PEG 400, between 60 and 140 minutes was required before a stable value was reached. Recorded values for pH from five independent

experiments were assessed for normality, and then differences analyzed using Studentâ&#x20AC;&#x2122;s t test, or analysis of variance with Bonferroni post-tests. Data sets met requirements for parametric statistical comparisons.

Part 2. Ionic properties of medicaments The pH of four commercial calcium hydroxide medicaments was measured. Two of the commercial medicaments were water based (PulpdentTM paste, Pulpdent Corporation, Watertown, Massachusetts, USA, and Calasept PlusTM, Nordiska Dental, Angelholm, Sweden) and two used PEG 400 as their base (OdontocideTM, Australian Dental Manufacturing, Kenmore Hills, Queensland, Australia, and CalmixTM, Ozdent, Castle Hill, NSW, Australia). The composition of these medicaments is given in Table 2.

For the two PEG 400-based commercial medicaments (Calmix, Odontocide) between 60 and 140 minutes was required before a stable value was reached, whilst the water based medicaments (Pulpdent, Calasept plus) took only 10 minutes to reach a stable pH value. For Pulpdent and Calasept Plus (aqueous solvent), between measurements the electrode was washed by vigorous stirring in three separate lots of distilled water for 2 minutes each to remove any paste on the electrode, and to reduce the final pH registered on the electrode to approximately pH 7, to ensure a neutral reading at the electrode tip prior to further readings. For Calmix and Odontocide (PEG solvent), the same regimen was followed, but the electrodes were then placed in their relevant storage solutions for a minimum period of five minutes to replenish the electrode tip after which it was washed in distilled water.

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Part 3. Hydroxyl ion release into radicular dentine The experimental model involved tracking changes in the colour of anthocyanin dye in stained roots kept at physiological conditions. Anthocyanin is the pH indicator found in red cabbage, and it undergoes multiple colour changes with pH over the alkaline range, with corresponding increases in both the red and green channels as the colour changes. A series of buffers from pH 8.0 to 13.0 were prepared to serve as a reference for changes in pixel data (Fig. 1). Extracted human permanent teeth were collected from an oral surgery clinic with the approval of the institutional ethics committee. A total of 15 single-canal teeth free from intrinsic discolouration or translucency were selected, then the crowns removed at the cemento-enamel junction and the root face smoothened to form a flat coronal surface using abrasive discs. After patency of root canals was confirmed using a #8 K-file (Dentsply Maillefer, Switzerland), they were then prepared with NiTi rotary instruments (ProTaper Next, Dentsply Maillefer, Switzerland) to size X3 with variable taper and an apical preparation of ISO #30. The root canals were irrigated alternately with sodium hypochlorite and ethylenediaminetetraacetic acid (EDTA) using syringes with side-vented needles. After a final irrigation step using EDTA for 2 minutes, the canals were dried with paper points, and the roots placed in saline at room temperature for 24 hours to neutralise any remnants of sodium hypochlorite.

To stain the roots, a 3% solution of anthocyanin (Red Cabbage Jiffy Juice™ powder) in water was prepared. The prepared roots were removed from the saline bath and dried with paper towels and paper points, and the canals then irrigated with dye solution before submerging the roots into the dye for 48 hours. This achieved a uniform purple stain throughout the root. The stained roots were dried with paper towels and mounted upright using sticky wax onto a holder so that the coronal surface of the root could be photographed using a digital camera under fixed conditions (constant lighting, distance and exposure settings) together with a colour reference card and a calibration ruler, to obtain a baseline image as a reference point from which subsequent changes could be measured. The roots were assigned randomly assigned to 5 groups of 3 each. One served as an untreated control in which no medicament was placed. The four treatment groups were PEG 400 as a vehicle control, 20% calcium hydroxide in PEG 400, Odontocide and Calmix. The materials were injected into the root canal under positive pressure until excess was seen to extrude apically. After removing excess material on the

Figure 1: Colour changes in anthocyanin dye according to pH, using a series of buffers with pH values from 8 to 13. The upper panel (A) shows the visual appearance of a solution of anthocyanin dye as pH alters. Each vial has the same concentration of dye. The lower panel (B) shows the digital pixel data for red and green channels for the pH standards. There is a consistent increase in both parameters as the pH rises.

coronal and outer surface of each root, the apex was sealed with molten wax, and each root then placed into an individual Eppendorf tube which was filled with anthocyanin dye solution to a level just below the coronal surface of the tooth. The samples were then maintained at 37˚C in an incubator for 3 weeks.

Digital photographs of the coronal surface of the roots were taken after 1, 2, 3, 5, 7, 14, and 21 days. Image analysis was undertaken using Adobe Photoshop™ CS6 Extended software to track changes in each root over time, and calculate the colour change in red and green channels from the baseline using a repeated measures assessment. The selected area of interest was located 500 microns from the root canal walls, as this was considered the greatest depth into the tubules that microorganisms would likely be found.

The selected area (10 X 10 pixels) was identical on sequential images of each root. Pixel information was

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Table 3. The pH of calcium hydroxide in PEG 400 Ca(OH)2 concentration Ionode electrode Solvotrode electrode

5%

10%

20 %

40%

12.918 d (0.115)

13.344 c (0.117)

13.938 b (0.066)

14.75 a (0.089)

13.260 d (0.083)

13.598 c (0.063)

14.298 b (0.078)

14.940 a (0.118)

Data show the mean and SD from five independent experiments. Letters indicate statistical groupings across each row, ranked from highest pH (a) to lowest pH (d).

collected using the histogram tool, which gave red and green values for the selected area on a scale with 256 points. The extent of change from baseline was calculated for the three replicates for each group, and analysed using GraphPad Prismâ&#x201E;˘ software applying non-parametric analyses for repeated samples as well as intra-group comparisons.

Results Ionic properties of solutions When the pH of 5%, 10%, 20% and 40% solutions of calcium hydroxide in water or PEG400 was measured every 5 minutes for 2 hours using both a conventional electrode with KCl electrolyte (Ionode), and an electrode designed specifically for alkaline non- aqueous solvents (Solvotrode) containing TEABr in ethylene glycol, PEG 400 as a solvent for calcium hydroxide gave a higher pH than water. Water solutions gave pH values which reached a plateau at 12.7.

For solutions of calcium hydroxide in PEG 400, the pH increased with the concentration of calcium hydroxide, and there was a significant positive association with concentration (P<0.001) (Table 3). With the Ionode electrode, the pH differential between 5% and 40% mixtures was 1.87, and 1.74 with the Solvotrode electrode.

Differences in the readings between the two electrodes were consistent, and were statistically significant at each concentration (P<0.02). The Solvotrode electrode recorded higher pH values by 0.19-0.36 pH units for all mixtures. The non-aqueous electrode consistently recorded significantly higher pH values by 0.19-0.36 pH units for all mixtures and medicaments (P<0.02). pH increased by 1.74-1.87 pH units between the 5% and 40% calcium hydroxide mixtures in PEG 400 (P<0.001) with the KCl and TEABr electrodes respectively.

Ionic properties of medicaments Medicaments based on PEG400 had a more alkaline pH (Table 4). Differences in the readings between the two electrodes were consistent, with the TEABr electrode always being higher by 0.05-0.16 pH units. The ranking of medicaments from most alkaline to least alkaline was Calmix, Odontocide, Pulpdent and then Calasept Plus, with both electrodes. Measured pH differences between materials were statistically significant (P<0.001). With the Ionode electrode, all measured pH differences between materials were statistically significant (P<0.001), except for Pulpdent versus Calasept Plus. In contrast, with the Solvotrode electrode, all differences between Calmix and other materials were statistically significant (P<0.001), but there was no significant difference between the other three pastes.

Differences in the readings between the two electrodes were consistent, with the Solvotrode electrode always being higher by 0.05-0.16 pH units. Differences in the readings between the two electrodes were statistically significant for all materials (P<0.04) other than for Odontocide, where the trend was the same (P=0.6065).

The measured pH values for Odontocide, which contains 20% calcium hydroxide in PEG 400 as well as ibuprofen, were not significantly different from those of the 5% calcium hydroxide in PEG 400 mixture. In contrast, the pH values for Calmix, which contains 37.5% calcium hydroxide in PEG 400, were significantly higher than those obtained for 40% calcium hydroxide in PEG 400 (P<0.05).

Hydroxyl ion release into roots Tracking the extent of colour change over 3 weeks in the stained roots revealed that there were no changes in untreated roots with open canals or in canals treated with

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PEG 400 only (Fig. 2). There were obvious changes in the stained roots over the 3 week period of the experiment, with the characteristic change from a deep purple-blue baseline colour to a yellow colour for the dentine adjacent to the root canal. From gross observation, such changes were most apparent with Calmix (Fig. 3). Quantitative analysis of changes in colour revealed positive changes in both green and red pixel data at 500 microns from the canal wall with each of the three calcium hydroxide materials, indicating that elevations in the pH of the root dentine had occurred progressively over the first 7 days and had then begun to stabilize. The groups were ranked in terms of greatest change to least as Calmix > Odontocide > 20% calcium hydroxide in PEG. Differences between treatments were statistically significant at 7 days and beyond for green and red channel data, with Calmix superior to other groups. After 7 days, the colour change continued to rise slowly for Calmix but began to decline for Odontocide, indicative of buffering of hydroxyl ions by dentine.

Discussion The results of this study provide several insights into the behaviour of calcium hydroxide in different solvents. The results of the first part of the study showed that compared to water, polyethylene glycol 400 when used as a solvent allows high pH values to be achieved, which are above

pH 12.4, the nominal limit for aqueous pastes. While PEG 400 was first used as a viscosity modifier in the endodontic paste Calen in the 1970’s, its ability to alter hydroxyl ion release is a novel finding. The present results indicate that PEG 400 is a suitable solvent for calcium hydroxide.

Chemically, this is due to the large number of ethylene oxide groups along its backbone, which allows PEG to form complexes with metal cations, including calcium ions.7 Such binding of calcium ions drives the dissociation of calcium hydroxide, thus releasing more free hydroxyl ions. This notion is supported by the quantitative results of the root dentine experiment, which showed greater levels of available ions at the same location in the dentine.

PEG 400 is a colourless water soluble and hygroscopic polymer that is miscible with water in all proportions, which explains why PEG 400 can be used as a solvent in its own right with or without the addition of water. PEG is classified as “Generally Recognized as Safe” and has high biocompatibility.7 It has a suitable viscosity for delivery through a fine tip. When used without any added water, as in the case of Calmix, the material will not dry out over time.

Calcium hydroxide pastes produce a high alkaline pH when measured directly with pH electrodes, as shown in the second part of this study, but under clinical conditions the released hydroxyl ions have to diffuse throughout the dentine, during which some buffering will occur from both inorganic and organic components. A saturated aqueous solution of

Table 4. The pH of commercial endodontic pastes measured using two different electrodes Pulpdent

Calasept Plus

Odontocide

Calmix

Ionode

12.706 c

12.662 c

13.170 b

14.996 a

electrode

(0.006)

(0.017)

(0.025)

(0.010)

Solvotrode

12.862 b

12.710 b

13.062 b

15.162 a

electrode

(0.008)

(0.012)

(0.450)

(0.108)

pH value

> 12.0

12.4

12.5

>13.5

stated by manufacturer Data show the mean and SD from five independent experiments. Letters indicate statistical groupings across each row, ranked from highest pH (a) to lowest pH (c). Information on product pH stated by the manufacturer was obtained from material safety data sheets and manufacturer websites.

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Figure 2: Quantitative assessment of changes from baseline in pixel data for the red (upper) and green (lower) channels for a sample area located 500 microns from the canal wall in the radicular dentine. The effects of two pastes containing PEG 400 (Calmix in green and Odontocide in red) are compared to 20% calcium hydroxide in PEG (grey). PEG 400 alone (purple) and an empty canal (black). Data are the mean of three independent experiments.

Figure 3: Typical examples of anthocyanin-stained roots showing colour changes due to hydroxyl ion release from medicaments over time, with the colour shifting from purple-blue to green and then yellow as pH rises from the canal walls through the dentine.

calcium hydroxide is easily buffered by dentine8 as has been seen when dentine powder is added to saturated calcium hydroxide solutions. This emphasizes the rationale behind third part of the study, which measured alkalinizing effects in radicular dentine using anthocynanin dye. This dye was chosen because colour changes correspond to pH changes in a predictable manner giving a gradual change between colours, from purple-blue to green and then to yellow as pH increases into the highly alkaline range.

The antimicrobial activity of calcium hydroxide is based

on effective release of hydroxide ions, which destroy phospholipids of microbial cell membranes as well as bacterial DNA 9,10. It is therefore important that hydroxide ions penetrate into the dentine of the root in sufficient concentration to overwhelm the buffering effects of dentine and cause a highly alkaline pH environment to be sustained both within the root canal system and the adjacent dentine, in order to suppress growth of microorganisms, particularly resistant species such as Enterococcus faecalis, which are able to survive and form biofilms in a pH 10 environment. E.

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faecalis is however inactivated by alkaline environments at pH values around 11.5 to 11.9 11,12. The rationale for using a non-water solvent such as PEG 400 is to help achieve a sufficiently high pH at the canal walls and into the inner radicular dentine to reach this objective.

Conclusions While the concepts of ionic equilibria and pH in nonaqueous solvents have been well documented in the literature for many years 13, the chemical properties of such materials as vehicles for calcium hydroxide in dentistry has not hitherto been explored. This study has shown that PEG 400 is a suitable vehicle for calcium hydroxide, and gives higher pH values than can be achieved in aqueous solutions.

Commercial medicaments which use PEG without water show higher measured pH and greater pH change in radicular dentine than those which contain PEG mixed with water, or water alone. The results of the present study also show the potential of anthocyanin staining as a method which can show pH fluctuations in root dentine caused by endodontic medicaments. Such experimental approaches may be useful to inform the development of products which can achieve the desired pH changes in the inner dentine for effective disinfection.

Conflict of interest statement Two of the authors (BA and LW) are co-inventors of Calmix paste.

References 1. Fava LR, Saunders WP. Calcium hydroxide pastes: classification and clinical indications. Int Endod J. 1999;32(4):257-82.

2. Athanassiadis B, Abbott PV, Walsh LJ. The use of calcium hydroxide, antibiotics and biocides as antimicrobial medicaments in endodontics. Aust Dent J. 2007;52(1

Suppl):S64-82.

3. Bates RG, Bower VE, Smith ER. Calcium hydroxide as a highly alkaline pH standard. J Res Nat Bureau Stds 1956;56(6):305-12.

4. Sweetman S (ed). Martindale: the complete drug reference. 36th edition. London: Pharmaceutical Press, 2009: p. 2272.

5. Tremillon B. Chemistry in non-aqueous solvents.

Netherlands: Springer, 1974.

6. Quitmeyer J. pH Measurement in aqueous and nonaqueous solutions: When used in combination with titration, pH measurement is a simple method to monitor bath concentration. Metal Finishing 2008:106(10):21-24.

7. Chen J, Spear SK, Huddleston JG, Rogers RD. Polyethylene glycol and solutions of polyethylene glycol as green reaction media. Green Chem 2005;&:64-82.

8. Athanassiadis B, Abbott PV, George N, Walsh LJ. An vitro study of the inactivation by dentine of some endodontic medicaments and their bases. Aust Dent J. 2010;55(3):298305.

9. Freeman BA, Crapo JD. Biology of disease: free radicals and tissue injury. Lab Invest 1982; 47:412-26.

10. Ran S, Liu B, Jiang W, Sun Z, Liang J. Transcriptome analysis of Enterococcus faecalis in response to alkaline stress. Front Microbiol. 2015;6 (795):1-11.

11. Flahaut S, Hartke A, Giard JC, Auffray Y. Alkaline stress response in Enterococcus faecalis: adaptation, crossprotection, and changes in protein synthesis. Appl Environ Microbiol 1997;63:812-4.

12. Evans M, Davies JK, Sundqvist G, Figdor D. Mechanisms involved in the resistance of Enterococcus faecalis to calcium hydroxide. Int Endod J 2002; 35:221-8.

13. Roses M. Ionic equilibria in non-aqueous solvents Part 1. General equations for calculation of pH, dissociation constants and reference potentials from potentiometric data.

Anal Chim Acta 1993;276:211-21.

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CLINICAL

Making sense of mouth ulceration: Drug-induced ulceration Crispian Scully1

Drug-induced ulceration A range of drugs can cause oral ulceration (Table 1), so it is therefore important for the clinician to take a comprehensive drug history and always consider whether a drug may be behind the problem.

Clinically, there is rarely any particular feature (Figure 1). The diagnosis is from the history and by exclusion. A high index of suspicion is needed. Management is by avoiding the offending drug.

Mucositis

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.

Chemotherapy (CTX) often causes acute injury to mucosae, affecting the mouth and whole gastrointestinal tract. CTX activates inflammatory pathways (such as the NF-kB pathway) and release cytokines, such as TNF-alpha, IL-1 and IL-6.

Most patients on high-dose CTX develop severe oral mucositis within a week of starting treatment, especially with CTX using: • Cisplatin • Etoposide • Melphalan.

It can also be an issue with other CTX, especially anthracyclines (bleomycin, dactinomycin, daunorubicin, doxorubicin, epirubicin, idarubicin, mitomycin, mitoxantrone), antimetabolites (cytarabine, fluorouracil, floxuridine, methotrexate, thioguanine) and antimitotic agents (taxanes such as docetaxel and paclitaxel; vinca alkaloids such as vinblastine and vindesine).

Clinical features of mucositis are widespread erythema, erosions/ulceration, swelling, and atrophy.

Diagnosis is from the history. Lesions in the cancer patient that can complicate the diagnosis of mucositis include fungal and viral infections as well as neutropenic ulcers.

Management is crucial since many patients find oral mucositis the most debilitating and troublesome adverse effect of cancer therapy. In addition, some find that although opioid analgesics are needed, they do not always adequately relieve pain, and can lead to other issues such as dry mouth and constipation.

There are few randomised controlled studies, and the available prophylactic and therapeutic strategies are limited, but discomfort from mucositis can be further reduced by: • Excellent oral hygiene • Oral cryotherapy using ice popsicles • Exposure to soft laser • Systemic administration of keratinocyte growth factor (palifermin).

Emergent agents being trialled for amelioration of the suffering of mucositis include buprenorphine transdermal patches for analgesia.

Graft-versus-host disease Graft-versus-host disease (GVHD) may be a complication of bone marrow transplant or haematopoietic stem cell transplant (HSCT). This transfers T lymphocytes that perceive host tissues as antigenically foreign via HLA and other antigens, and mount an immune attack on the host, the transferred T-cells producing cytokines, including TNK-alpha and IFNγ.

Acute GVHD appears between 10 and 100 days post-transplant, is seen in about 60% of transplant survivors and may cause mouth ulceration. Acute GVHD affects

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*Prices may vary if the book is purchased in New Zealand

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CLINICAL

Table 1: drugs implicated in oral ulceration Alendronate Anticonvulsants Biologic agents (mainly anti-TNFs) Cytotoxic agents Everolimus (and mTOR inhibitors) Mycophenolate Nicorandil NSAIDs Tiotropium Others (many) Figure 1: Drug-induced ulcer

mainly the liver, gastrointestinal tract and mucocutaneous tissues, and can be lethal. Therefore, prophylactic immunosuppressive therapy using methotrexate and ciclosporin is usually used for the first 100 days post-HSCT. The oral manifestations of acute GVHD are difficult (or impossible) to differentiate from chemotherapy-induced mucositis. Acute GVHD is treated with high-dose immunosuppressive therapy.

Chronic GVHD may follow acute GVHD, or may arise ab initio, occurs after 100 days post-HSCT and affects around 50% of patients. Chronic GVHD can cause mouth ulcers and involves multiple organs – mainly the liver, gastrointestinal tract, eyes and skin.

In most cases (80%), oral lesions appear, including: • Ulceration • Lichenoid lesions • Infections, especially candidosis • Hairy leukoplakia • Sclerodermatous syndrome and hyposalivation • Ciclosporin-induced gingival swelling.

Chronic GVHD is treated with high-dose immunosuppressive therapy.

Management of orofacial lesions in acute or chronic GVHD is mainly with: • Analgesics (morphine, buprenorphine or hydromorphone) • Oral hygiene measures, including non-alcoholic chlorhexidine mouth rinses • Artificial saliva (mouth wetting agents), xylitol chewing gum or pilocarpine • Topical azathioprine or ciclosporin • Nystatin or fluconazole suspension • Growth factors.

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. Wiley-Blackwell (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

Disclosure This series offers a brief synopsis of the diagnosis and management of mouth ulceration – a complex topic that includes common disorders, and less common but lifethreatening conditions. It does not purport to be comprehensive, and the series may include some illustrations from books written or co-authored by the author and colleagues from UK and overseas, published by Elsevier-Churchill Livingstone, WileyBlackwell, or Informa/Taylor & Francis – all of whose cooperation is acknowledged and appreciated.

Published with permission by Private Dentistry December 2014

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SCHEU

CALMIX

LC-6 LIGHT OVEN

Calmix is the most recent innovation in calcium hydroxide pastes, providing superior hydroxyl ion release and greater antimicrobial activity than existing calcium hydroxide pastes. It employs a patented non-water solvent which gives superior effectiveness for hydroxyl ion release as well as better flow and handling characteristics. Calmix is more radiopaque than other current calcium hydroxide pastes making it easier to identify on radiographs, and it can easily be delivered directly into the root canal through the special tips provided. It is easy to remove from the canal by irrigation when later stages of endodontic treatment are needed.

High-capacity light polymerisation unit for up to four models or fixator, offering enough space for articulated or mounted models. Six fluorescent light tubes (three UVA and three blue light tubes) and an aluminium reflector guarantee homogeneous illumination.

Two polymerisation times of 5 and 10 minutes are already pre-set in accordance with the light-curing material DURASPLINT® LC. Continuous operation can also be set. Auto start function for easier application.

QUINTESSENCE

CLINICAL PHOTOGRAPHY IN DENTISTRY: A NEW PERSPECTIVE Peter Sheridan The primary aim of this seminal book is to make the case that digital photography is an essential instrument for evidence and interaction in dental practice. Unlike many books on this subject, this book redefines the scope of and rationale for clinical photography beyond the obvious focal point of anterior teeth and aesthetics to include all oral tissues and the entire spectrum of dental care. In addition, the author outlines the most suitable camera equipment and accessories, the correct technique

and positioning, and the protocol for digital image management to ensure high-quality images. This book will help dentists appreciate the value and scope of digital photography in general dentistry and allow them to seamlessly incorporate the equipment and techniques into their clinical practice and workflow. An essential book that expands the place of clinical photography and underscores its role in improving clinical records and communication.

Q-5120822 232 pp; 554 illus

All products available from: HENRY SCHEIN HALAS • Tel: 1300 65 88 22 • www.henryschein.com.au 62 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION VOL. 11, NO. 4

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PRODUCTS

QUINTESSENCE

KURARAY NORITAKE

FUNDAMENTALS OF IMPLANT DENTISTRY, VOLUME II: SURGICAL PRINCIPLES

PANAVIA V5

New Panavia V5 – One simple & esthetic cement for all your needs PANAVIA™ V5 is a true dual-cure, fluoride-releasing, colur stable, esthetic radiopaque, universal resin cement with simplified placement & easy clean – up technique. PANAVIA™ V5 also provides adhesive milestone by providing self-cure dentin bond strengths equal to a “Gold Standard” light- cure bonding agent, CLEARFIL SE BOND. PANAVIA V5 “Versatile” Simplified Procedure, Improved Esthetics and increased Adhesion.

• High bond performance with optimal esthetics • Kuraray Noritake’s original MDP formulation for unsurpassed adhesion • Simple, fast application with effortless clean-up • Wide indication range • Excellent colour stability, 5 shades • Low solubility and low film thickness • Natural fluorescence • High mechanical strength in both self-cure and light-cure modes

Peter K. Moy, Alessandro Pozzi & John Beumer III Since the concept of osseointegration was introduced to the dental community more than 35 years ago by Professor P-I Brånemark, significant improvements have been achieved in patient evaluation, methods used to enhance the bone and soft tissues of potential implant sites, and surgical techniques to prepare the osteotomy sites and place the implants. These topics are thoroughly discussed from the perspective that an interdisciplinary approach will yield the most predictable outcomes for treatment of the dental implant patient. The authors address the sometimes controversial topic of immediate loading and provide useful insights regarding when this approach can achieve predictable outcomes and when it is to be avoided. The use of CAD/CAM technologies is emphasized throughout the text, and the latest developments and their use in this rapidly expanding arena are fully described.

Q-5120820 448 pp; 1,300 illus

PHILIPS

ULTRADENT

ROSE GOLD DIAMONDCLEAN

VALO GRAND CURING LIGHT

A toothbrush that makes you feel glamorous The new Philips Sonicare DiamondClean RoseGold Edition makes you stand out from the crowd. With its award-winning design it’s a toothbrush that makes you feel special. It improves your gum health and gives you whiter teeth for life.

ALL of the benefits of the revolutionary, award-winning Valo® with a 50% bigger lens When it comes to curing, the circumstances aren’t always ideal.

Squirming patients, sectional bands blocking the light from getting to the entire restoration, even a simple hand movement can prevent a complete cure. That’s where the VALO Grand curing light comes in.

The VALO Grand light has a large 12 mm lens that allows you to cover more area in a single cure. With the VALO Grand light, you won’t miss a thing.

All products available from: HENRY SCHEIN HALAS • Tel: 1300 65 88 22 • www.henryschein.com.au

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