International Dentistry

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VOL. 1 2 NO. 4 IN THIS ISSUE Tihanna Milic and Laurence J. Walsh The practical application of protective stainless steel bands and wedges for prevention of iatrogenic damage during Class II cavity preparations Richard Price Consensus statements on bulk fill resin composites Urs Belser, German Gallucci, Kelvin Afrashtehbar and Daniel Buser Prosthetically driven techniques to compensate peri-implant soft tissue deficiencies Cyril Gaillard and Jérôme Bellamy From digital planning to the mock-up and final restoration Tihana Milic, Megan Valentine, Sowmya Shetty and Laurence J. Walsh Analysis of dental clinicians’ ability to detect iatrogenic damage, and the possibility of using a low viscosity nano-filled resin to protect damaged surfaces Panel discussion with Howard Strassler, Joe Oxman and Frederick Rueggeberg What should you look for in a curing light?

A Congolese Dental School Creating change six students at a time

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4

Contents Volume 12 No. 4

4

Research

12

Clinical

18

Clinical

36

Clinical

42

Research

50

Clinical

56

A Congolese Dental School

The practical application of protective stainless steel bands and wedges for prevention of iatrogenic damage during Class II cavity preparations Tihanna Milic and Laurence J. Walsh

12

18

36

Consensus statements on bulk fill resin composites Richard Price

Prosthetically driven techniques to compensate peri-implant soft tissue deficiencies Urs Belser, German Gallucci, Kelvin Afrashtehbar and Daniel Buser

From digital planning to the mock-up and final restoration Cyril Gaillard and Jérôme Bellamy

Analysis of dental clinicians’ ability to detect iatrogenic damage, and the possibility of using a low viscosity nano-filled resin to protect damaged surfaces Tihana Milic, Megan Valentine, Sowmya Shetty and Laurence J. Walsh

What should you look for in a curing light?

A panel discussion with Howard Strassler, Joe Oxman and Frederick Rueggeberg

Creating change six students at a time

58 Products

VOL. 12, NO. 4 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION 1

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Henry Schein Halas Perth moves to a new home

Vol. 12 No. 4 ISSN 2071-7962 PUBLISHING EDITOR

Over the last couple of years, Henry Schein Halas has been gradually updating all of their facilities to ensure their offering to the market is as up to date as possible in each state. The Perth office is the latest to make the move following Adelaide, Melbourne and Brisbane.

The new office was officially opened in October 2017 by Managing Director, Mike Covey, and Branch Manager, Gayle Jones, and was well attended by local members of the dental community.

You will now find the company at 195 Great Eastern Hwy, Belmont.

This brand new facility not only has a modern and inviting showroom, but training facilities that will be well utilised with Henry Schein Halas’s growing CPD programs. Designed with multi-purpose functionality, the room can be used for display, hands-on training and houses the latest dental technology available on the market.

The training space seats up to 50 participants. It has been fitted with modern audio-visual equipment for professional presentations and training, as well as multi-functional furniture to ensure the set up can be customised to the programs’ specific needs.

So far, the showroom has been introduced to various customers, but there are many more plans for its use in the future. “I am so proud to be working in an environment where customers can really see the products and how they will fit into their personal surgeries prior to purchase” said Gayle Jones. “It’s important for them to understand what will best suit their needs” she said. Prior to the opening, dentists would need to travel to a tradeshow if they wanted to view multiple pieces of equipment that were fully functioning. Henry Schein Halas now has this on display at all times and anyone looking to upgrade can make an appointment at their convenience.

As the central point for all Western Australia dental customers and potential customers, the showroom is the focal point to be able to see and experience the complete range of equipment and consumables Henry Schein Halas has to offer.

If you would like a personal tour please contact Henry Schein Halas on 1300 65 88 22

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.

Henry Schein Halas Managing Director, Mike Covey, and Perth Branch Manager, Gayle Jones, opening the new office.

2 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION VOL. 12, NO. 4

Published in association with

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RESEARCH

The practical application of protective stainless steel bands and wedges for prevention of iatrogenic damage during Class II cavity preparations Tihana Milic1 and Laurence J. Walsh2

Abstract Objectives: This investigation examined the feasibility of using protective devices for preventing iatrogenic damage to adjacent teeth during Class II cavity preparations. It assessed whether protective devices impair direct vision of the cavity, resulting in unnecessary increase in preparation size; and whether their use prolongs preparation time. Methods and Materials: Twenty operators (10 dentists and 10 senior dental students) each prepared Class II cavities on 10 first molar typodont teeth as a baseline, followed by 10 preparations using metal matrix bands as guards on the adjacent teeth, and 10 preparations utilizing interproximal protective wedges with a built in proximal guard strip (FenderWedge®). The time taken was recorded, and the typodonts assessed for the widths and depths of the cavity preparations. Results: There was no significant difference in cavity preparation width or depth for operator experience (P=0.261, P=0.952) and use of either guard (P=0.519, P=0.238). Dentists were significantly faster than students in completing cavity preparations both without and with the use of guards. The cavity preparation time was reduced with the use of guards for students, but remained unaffected by use of guards for dentists. Clinical significance: Using guards did not result in larger cavities, and they were not seen as a hindrance, particularly by less experienced operators who felt more confident when a guard was in place. As guards can prevent iatrogenic damage during Class II cavity preparations, the benefits of their use outweigh any perceived disadvantages.

Keywords: Iatrogenic damage, prevention, Class II cavity preparation, stainless steel bands, wedges Short title: prevention of iatrogenic damage

Introduction

1

Tihana Milic BDSc MPhil The University of Western Australia, Perth, Australia The University of Queensland, Brisbane, Australia 2

Laurence J. Walsh PhD DDSc The University of Queensland, Brisbane, Australia 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

Various methods exist for preventing iatrogenic damage during preparation of proximal surfaces, although none are in widespread use in clinical practice. Currently available devices that would be suitable as guards include stainless steel matrix bands, interproximal tooth separators with shields such as InterGuard® (Ultradent Products Inc Utah, USA) and interproximal wedges which combine a plastic wedge and a stainless steel plate, such as WedgeGuard® (Triodent Ltd, Katikati, New Zealand), FenderWedge® (Directa AB, Upplands Väsby, Sweden), and Palodent Plus Wedgeguard® (Dentsply Caulk, Delaware USA).

The need for such guards stems from the problem of iatrogenic damage during the preparation of Class II cavities or proximal surface reduction. This issue was first noted in 1972,1,2 but attracted little interest, perhaps because potentially effective methods for protecting adjacent teeth were available, although rarely used.3 Bur-caused damage to enamel surfaces adjacent to conventional Class II cavity preparations occurs at relatively high rates, with most studies reporting frequencies in the range of 64 97%,3,4,5,6,7 although one study has reported lower rates of 49% - 60%.8 When enamel surfaces are damaged the inability of patients to remove the accumulated plaque by flossing from the deepest point of enamel grooves and nicks5,9 may result in an increased risk of caries. Furthermore, interproximal radiolucencies from iatrogenic damage may be misinterpreted on bitewing radiographs as new carious lesions,8,10 leading to unnecessary restorative treatment of previously healthy teeth.6,8

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RESEARCH

While the high frequency of damage indicates a need to utilize protective guards as a routine measure, there are no reports of potential disadvantages or risks associated with use of such devices that would explain why they are not utilized in modern dental practice. For instance, some operators may feel that a guard limits their visibility of the Class II cavity being prepared, which could slow the progress of their work or lead to a larger cavity being prepared. Such considerations, if confirmed, would render these devices unusable in clinical practice. This study therefore examined whether the use of interdental guards inserted to protect the adjacent teeth from inadvertent damage alters the dimensions of the Class II cavities being prepared (specifically, whether a larger than necessary cavity is prepared), and whether the presence of a guard prolongs the time needed to complete the cavity preparation. The impact of operator experience as a variable was also considered, by involving both dental students and experienced dentists as operators. The study compared the effects of using as guards either standard metal matrix bands or FenderWedges™ during Class II cavity preparation. The findings would likely also be relevant to the scenario of full crown preparation, where an even higher frequency of enamel damage reportedly occurs.11,12

a series of preparations utilizing standard stainless steel matrix bands placed interdentally. The largest size of FenderWedge (yellow wedges) was used, to create a worstcase scenario in terms of obstruction of visual access. The participants were instructed to follow their normal technique and not to prolong their preparation time in order to minimize the extent of iatrogenic damage. The time taken for each operator to prepare the cavities was recorded using a digital stopwatch. At the end of the phantom head work, the operators were surveyed regarding their experiences of the various protective devices.

The maximum proximal box width and depth of the 20 cavity preparations prepared by each operator under the three situations was measured firstly with digital calipers (model 799A-6/150 Digital Vernier Calipers, LS Starrett Inc, Athol, MA, USA), with cavity width and depth measured to the nearest 0.01 mm. The typodont teeth were then digitized (CEREC Blu-Cam scanner, Sirona Dental Systems, GmbH, Bensheim, Germany) and the dimensions of the cavities measured with PrepCheck® software from the same supplier.

The stated accuracy of the digital scans was 0.019 mm, and all readings from the digital scans and the digital calipers were in agreement within 0.05 mm. A typical image from the digitized teeth is shown in Figure 1.

Methods and materials

Statistical analysis

This study was part of a series of investigations into iatrogenic damage to adjacent teeth during Class II cavity preparations.

A total of 10 final year dental students and 10 experienced general dentists served as operators. All operators worked under simulated clinical conditions, on identical phantom heads, with standardized equipment and lighting. A full, unrestored dentition was present in all typodont sets of teeth.

Because all operators had been trained on Frasaco teeth (Frasaco gmBH, Tettnang, Germany) at the University of Queensland School of Dentistry during their studies, typodont teeth from this same supplier were used for continuity. The teeth were prepared using air turbine handpieces (Pana-Max PAX-TU M4, NSK, Tochigi, Japan) with medium-grit cylindrical diamond high-speed burs (Horico Diamant FG108010, Horico, Berlin, Germany). A standardized cavity preparation method for Class II cavity preparations (MO and DO designs) was utilized.

Each operator initially prepared 10 MO and 10 DO Class II cavity preparations in typodont first molars without the use of any guards, followed by a further set of preparations utilizing FenderWedges® (Directa AB, Upplands Väsby, Sweden) placed interdentally, and finally

The data sets for time taken for cavity preparation were analyzed using JMP® software version 10 (SAS Institute Inc, Cary, NC, USA) with a repeated measures analysis of

Figure 1: Class II preparation imaged using the Sirona CEREC Blu-Cam system showing cavity width measurement for the proximal box.

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MILIC / WALSH

Table 1: Relationships between cavity preparation times for operators and guard use Time, no guard

Time, stainless steel matrix band

Time, protective wedge

Mean

Min

Max

Mean

Min

Max

Mean

Min

Max

Experienced Dentists

7.0

4.1

10

6.8

4.0

9.25

6.9

4.2

9.0

Student

12.8

10.2

15.0

11.6

9.25

13.75

11.3

9.7

13.5

Mean, minimum and maximum cavity preparation times in minutes for experienced dentists and final year dental students for cavity preparations without a guard, with a stainless steel band, and with a protective wedge. variance The data was validated with Mauchly’s sphericity test, to ensure that the variances of the differences between all possible pairs of groups (i.e., levels of the independent variables) were equal, which is an important assumption of a repeated measures ANOVA. The data for changes to cavity preparation widths and depths was analyzed in SPSS® software version 22 (IBM, Armonk, NY, USA). A linear mixed model was fitted to compare the primary outcomes of depth and width of the cavity for students and experienced dentists. The fixed effects in the model were group (experienced dentists and students), device (none, wedge, stainless steel band), group-device interaction and a repetition variable to determine if there was a difference in cavity depth between the first and second preparation.

Correlation between the repeated measures for the devices by preparation repetition combination was modeled using the residual covariance matrix with a compound symmetry structure. While two structures were tested to find the best covariance structure, the compound symmetry structure gave the best results.

Results The gender ratio of the participating operators was 45% female and 55% male. All senior dental students were aged in their early twenties. The age of the dentists was not recorded, however they all had at least 5 years of clinical experience.

Preparation time A repeated measures ANOVA was fitted to the data for times for cavity preparations for experienced dentists and students with and without guards. The sphericity test result was significant (P = 0.000051), indicating a difference in the variance between no guard and the use of a stainless steel band or a wedge. Accordingly, the multivariate F test and

the adjusted univariate F test were then used. The reason for the adjustment is that when the sphericity pattern is not present, the F test may lead to inappropriate rejection of the null hypothesis. Correction of the degrees of freedom using the Greenhouse and Geisser epsilon factor was therefore considered. The univariate G-G and H-F tests were both significant (P=0.0041 and P=0.0031), indicating a difference in time for cavity preparations between dentists and students. There was no difference in time required for experienced dentists to prepare teeth with or without the use of guards, however for students the time needed for cavity preparation reduced when guards were used.

Table 1 presents the least squares mean time for students and experienced dentists to complete one preparation without a guard, with a wedge and with a stainless steel band. The overall preparation time for students was reduced by approximately 1 minute from an average of 12.8 minutes drilling without a guard, to 11.6 minutes and 11.3 minutes with a stainless steel band and with a FenderWedge, respectively.

Preparation width Examination of preparation widths determined values for the Corrected Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) of 290.96 and 299.14 respectively. There was no significant difference between experienced dentists and students in cavity preparation widths (P = 0.261), no significant effect for devices (no protection, use of stainless steel band, wedge, P=0.544), and no interaction between the two variables (P = 0.534).

There was no significant impact of the repetition of preparation (P = 0.093).

As shown in Table 2, there were no significant differences in marginal mean widths for both students and dentists when drilling without a guard, with a stainless steel band and with a protective wedge.

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MILIC / WALSH

Table 2: Cavity preparation widths Mean widths, no guard

Mean widths, stainless steel matrix band

Mean widths, protective wedge

Mean

Min

Max

Mean

Min

Max

Mean

Min

Max

Experienced Dentists

3.3

1.5

5.3

3.0

1.9

5.1

3.3

2.6

5.3

Student

3.4

2.3

4.6

3.5

1.8

4.2

3.5

1.9

4.5

Mean widths (in mm) for students and dentists when drilling without a guard, with a stainless steel band and with a protective wedge.

Preparation depth As was found for preparation width, the protective devices did not cause an increase in cavity depth. Examination of the depth of the preparation determined values for AIC and BIC of 134.92 and 143.10, respectively. No significant differences were found between experienced dentists and students in cavity preparation depths (P = 0.952), no significant difference between the various devices (P = 0.238), and no interaction between the two (P = 0.138).

There was no significant impact of the repetition of preparation (P = 0.726). As shown in Table 3, there were no significant differences between mean depths for use or not of the protective devices (no guard, use of a stainless steel band and use of a wedge) for both students and experienced dentists.

Some 30% of all operators felt that the bands and to a lesser extent the FenderWedges partially obscured their vision, however only 10% of experienced dentists believed they worked slower with these devices in place. Some 90% of students believed that they worked faster when protective devices were present, while 10% noted no difference in their speed of work. Some 95% of operators believed that using protective devices reduced the extent of iatrogenic damage caused.

The feedback survey revealed that students believed they worked faster and with greater confidence when guards were present. One student even noted that: ‘...added protection from iatrogenic damage resulted in reduced [operator] stress while working.’ When surveyed on their experience with the use of the two different protective devices, dentists gave a mixed response. One dentist reported being ‘unused to the presence of a protective device between the teeth, and so probably worked slower than usual initially.’ Others noted that they worked faster as they could take slightly less care (within reason) regarding damaging the adjacent tooth with the protective devices in place. Only one dentist felt that they consistently worked less efficiently when protective devices were present. Three dentists stated that the stainless steel band, and to a lesser extent the smaller stainless steel plate on the FenderWedge partially obscured their vision of the cavity preparation.

Discussion Despite past studies suggesting there would be benefits from using protective devices to prevent iatrogenic damage during conventional Class II cavity and crown preparations,5,8,11,12 these devices are not used commonly in clinical practice.

The expected benefits need to be balanced against potential

Table 3: Cavity preparation depths Mean depths, no guard

Mean depths, stainless steel matrix band

Mean depths, protective wedge

Mean

Min

Max

Mean

Min

Max

Mean

Min

Max

Experienced Dentists

2.9

2.3

3.4

2.7

2.4

3.5

2.9

2.3

3.7

Student

2.9

1.5

3.9

2.9

1.8

3.5

2.8

2.2

4.0

Mean depths of cavities (in mm) for students and dentists when drilling without a guard, with a stainless steel band and with a protective wedge.

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MILIC / WALSH

adverse effects. As caries removal is aided by visual inspection as well as tactile examination methods, there is a potential risk that the obstruction of direct vision could result in an increase in size of and time for cavity preparations.14 The present study did not find a statistically significant change in the width and depth of Class II cavity preparations made by either experienced dentists or senior dental students when protective devices were utilized. The final preparations were of comparable size between the two groups of operators (as shown in Table 1).

The average times taken by dentists and students in the current study to complete a single cavity preparation without guards (7 and 12.8 minutes respectively) are somewhat shorter than those reported in a comparable study by Lussi et al. (14.9 minutes). The participants of the present study were specifically instructed not to prolong their preparation procedures, but rather to replicate as closely as possible their normal clinical working procedures. This could explain the difference in time taken for cavity preparations between the two investigations.

An unexpected result in the current study was that students when using protective devices reduced the average time for cavity preparation by approximately 1 minute or some 8%.

This small impact on productivity is unlikely to be noticeable on a single cavity preparation procedure, as students on average took 63-82% longer than experienced dentists to complete cavity preparations of comparable quality with and without guards. However, students subjectively felt more confident when utilizing guards during their work. One would not expect the level of confidence to be a factor with experienced dentists, and unsurprisingly, using protective devices did not affect the productivity of the dentists. Despite being unaccustomed to their use, only 1 of the 10 dentists subjectively perceived his/her efficiency to be hindered by the use of a guard.

Conclusions Using either a stainless steel matrix band or a FenderWedge did not result in a statistically significant change to cavity preparation width and depth for Class II cavity preparation in molar teeth, nor did it impair productivity. Rather, using a guard gave a small boost (in the order of 8%) to the productivity of less experienced operators, because of greater confidence. Therefore, the benefits of using such protective devices to prevention iatrogenic damage outweigh the commonly perceived risks and disadvantages.

Due to the high reported rates of iatrogenic damage3,4,5,6,11,12 and its potential adverse consequences, there is a sound rationale in using protective devices when preparing proximal surfaces of posterior teeth.

Acknowledgements This work was supported by a grant from the Australian Dental Research Foundation Grant and the 2013 Colin Cormie Scholarship. We thank Ms. Megan Valentine from the Statistical Consulting Unit of the University of Newcastle for expert assistance with statistics, and all the dentists and dental students who participated in the study. The authors declare no potential conflicts of interest with respect to publication of this article or authorship.

References 1. Cardwell JE, Roberts BJ. Damage to adjacent teeth during cavity preparation. J Dent Res 1972;51(Suppl 5):1269-70.

2. Boyde A, Knight PJ. Scaning electron microscope studies of Class II cavity margins. Br Dent J 1972;133(8):331-7.

3. Qvist V, Johannessen L, Bruun M. Progression of approximal caries in relation to iatrogenic preparation damage. J Dent Res 1992;71(7):1370-73.

4. Opdam N, Roeters J, van Berghem E, Eijsvogels E, Bronkhorst E. Microleakage and damage to adjacent teeth when finishing Class II adhesive preparations using either a sonic device or bur. Am J Dent 2002;15(5):31720.

5. Lussi A, Kronenberg O, Megert B. The effect of magnification on the iatrogenic damage to adjacent tooth surfaces during Class II preparation. J Dent 2003;31(4):291-96.

6. Lussi A, Gygax M. Iatrogenic damage to adjacent teeth during classical approximal box preparation. J Dent 1997;26(5-6):435-41.

7. Lenters M, van Amerongen WE, Mandari GJ. Iatrogenic damage to the adjacent surfaces of primary molars, in three different ways of cavity preparation. Eur Arch Paediatr Dent 2006;7(1):6-10.

8. Medeiros VAF, Seddon RP. Iatrogenic damage to approximal surfaces in contact with Class II restorations.

J Dent 2000;28(2):103-10.

9. Radlanski RJ, Jager A, Schwestka R, Bertzbach F. Plaque accumulations caused by interdental stripping. Am

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J Orthod Dentofacial Orthop 1988;94(5):416-20.

10. Baelum V, Heidmann J & Nyvad B (2006) Dental caries paradigms in diagnosis and diagnostic research Eur J Oral Sci 114(4) 263–277.

11. Moopnar M, Faulkner KDB. Accidental damage to teeth adjacent to crown-prepared abutment teeth. Aust Dent J 1991;36(2):136-40.

12. Long TD, Smith BGN. The effect of contact area

morphology on operative dental procedures. J Oral Rehabil 1988;15:593-8.

13. Directa AB (2013) Directa: Design by Dentists; Retrieved online September 14 2013, from http://www.directadental.com/ 14. Silva NR, Carvalho RM, Pegoraro LF, Tay FR, Thompson VP. Evaluation of a self-limiting concept in dentinal caries removal. J Dent Res 2006;85(3):282-6.

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CLINICAL

Consensus statements on bulk fill resin composites Richard Price1

Introduction In the context of this document, bulk fill materials are lightcured, resin-based composites that can be placed in increments of 4 mm (or in a few cases 5 mm) according to the manufacturer.

It is strongly recommended that before using a product, the clinician read and understand the manufacturer’s instructions for use (IFU) because, although different products may appear to be similar, proper procedures can differ significantly among brands and even among shades of the same composite. (Figure 1) Using a bulk fill resin composite (BRC) does not mean that you can bulk cure all restorations with just one light exposure.

Bulk fill resin products can be divided into two subgroups: • Flowable BRC • Sculptable, high viscosity BRC Using the bulk fill and bulk cure approach may save time, reduce the risk of contamination, and reduce the formation of voids (entrapped air) that can be produced when multiple increments of resin are used to restore a tooth. To ensure that the anticipated increment thickness does not exceed the manufacturer’s recommended

Before you start Shade

Exposure Time

A1

10s

A4

20s

1

Richard Price, Professor and Head of Fixed Prosthodontics, Department of Dental Clinical Sciences, Faculty of Dentistry, Dalhousie University, Canada Email: rbprice@dal.ca

Figure 1

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CLINICAL

Before you fill a Class II ...

When you fill ....

Figure 2

Figure 3

thickness, clinicians should measure the maximum preparation depth. In deep preparations, two or more layers of BRC may be necessary. (Figure 1)

When you Light Cure ....

Material Properties In general, the mechanical properties of BRC are similar to those of conventional, hybrid resin composites. The flowable BRCs can have significantly less filler volume, a lower elasticmodulus, and lower hardness than the sculptable, high viscosity BRCs or the traditional, hybrid composites. In general, the translucency of BRCs is greater than those of conventional, hybrid resin composites. This allows more light to penetrate to the bottom of the restoration and improves the depth of cure; however, the BRC may appear somewhat grey in the mouth. Thus, esthetic requirements must be taken into account when using a BRC. Increased debonding at the pulpal floor of deep Class I and II restorations has been reported when bulk curing some BRCs, compared to when an incremental filling technique was used. This observation remains under investigation.

Some, but not all, BRCs use larger filler particles.

Historically, composites with large filler particles have generally shown higher wear rates, which may be clinically relevant if the BRC is not capped with a typical microhybrid or nanohybrid composite. Also, most flowable BRCs should be capped with a traditional sculptable composite to create the occlusal anatomy and to provide an esthetically pleasing, strong and wear-resistant surface. (Figure 3)

Guidelines for success Most of the following recommendations are valid for all light curing composites, not just only for BRCs. The amount of light energy (Dose = Incident Irradiance x Exposure Time) required to ensure sufficient curing of BRCs is not the same for all

Figure 4

products, and the manufacturer’s IFU should be followed closely. (Figure 1)

Recommendations • Check that the matrix band is anatomically adapted and that there is a tight fit especially at the cavosurface margin of the proximal box. (Figure 2) • Light cure the adhesive and the composite in the distal and the mesial boxes separately.

• Pay attention when bulk filling, as it is easy to trap air at the corners of the preparation. (Figure 3) Although warming the composite may help, further studies are required to confirm the benefits of warming.

• The basic premise of exposure reciprocity is invalid and should not be relied upon to calculate minimum exposure

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PRICE

5

5a

5b

5c

Figure 5

times. If the manufacturer recommends delivering 1500 mW/cm2 for 10 seconds, this does not mean that the resin properties will be the same if 5000 mW/cm2 is delivered for 3 seconds, despite the fact that, in both cases, the resin would receive the same amount of energy: 15 J/cm2. (Figure 4) • Using today’s composites, light curing units that deliver greater than 2000 mW/cm2 and claim short curing times (<10s) should be used cautiously, unless clinical studies can verify the claims about the BRC you are using.

Based on the success achieved with longer curing times (10 to 20 seconds), irradiance levels between 10001500 mW/cm2 are preferable.

• It is critical to orient the light source directly over and at 90° to the portion of the restoration being light cured.

(Figure 5a) • Be aware that preparation design and presence of the

•

•

•

•

matrix band may cause light shadows. (Figure 5b) To provide the best light delivery, intentionally move and adjust the angle of the light tip to eliminate these shadows.

Increase exposure time as necessary.

Be aware of the light tip diameter, size of the preparation and the planned restoration. Resin that is at (or beyond) the edge of the light tip is unlikely to be adequately cured.

(Figure 5c) Due to the tooth anatomy, its location in the mouth, and the matrix band, the light tip position may be farther away than desired from the BRC being light cured. This effect is greater in deep preparation areas (e.g., the bottom of proximal boxes). Be aware of these issues and compensate by increasing exposure times.

After removing the matrix band, supplemental light curing from the buccal and lingual directions is highly recommended. (Figure 6) Deliver sufficient amounts of light energy to successfully cure the BRC, but without overheating and damaging the tooth pulp or surrounding exposed gingival tissues. A short 3s delay between light exposures, blowing air, or using high volume suction to draw air across the tooth can reduce the increase in intrapulpal temperature.

Clinical results

Figure 6

So far, no clinical studies show that BRCs are superior to traditional, incrementally placed composites. Some published clinical data show that a few flowable BRC products can be as successful as traditional, incrementally placed composites. More long-term clinical studies are needed before definitive statements can be made about the overall performance of these two groups of products.

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Conclusion BRCs continue to show promise. Based on available in vitro and in vivo research results, most BRCs can be expected to be equivalent to conventional, incrementally cured resin composites in posterior, stress-bearing locations. However, most flowable BRCs will have higher wear rates and should be capped with conventional resin composites or highviscosity BRCs. Incrementally placed composite remains the ‘gold standard’ until more long-term (5+ years) clinical studies provide evidence of similar performance between the two types of products and techniques.

Suggested Additional Reading 1. van Dijken JWV, Pallesen U. Bulk-filled posterior resin restorations based on stress-decreasing resin technology: a randomized, controlled 6-year evaluation. Eur J Oral Sci 2017 May 19 doi: 10.1111/eos.12351. [Epub ahead of print] 2. Van Ende A, Lise DP, De Munck J, Vanhulst J, Wevers M, Van Meerbeek B. Strain development in bulkfilled cavities of different depths characterized using a non-destructive acoustic emission approach. Dent Mater 2017;33(4):e165-e177.

3. Chesterman J, Jowett A, Gallacher A, Nixon P. Bulk-fill resin-based composite restorative materials: a review. Br Dent J 2017;222(5):337-44.

4. Van Ende A, De Munck J, Lise DP, Van Meerbeek B. Bulk-Fill Composites: A Review of the Current Literature. J Adhes Dent 2017;19(2):95-109.

5. Mouhat M, Mercer J, Stangvaltaite L, Ortengren U. Light-curing units used in dentistry: factors associated with heat development-potential risk for patients. Clin Oral Investig 2017;21(5):1687-96.

6. Kalliecharan D, Germscheid W, Price RB, Stansbury J, Labrie D. Shrinkage stress kinetics of Bulk Fill resin-based composites at tooth temperature and long time. Dent Mater 2016 Nov;32(11):1322-31.

7. Van Ende A, De Munck J, Van Landuyt K, Van Meerbeek B. Effect of Bulk-filling on the Bonding Efficacy in Occlusal Class I Cavities. J Adhes Dent 2016;18(2):119-24.

8. van Dijken JW, Pallesen U. Posterior bulk-filled resin composite restorations: A 5-year randomized controlled clinical study. J Dent 2016;51:29-35.

9. Vinagre A, Ramos J, Alves S, Messias A, Alberto N, Nogueira R. Cuspal Displacement Induced by Bulk Fill Resin Composite Polymerization: Biomechanical Evaluation Using Fiber Bragg Grating Sensors. Int J Biomater 2016;2016:7134283.

10. Yap AU, Pandya M, Toh WS. Depth of cure of contemporary bulk-fill resin-based composites. Dent Mater J 2016;35(3):503-10.

11. Ilie N, Stark K. Effect of different curing protocols on the mechanical properties of low-viscosity bulk-fill composites. Clin Oral Investig 2015;19(2):271-9.

12. Tomaszewska IM, Kearns JO, Ilie N, Fleming GJ. Bulk fill restoratives: to cap or not to cap–that is the question? J Dent 2015;43(3):309-16.

13. Ilie N, Stark K. Curing behaviour of high-viscosity 13. bulk-fill composites. J Dent 2014 Aug;42(8):977-85.

14. Masouras K, Silikas N, Watts DC. Correlation of filler content and elastic properties of resin-composites. Dent Mater 2008;24(7):932-9.

Reprinted with permission of the Journal of The Canadian Dental Association

Graphics courtesy of Dr. Richard Price, Professor and Head of Fixed Prosthodontics, Department of Dental Clinical Sciences, Faculty of Dentistry, Dalhousie University, Canada. Email: rbprice@dal.ca

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Prosthetically driven techniques to compensate peri-implant soft tissue deficiencies Urs Belser,1 German Gallucci,2 Kelvin Afrashtehbar,3 Daniel Buser4 Abstract Local soft tissue deficits often follow tooth loss and implant therapy. Under these circumstances, future implant reconstructions should aim to completely or at least partially compensate this loss in order to minimize any adverse effects, namely compromising subjective patient comfort. In the main, this encompasses disconcerting food impaction, as well as esthetic and phonetic impairment. The present article reviews the relevant prosthetically driven compensation measures, confining itself to the esthetic zone of partially dentate implant patients and fixed dental prostheses (FDP). In this specific context five objectives are of paramount importance: (I) establishing healthy peri-implant soft tissues, (II) avoiding open embrasures, (III) maintaining or recreating a harmoniously scalloped soft tissue course, (IV) achieving the optical illusion of balanced relative tooth dimensions, and (V) providing ease of access for effective plaque control. Six representative clinical examples featuring various degrees of peri-implant soft tissue deficiencies are addressed in detail, highlighting different design guidelines and pointing out their inherent limitations. In the case of minor-to-moderate soft tissue deficiencies, achieving the goal by implementing only morphological elements of the so-called white crown substrate such as adequate positioning of facial transition line angles and increased interdental contours is recommended. However, when facing major soft tissue deficiencies, the addition of pink ceramics as an integral part of the implant restoration may become unavoidable to achieve a clinically acceptable result. In this context one has also to take into consideration the position of a given patient’s individual smile line as an important decision-making parameter.

Keywords: Peri-implant soft tissue, implant esthetics, soft tissue deficit, implant-prosthetic design, pink ceramics

1 Prof. Dr. Urs Belser, Guest Professor at the School of Dental Medicine, University of Bern, Switzerland.

Editor-in-Chief of Forum Implantologicum and an Honorary Fellow of the ITI. His research interests focus on esthetics, CAD/CAM technology and high performance dental ceramics as well as on adhesive reconstructive dental medicine.

2 Dr. German Gallucci, Head of the Division of Regenerative and Implant Sciences at Harvard School of Dental Medicine, USA. ITI Fellow and an Editor on Forum Implantologicum, Chair of the ITI Scholarship Center at Harvard University.

Dr. Kelvin I. Afrashtehfar, Research associate at the Division of Oral Health and Society Research, McGill University Faculty of Dentistry in Montreal, Canada. ITI Scholar at the Department for Reconstructive Dentistry and Gerodontology (Head: Prof. Dr. U. Brägger), School of Dental Medicine, University of Bern, Switzerland.

3

4

Prof. Dr. Daniel Buser, Professor and Chairman of the Department of Oral Surgery and Stomatology at the School of Dental Medicine, University of Bern, Switzerland. His main scientific interests include tissue integration of dental implants, guided bone regeneration including autografts and bone substitutes. He has authored/co-authored more than 300 publications. Daniel Buser was ITI President from 2009 to 2013 and has received several awards, among them the Brånemark Osseointegration Award (2013).

Introduction and scope After tooth loss and subsequent implant placement, it is not uncommon for the clinician to face restoration sites featuring a deficit of soft tissue (Araujo & Lindhe 2005; Bidra & Chapokas 2011). The degree and three-dimensional configuration of the resulting peri-implant soft tissue deficiencies depend on both the local preoperative conditions and the surgical protocol used (Buser et al. 2013; Levine et al. 2014; Chappuis et al. 2016). These soft tissue deficiencies concern predominantly the interproximal “papillary” area, followed by mid-facial recessions (Tarnow et al. 2003; Buser et al. 2004). If the new implant-based restoration simply reproduced the originally present anatomical crown volume, it would logically result in open interdental embrasures or so-called “black triangles”. This, in turn, may significantly interfere with the patient’s subjective comfort. In posterior segments of the jaws, the main consequence of open embrasures is disconcerting food collection.

In order to narrow down open embrasure space, restoration volumes are often increased to an unacceptable degree, leading to over-contoured design configurations that contradict the access required for plaque control.

When it comes to the esthetic zone, additional phonetic and esthetic problems arise. The latter is strongly dependent on the height of a given patient’s individual smile line and the degree to which the anterior maxillary alveolar process is exposed (Jensen et al. 1999).

In order to comply with the editorial space restrictions of the Forum Implantologicum, the focus of this article will confine itself to peri-implant soft tissue deficiencies located in the esthetically relevant zone of partially dentate implant patients and review their prosthetically driven compensation techniques.

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Fig. 1a: Initial frontal view of a 49-year-old female patient presenting with two recently inserted single implant restorations at sites 21 and 22. Her main complaint addresses the marked asymmetry (i.e. altered length-to-width ratio) between the implant crowns and their contralateral control teeth. Furthermore, the peri-implant mucosal line is completely lacking a harmoniously scalloped course otherwise present at the adjacent natural dentition.

Fig. 1b: Final situation after removal of the malpositioned implants 21 and 22, followed by the placement of a new implant at site 21, restored with a 2-unit fixed dental prosthesis (FDP) comprising a distal cantilever unit and some pink ceramics as well as the insertion of a new crown on tooth 11. At the patient’s non-forced smile, a significant improvement in terms of symmetry and balanced relative tooth dimensions can be noted.

Fig. 1c: In order to compensate the major vertical soft tissue deficiencies and the resulting esthetic drawbacks, namely in terms of unbalanced relative tooth dimensions, pink ceramics were added to the new restorations. The final adjustments of the latter are performed chair-side to ensure adequate access for Superfloss®.

Fig. 1d: The radiographic control at the end of treatment confirms stable peri-implant bony conditions at the site of the screw-type soft tissue level implant.

Figs 1e - f: At normal communication distance, the patient’s unforced smile displays a harmonious post-operative result in both the frontal (1e) and the oblique (1f) views.

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Main esthetic problems associated with peri-implant soft tissue deficits Negative visual tension arises mainly if the alveolar mucosa is largely exposed during the patient’s unforced smile and one or several of the following conditions are present: • Irregular course of the mucosal line. This points to an absence or interruption of a continuous and harmoniously scalloped soft tissue course. In fact, abrupt vertical position changes of the mucosal margin between neighboring sites are particularly disturbing.

• Open interdental spaces, also widely termed “black triangles”. Such open embrasures not only favor food retention, but they also adversely affect esthetic appearance and frequently cause speech impairment.

• Imbalance of relative tooth dimensions. This describes unnatural length-to-width ratios of clinical crowns, a phenomenon that is often the direct consequence of a lack of peri-implant soft tissue (Sterrett et al. 1999; Magne et al. 2003).

Treatment objectives in the case of peri-implant soft tissue deficits As previously mentioned, the scope of this article discusses only restoration-driven techniques to compensate peri-implant soft tissue deficiencies as the surgical possibilities are specifically presented in two other articles in this issue of Forum Implantologicum. Although the purely implantprosthetic measures are clearly limited, it is not infrequent that they can still help to predictably transform an originally quite compromised situation into one that is acceptable to many patients (Garber & Belser 1995; Belser et al. 1996; Belser et al. 1998; Gallucci et al. 2004; Belser et al. 2006; Vailati & Belser 2007; Spear 2008; Belser et al. 2009; Gallucci et al. 2011; Buser et al. 2013; Wittneben et al. 2013; Boardman et al. 2016; Furze et al. 2016; Moraguez et al.

2016; Tettamanti et al. 2016). One should not forget that the restorative approach clearly helps to reduce the time, cost and complexity of the treatment. Furthermore, it avoids the inherent risk and morbidity of sophisticated surgical interventions. A typical clinical example where this strategy has been implemented is presented in Figs 1a - f.

In general, implant-prosthetic compensation techniques contribute to the following fundamental treatment objectives: • Establishing healthy stable peri-implant tissue conditions and contours • Avoiding or minimizing open embrasure spaces • Maintaining or recreating a regular, continuous and harmoniously scalloped mucosal course

• Achieving the optical illusion of balanced relative tooth dimensions • Providing ease of access for effective daily plaque control

Case presentations In the following paragraphs, five representative clinical examples featuring various degrees of peri-implant soft tissue deficiency are addressed in detail, highlighting different design guidelines and pointing out their inherent limitations.

Situations treated by crown morphology and volume adaptation alone In the presence of minor-to-moderate peri-implant soft tissue deficiencies, it is recommended to aim at compensating the missing volume at the level of the soft tissue (“pink compartment”) by means of morphological adaptation of the crown design (“white compartment”) alone. This strategy is particularly appropriate in the case of a low or intermediate level smile line.

Such favorable pre-prosthetic conditions were present in a 36-year-old female patient eight weeks after insertion of a bone level implant to replace the upper right lateral incisor (Fig. 2a). A minor soft tissue deficit was noted at both the mesial and distal papillary regions as well as on the distofacial aspect of the adjacent central incisor. The three available parameters that allow the creation of the optical illusion of balanced relative tooth dimensions are schematically presented in Fig. 2b. On the one hand the cervical crown volume needs to be slightly increased in comparison to its original size to avoid open embrasures, while on the other one does not want to trade this off against an unbalanced final appearance, i.e. a clinical crown that appears too wide and therefore also too short. This morphological dilemma can be bypassed by moving the mesial and distal transition line angles slightly towards the center of the facial surface, and by likewise giving the midcentral compartment more relative weight in a corono-apical direction. The 6-year follow-up view confirms that the correctly implemented morphological variables helped to reach and maintain a favorable esthetic result that conveys harmony despite the presence of a minor soft tissue deficit (Fig. 2c) and the patient’s gummy smile that completely exposes the site during unforced smiling (Fig. 2e). Furthermore, the corresponding 6-year peri-apical radiograph documents the targeted bony stability (Fig. 2d).

Major vertical soft tissue loss in the papillary area may logically call for more complex compensation techniques.

This is particularly true when dealing with high smile line patients. This is illustrated by the clinical view of a 21-year-

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Fig. 2a: Close-up view of the maxillary right anterior segment of a 36-year-old female patient, 8 weeks after a bone level implant had been inserted at site 12. Note a slight vertical soft tissue deficiency at the facial and distal aspects of the upper right central incisor.

Fig. 2b: Schematic representation of the parameters that can be modified on a maxillary incisor in the case of vertical soft tissue deficiencies to create the optical illusion of balanced relative tooth dimensions (length-to-width ratio): position of the mesial and distal transition line angles, relative weight of the three facial compartments in the corono-apical direction, and palatally located prolonged interproximal contact lines.

Fig. 2c: Clinical close-up view of the maxillary right sextant 6 years after implant surgery. The peri-implant soft tissue deficit has been fully compensated by (1) accentuating the facial transition line angles at their correct anatomical position, and (2) long, palatally located interdental contact lines, including a discreet amount of additional color saturation.

Fig. 2d: The corresponding 6-year peri-apical radiograph documents stable osseointegration and interproximal bone-toimplant contacts located precisely up to the implant shoulder.

Fig. 2e: The patient’s unforced smile documents an acceptable degree of esthetic integration of the implant restoration, despite the presence of a so-called “gummy smile”.

old female patient photographed immediately after delivery of a directly screw-retained implant provisional at site 21 (Fig. 3a). The symmetrical reproduction of the clinical crown form and volume present at the site of the natural control tooth resulted in a major central black triangle. Furthermore, the distal papillary area of the implant site lacked significant height in comparison with the corresponding region between teeth 11 and 12, where a complete interdental soft tissue fill was noted. At this stage the patient refused a second orthodontic treatment, because she still had mixed feelings about a lengthy previous treatment. As a unilateral increase in coronal volume of the implant restoration would not have allowed complete closure of the central embrasure space

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Fig. 3a: Frontal view of a 21-year-old female patient, immediately after inserting a directly screw-retained provisional implant restoration at site 21. A major open embrasure space, termed “black triangle”, can be noted at the midline location. In addition, a distinctly short papilla mesial to the upper left lateral incisor creates significant visual tension in comparison to site 12.

Fig. 3b: In order to restoratively correct the previously described disturbing situation, it was decided to add volume to the mesial aspect of tooth 11. The aim was to reduce the amount of black space and to optically straighten up the slightly inclined long axis of the right central incisor..

Fig. 3c: Without tooth preparation, a mesioincisal partial veneer consisting of feldspar ceramics was produced on a refractory die.

Fig. 3d: The palatal close-up view of the corresponding working model displays the final zirconia-based, directly screw-retained implant crown.

Fig. 3e: The frontal view at the end of treatment documents that the patient’s primary concern, i.e. the large “black triangle”, could be mostly corrected by the non-invasive adhesive restoration at site 11, in combination with an adequately designed implant crown. However, the problem related to the short papilla between implant crown and tooth 22 could only be minimally improved.

Fig. 3f: The postoperative peri-apical radiograph confirms stable bony conditions adjacent to the NNC soft tissue level implant, including the characteristic remodeling and saucer-like crater formation.

due to the mesial inclination of the natural root, but would have led to a marked asymmetry between the two central incisors (one natural and one implant-borne), it was decided to add half of the required volume to tooth 11 in the form of a bonded feldspar veneer fabricated on a refractory model and requiring no tooth preparation, and the other half integrated in the all-ceramic zirconia-based implant crown (Figs 3b - d). This simple and highly conservative approach permitted the efficient elimination of the black triangle (Figs 3e - f). However, the esthetic problem in the form of a short papilla between sites 21 and 22 persisted, as no restorative technique was available to elegantly intervene. The direct

comparison of the clinical views before (Fig. 3g) and after (Fig. 3h) implementing this combined tooth- and implantborne restorative approach shows a marked overall improvement on the one hand, but also some of the limitations of purely prosthetically driven interventions. The patient’s unforced smile, photographed at normal communication distance confirms a predominantly favorable treatment outcome (Fig. 3i).

Situations requiring the addition of pink ceramics In the case of implant-supported screw-retained fixed dental prostheses (FDPs) comprising two or more splinted units and

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Figs 3g – h: The direct comparison before (3g) and after (3h) completion of the combined adhesive and implant-based therapy underlines a marked improvement of a previously – from an esthetic point of view – severely compromised condition, despite the presence of a marked “gummy smile”. On the other hand, the clearly limited restorative possibilities when it comes to the correction of marked vertical soft tissue deficiencies have to be underlined.

the presence of significant vertical peri-implant soft tissue deficiencies, the addition of pink ceramics may nowadays be considered not a last resort but a structured integral part of the implant-prosthetic treatment strategy (Vailati & Belser 2011; Belser & Buser 2012). Sometimes the addition of only a minute quantity of pink ceramics can make a major difference in terms of esthetic appearance. The majority of authors who have published design principles for the use of pink agree that it should be reserved for multi-unit implant FDPs and its extension limited to the zone in between the zenith of the units located at each end of the prosthesis (Barzilay & Irena 2003; Capa 2007; Kamalakidis et al.

2007; Cascione et al. 2008; Coachman et al. 2009; Kim et al. 2010; Papadimitriou et al. 2014; Levin et al. 2015; Moraguez et al. 2015; Papaspyridakos et al. 2016). So called embracing of neighboring teeth by extending the pink

Fig. 4a: Clinical view of the maxillary left sextant of a 46-year-old male patient, taken shortly after the reopening of implant site 23.

It was planned to replace the two missing teeth 22 and 23 with an implant-supported 2-unit fixed dental prosthesis (FDP), featuring a mesial cantilever extension.

Fig. 3i: The patient’s unforced smile, displayed at normal communication distance, also documents a slightly compromised, yet largely acceptable result when comparing the papillary height at embrasures 12/11 and 21/22.

compartment over and beyond the area of the mesial and distal natural papilla makes access for plaque control virtually impossible and can therefore not be recommended.

A typical clinical example of the elegant use of a small amount of pink ceramics is presented in Figs 4a - f. Two months after placement of a tissue level implant at position 23 in a 46-year-old male patient, a flattened edentulous ridge segment including the missing lateral incisor indicated that the planned 2-unit implant FPD featuring a mesial extension would encounter either the problem of an open embrasure at the transition between implant crown and cantilever unit or end up with altered relative tooth dimensions (Fig. 4a). To provide adequate strength in the connecting area, the metal framework was given the required dimension and was positioned as far to the palate as possible (Fig. 4b). Furthermore, a long interdental contact

Fig. 4b: The close-up view of the master model shows the palatal aspect of the directly screw-retained ceramo-metal implant FDP. Note that the metal framework is extended to the lingual surface in order to give maximum strength to the connecting area between the implant crown and the cantilever unit.

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Fig. 4c: For esthetic reasons a small amount of pink ceramic has been added in the papillary region of the 2-unit implant FDP. Note the clearly convex profile of the entire cervical aspect of the restoration.

This is mandatory to create favorable conditions for adequate daily homecare with the use of Superfloss®.

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Fig. 4d: The final clinical view shows the screw-retained, 2-unit implant FDP, featuring a mesial cantilever extension. The determining factors for an optimal esthetic integration consisted of the addition of a minimal amount of pink porcelain, the discreet imitation of a root-like cervical portion at elements 22 and 23 as well as the long interdental contact zone between tooth 21 and the mesial aspect of the cantilever unit.

Fig 4e. The corresponding postoperative peri-apical radiograph documents favorable bony conditions associated with the solid screw-type soft tissue level implant. Note also the adequate dimensions of the underlying metal framework, particularly in the connecting area, to provide optimal mechanical resistance.

line provided intimate contact to the neighboring central incisor tooth to avoid an open embrasure. With respect to the design of the integrated pink ceramic, it was limited to the area between 22 and 23, using a discreet pale shade and given a convex profile to harbor the concavity created on the edentulous ridge (Fig. 4c). The clinical close-up view documents the favorable impact of the added pink in terms of esthetic appearance (Fig. 4d), whereas the corresponding peri-apical radiograph highlights the aforementioned design details, namely the dimension of the underlying metal framework (Fig. 4e). Finally, the photograph taken during the patient’s unforced smile confirms a satisfactory treatment outcome (Fig. 4f).

Fig. 5a: Initial clinical view of a 48-yearold female patient, complaining about a major esthetic problem in the anterior maxilla. This concerns the volume, form and color of the two implant crowns at sites 11 and 21 as well as the open center embrasure space (“black triangle”).

Fig. 4f: The appearance of the upper left anterior segment during the patient’s unforced smile confirms the efficacy of the previously mentioned design elements in terms of natural esthetics.

A next, more challenging example of how the addition of pink ceramics can be instrumental in re-establishing harmonious conditions is presented in Figs 5a - h. The complaints of this 48-year-old female patient were threefold, addressing a disturbing central black triangle, a marked midfacial mucosal recession at implant site 11 and a grossly disproportional volume of the two maxillary central implant crowns when compared with the adjacent natural dentition (Figs 5a - c). Based on the analysis derived from a chair-side diagnostic mock-up it was decided to proceed to the fabrication of two new connected implant crowns with integrated pink ceramics to achieve both the elimination of the black triangle and the re-establishment of balanced

Fig. 5b: The oblique close-up view confirms the aforementioned problems, and additionally highlights the midfacial exposure of the implant shoulder, including the all-ceramic abutment lying above it.

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Fig. 5c: The corresponding peri-apical radiograph shows the presence of two implants replacing the missing teeth 11 and 21, featuring inconspicuous bony conditions.

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Fig. 5d: In order to achieve a more harmonious and balanced whole, the treatment plan comprised the fabrication of two new implant crowns. To allow the adequate implementation of pink ceramics, the new crowns had to be splinted. After carrying out a clinical “mock-up” trial, it was decided to improve the volume, form and length of the adjacent maxillary anterior teeth with minimally invasive adhesive porcelain restorations.

Fig. 5e: On the clinical view after completion of both the new implant crowns 11 and 21 and the veneers 21 and 13, the insufficient clinical crown length of the as yet unrestored teeth 22 and 23 is noticeable. It became obvious at this stage that a surgical crown lengthening procedure was necessary, because the incisal edge position of the two teeth was adequate.

Fig. 5f: The situation after surgical crown lengthening at sites 22 and 23 now confirms more favorable conditions for the planned adhesive restorations.

Figs 5g – h: The direct comparison before (5g) and after (5h) completion of the combined adhesive and implant-based therapy documents a distinct enhancement of a previously quite compromised situation. It must be said that the patient had an ideal smile line position for this kind of restorative design, allowing optimal benefit from the addition of pink ceramics. This in turn allowed the elimination of the black triangle, as well as the re-establishment of balanced relative-tooth dimensions.

relative tooth dimensions (Fig. 5d). To further diminish the disturbing discrepancy with respect to clinical crown height between the implant restorations and the surrounding natural teeth, it was decided to apply minimally invasive ceramic veneers on the other maxillary anterior teeth. On the patient’s right side this was easily possible, as it only required an increase in the incisal edges (Fig. 5e), whereas on the left side a surgical crown lengthening procedure was necessary to accomplish the envisioned treatment objective (Fig. 5f).

From an esthetic point of view, the aforementioned primarily restoration-driven measures led to a treatment outcome that was now acceptable to the patient (Fig. 5g) in comparison with the severely compromised preoperative situation (Fig. 5f).

Conclusions In the case of minor-to-moderate soft tissue deficiencies, it is recommended to achieve the goal by implementing only morphological design elements of the so-called white crown substrate. Among these one should particularly mention adequate positioning of facial transition line angles and increased interdental crown contours including long, orally located contact lines, as well as a discreetly augmented color saturation of the interproximal and cervical regions of the restoration. All these specific aspects are summarized in detail using a representative clinical example (Figs 6a - x).

However, when facing major soft tissue deficiencies, the addition of pink ceramics as an integral part of the implant

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Fig. 6a: Initial frontal view of a 45-year-old female patient with a high smile line exposing an irregular soft tissue course, a mid-facial mucosal recession and chronic marginal infection with swelling at implant site 11, a missing central papilla as well as a visible crown margin at tooth 22.

Figs 6b – c: The corresponding radiographs reveal an axis problem of implant 11, endodontically treated and crowned teeth 12, 21 and 22 as well as a peri-apical chronic infection on root 21.

Fig. 6d: This peri-apical radiograph documents the situation after removal of implant 11 and tooth 21, followed by the staged insertion of two bone level implants according to the concept of early implant placement with simultaneous contour augmentation.

Fig. 6e: At the moment of implant impression, using an “open-try” approach, a marked soft tissue deficiency on teeth 12 and 22, primarily involving the papillary area, can be noted.

Fig. 6f: Close-up view of the palatal aspect of the working model, displaying the two directly screw-retained provisional acrylic implant crowns on titanium copings.

Fig. 6g: On the cervical part of provisional implant crowns, a flat smooth emergence profile is recommended to facilitate efficient homecare with dental floss and/or small interdental brushes.

Fig. 6h: After four weeks the provisional implant restorations favorably contributed to peri-implant soft tissue conditioning and tissue maturation. The level achieved of the periimplant mucosa on the one hand and the gingiva at the adjacent crowned teeth on the other indicates that the final implant crowns will fulfill standard esthetic expectations and that new crowns on teeth 12 and 22 are indicated to assure an acceptable overall integration.

Fig. 6i: Facial close-up view of the four allceramic restorations on the master model at their bisque bake stage.

Fig. 6j: The corresponding palatal aspect shows that the adequate threedimensional implant positioning allowed application of the recommended direct screw-retention design, without interfering with the optimal incisal-edge location or causing a too voluminous cingular area.

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Fig. 6k: In order to benefit from both a zirconia-based all-ceramic restoration and a titanium-to-titanium abutmentto-implant connection, a titanium bonding base termed Variobase® was chosen.

Fig. 6l: The zirconia framework, compatible with the underlying titanium bonding base, and leaving space for minimal final hand layering of cosmetic veneering ceramics, was determined virtually at the computer screen.

Figs 6m – n: Comparison of the two-component titanium-ceramic implant restoration before (6m) and after (6n) provisional assembly. This temporary assembly is necessary to permit a clinical trial at the bisque bake stage.

Fig. 6o: During the clinical bisque bake tryin, the need for minute modifications in color, form and volume can be identified and photographically documented for efficient communication with the dental ceramist.

Figs 6p – q: Facial (6p) and palatal (6q) close-up views of the finalized implant- and tooth-borne all-ceramic restorations. Note in particular the position of the facial transition line angles and the long interdental contact zones.

Fig. 6r: The clinical view of the four final maxillary restorations in maximum intercuspation position confirms a favorable overall integration in terms of form and color.

Fig. 6s: The corresponding peri-apical radiograph reveals optimal peri-implant bony conditions as well as minimal uniform support for the veneering ceramic provided by an optimally designed zirconia framework.

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Fig. 6t: The oblique close-up view permits the design features that were instrumental in compensating the existing moderate vertical soft tissue deficiencies to be highlighted: (i) position and morphology of the facial transition line angles, (ii) long, palatally located interdental contact zones, and (iii) discreet color saturation of the cervico-interproximal crown surfaces as well as the achievement of (iv) healthy soft tissues.

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Figs 6u – v: The direct comparison of the clinical situation before (6u) and after (6v) treatment shows the marked improvement, particularly in terms of a harmoniously scalloped soft tissue course without abrupt changes in vertical position between adjacent teeth and implants, an absence of open embrasures (“black triangles”), and last but not least a favorable degree of balanced relative tooth dimensions.

Figs 6w – x: Similarly, the direct comparison of what is exposed of the anterior maxilla during the patient’s unforced smile before (6w) and after (6z) the described combined implant- and tooth-borne restorative treatment documents satisfying overall esthetic integration.

restoration may become unavoidable to achieve a clinically acceptable result. In this context one must also take into consideration the position of the patient’s individual smile line as an important decision-making parameter. Finally, one has to ensure that the widely established design rules for the use of pink ceramics such as convex profile and access for plaque control are strictly enforced in order not to jeopardize peri-implant tissue health.

Acknowledgements The authors wish to express their gratitude to the following ceramists and laboratory technicians for their knowledge and performance during the fabrication of the various FPDs presented in this article: Alwin Schönenberger, Pascal Müller and Dominique Vinci.

References Araujo, M.G. & Lindhe, J. (2005) Dimensional ridge alterations following tooth extraction. An experimental study in the dog. Journal of Clinical Periodontology 32: 212 - 218.

Barzilay, I. & Irene, T. (2003) Gingival prosthesis – A review.

Journal of the Canadian Dental Association 69: 74 - 78.

Belser, U. C., Bernard, J. P. & Buser, D. (1996) Implantsupported restorations in the anterior region: prosthetic considerations. Practical Periodontics and Aesthetic Dentistry 8: 875 - 883.

Belser, U.C., Buser, D., Hess, D., Schmid, B., Bernard, J.P. & Lang, N.P. (1998) Aesthetic implant restorations in partially edentulous patients – a critical appraisal.

Periodontology 2000 17: 132 - 150.

Belser, U., Martin, W., Jung, R., Hämmerle, C., Schmid,

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B., Morton, D. & Buser, D. (2006) ITI Treatment Guide, Vol 1: Implant Therapy in the Esthetic Zone - Single Tooth Replacements. Editors: Belser, U., Buser, D. & Wismeijer, D., Berlin: Quintessence Publishing Co., Ltd. Belser, U. C., Grütter, L., Vailati, F., Bornstein, M. M., Weber, H. P., Buser, D. (2009) Outcome evaluation of early placed maxillary anterior single-tooth implants using objective esthetic criteria: a cross-sectional, retrospective study in 45 patients with a 2- to 4-year follow-up using pink and white esthetic scores. Journal of Periodontology 80: 140 - 151.

Belser, U.C. & Buser, D. (2012) Replacement of four incisors with a fixed partial denture on two narrow-neck implants after implant failure. In: ITI Treatment Guide, Vol 6: Extended Edentulous Spaces in the Esthetic Zone. Editors: Wismeijer, D., Chen S. & Buser D., Berlin: Quintessence Publishing Co., Ltd. Bidra, A. S. & Chapokas, A. R. (2011) Treatment planning challenges in the maxillary anterior region consequent to severe loss of buccal bone. Journal of Esthetic and Restorative Dentistry 23: 354 - 360.

Boardman, N., Darby, I. & Chen, S. (2016) A retrospective evaluation of aesthetic outcomes for single-tooth implants in the anterior maxilla. Clinical Oral Implants Research 27: 443 - 451.

Buser, D., Martin, W., Belser, U. C. (2004) Optimizing esthetics for implant restorations in the anterior maxilla: anatomic and surgical considerations. International Journal of Oral and Maxillofacial Implants 19 Suppl: 43 - 61.

Buser, D., Chappuis, V., Bornstein, M. M., Wittneben, J. G., Frei, M. & Belser, U. C. (2013) Long-term stability of contour augmentation with early implant placement following single tooth extraction in the esthetic zone: a prospective, cross-sectional study in 41 patients with a 5- to 9-year followup. Journal of Periodontology 84: 1517 - 1527.

Capa, N. (2007) An alternative treatment approach to gingival recession: gingival-colored partial porcelain veneers – a clinical report. Journal of Prosthetic Dentistry 98: 82 - 84.

Cascione, D., Nowzari, H. & Kim, T.H. (2008) Simulated tissue in modern implant dentistry. Spectrum Dialogue 7: 64 - 76.

Chappuis, V., Bornstein, M. M., Buser, D. & Belser, U.C. (2016) Influence of implant neck design on facial bone crest dimensions in the esthetic zone analyzed by cone beam CT: a comparative study with a 5-to-9-year follow-up. Clinical Oral Implants Research 27: 1055 - 1064.

Coachman, C., Salama, M., Garber, D., Calamita M., Salama, H. & Cabral, G. (2009) Prosthetic gingival reconstruction in a fixed partial restoration. Part 1: introduction to artificial gingiva as an alternative therapy.

International journal of periodontics and restorative dentistry.

International Journal of Periodontics and Restorative Dentistry 29: 471 - 477.

Furze, D., Byrne, A., Alam, S. & Wittneben, J. G. (2016) Esthetic Outcome of Implant Supported Crowns With and Without Peri-Implant Conditioning Using Provisional Fixed Prosthesis: A Randomized Controlled Clinical Trial. Clinical Implant Dentistry and Related Research doi: 10.1111/cid.12416 [Epub ahead of print].

Gallucci, G. O., Belser, U. C., Bernard, J. P. & Magne, P. (2004) Modeling and characterization of the CEJ for optimization of esthetic implant design. International Journal of Periodontics and Restorative Dentistry 24: 19 - 29.

Gallucci, G. O., Grütter, L., Nedir, R., Bischof, M. & Belser, U. C. (2011) Esthetic outcomes with porcelain-fusedto-ceramic and all-ceramic single-implant crowns: a randomized clinical trial. Clinical Implant Dentistry and Related Research 22: 62 - 69.

Garber, D. A. & Belser, U. C. (1995) Restoration-driven implant placement with restoration-generated site development. Compendium of Continuing Education in Dentistry 16: 796, 798 - 802, 804.

Jensen, J., Joss, A. & Lang, N.P. (1999) The smile line of different ethnic groups depending on age and gender. Acta Medicinae Dentium Helvetica 4: 38 - 46.

Kamalakidis, S., Paniz, G., Kang, K.H. & Hirayama, H. (2007) Nonsurgical management of soft tissue deficiencies for anterior single implant-supported restorations: a clinical report. Journal of Prosthetic Dentistry 97: 1 - 5.

Kim, T.H., Cascione, D., Knezevic, A. & Nowzari, H. (2010) Restoration using gingiva-colored ceramic and ridge lap pontic with circumferential pressure: A clinical report.

Journal of Prosthetic Dentistry 104: 71 - 76.

Levine, R. A., Huynh-Ba, G. & Cochran, D. L. (2014) Soft tissue augmentation procedures for mucogingival defects in esthetic sites. International Journal of Oral and Maxillofacial Implants 29 Suppl: 155 - 185.

Levin, B. P., Rubinstein, S. & Rose, L. F. (2015) Advanced Esthetic Management of Dental Implants: Surgical and Restorative Considerations to Improve Outcomes. Journal of Esthetic and Restorative Dentistry 27: 224 - 230.

Magne, P., Gallucci, G. O. & Belser, U. C. (2003) Anatomic crown width/length ratios of unworn and worn maxillary teeth in white subjects. Journal of Prosthetic Dentistry 89: 453 - 461.

Moráguez, O., Vailati, F., Grütter, L., Sailer, I. & Belser, U. C. (2016) Four-unit fixed dental prostheses replacing the maxillary incisors supported by two narrow-diameter implants

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- a five-year case series. Clinical Oral Implants Research doi: 10.1111/clr.12895.

Moráguez, O. D., Vailati, F. & Belser, U. C. (2015) Malpositioned implants in the anterior maxilla: a novel restorative approach to reestablish peri-implant tissue health and acceptable esthetics. Part II: Case report and discussion.

International Journal of Esthetic Dentistry 10: 522 - 532.

Papadimitriou, D. E., Chochlidakis, K. M., Weitz, D. S., Wazirian, B. & Ercoli, C. (2014) Surgical and prosthetic management of ridge deficiency for an implant-supported restoration in the esthetic zone. Journal of Prosthetic Dentistry 112: 409 - 413.

Papaspyridakos, P., Amin, S., El-Rafie, K. & Weber, H. P. (2016) Technique to Match Gingival Shade when Using Pink Ceramics for Anterior Fixed Implant Prostheses. Journal of Prosthodontics doi: 10.1111/jopr.12483 [Epub ahead of print].

Spear, F. (2008) The use of implants and ovate ponticsin the esthetic zone. Compendium of Continuing Dental Education 29: 72 - 80.

Sterrett, J.D., Oliver, T., Robinson, F., Fortson, W., Knaak, B. & Russell, C.M. (1999) Width/length ratios of normal clinical crowns of the maxillary anterior dentition in man.

Journal of Clinical Periodontology 26: 153 - 157.

Tarnow, D., Elian,, N., Fletcher P., Froum, S., Magner, A., Cho, S. C., Salama, M., Salama, H. & Garber, D. A.

(2003) Vertical distance from the crest of bone to the height of the interproximal papilla between adjacent implants.

Journal of Periodontology 74: 1785 - 1788.

Tettamanti, S., Millen, C., Gavric, J., Buser, D., Belser, U. C., Brägger, U. & Wittneben, J. G. (2016) Esthetic Evaluation of Implant Crowns and Peri-Implant Soft Tissue in the Anterior Maxilla: Comparison and Reproducibility of Three Different Indices. Clinical Implant Dentistry and Related Research 18: 517 - 526.

Vailati, F. & Belser, U.C. (2007) Replacing four missing maxillary incisors with regular- or narrow-neck implants: analysis of treatment options. European Journal of Esthetic Dentistry 2: 42 - 57.

Vailati, F. & Belser, U.C. (2011) Implant-supported fixed prostheses with integrated artificial gingiva for the esthetic zone: the Pink Power Concept. Forum Implantologicum 7: 108 - 123.

Wittneben, J. G, Buser, D., Belser, U. C. & Brägger, U. (2013) Peri-implant soft tissue conditioning with provisional restorations in the esthetic zone: the dynamic compression technique. International Journal of Periodontics and Restorative Dentistry 33: 447 - 455.

Reprinted with permission of the authors and the ITI International Team for Implantology from Forum Implantologicum, Volume 12/Issue 2/2016.

About the ITI The International Team for Implantology (ITI) is an academic association that unites professionals around the world from every field of implant dentistry and related disciplines. It actively promotes networking and exchange among its membership of currently more than 16,000.

In 37 years, the ITI has built a reputation for scientific rigor combined with concern for the welfare of patients. The organization focuses on the development of well-documented treatment guidelines backed by extensive clinical testing and the compilation of long-term results with the objective of continuously improving treatment methods and outcomes. The ITI funds research as well as Scholarships for young clinicians, organizes congresses and continuing education events, and runs more than 630 Study Clubs around the globe. The organization also publishes reference books such as the ITI Treatment Guide series and operates the ITI Online Academy, a peer-reviewed, evidence-based e-learning platform with a unique usercentric approach. www.iti.org

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From digital planning to the mock-up and final restoration Cyril Gaillard1 and Jérôme Bellamy2 Presentation of a modern work concept on the basis of a veneer fabrication A report by Cyril Gaillard and Jérôme Bellamy, Bordeaux/France “Never promise what you can’t deliver!” Particularly when undergoing esthetically motivated dental treatment, patients should be given a realistic visualization of the final outcome to avoid raising undue expectations.

The demand for cosmetic treatments is also increasing in dental practices. Today’s communication media provide patients with virtually limitless access to a wealth of information on this topic. And with it comes an increase in expectations. This can pose a conundrum to the dentist: patients want to be promised the desired results yet they should not be given undue expectations in the run-up to the treatment.

The challenge One of the challenges in day-to-day dentistry is the fact that the mock-up presented to the patient is produced from a wax-up and is often not consistent with the final outcome of the treatment (e.g. ceramic veneers). Several research studies have been initiated to overcome this problem. The SKYN concept is a result of this research.

The solution The SKYN concept is based on a unique approach: it uses natural tooth shapes to create a mock-up directly in the patient’s mouth. A wax-up is created on the basis of tooth shapes that reflect the anatomy and morphology of natural teeth in terms of height, width, curvature and surface texture.

The predictability of the result is ensured by using CAD/ CAM technology to scan the mock-up, make adjustments in the oral cavity and then mill the veneers to achieve lifelike results. The reproducibility of the mock-up and the accuracy of the result arise, among others, from the performance of the CAD/ CAM system, allowing the expectations of the patient to be met both promptly and effectively.

1

Cyril Gaillard Bordeaux/France

2

Jérôme Bellamy Bordeaux/France Contact 14 Rue Montesquieu 33000 Bordeaux France contact@cyrilgaillard.com

Figure 1: Preoperative situation. Severely stained restorations in the upper anterior region.

It does not bother the patient that her upper lip is asymmetrical and her gum line is visible when she laughs.

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Figure 2: SKYN models (according to Dr Jan Hajtó) for the fabrication of the wax-up

Figure 3: The composite (IPS Empress Direct) is applied into the silicone key.

Figure 4a and b: The composite veneers created with the help of the silicone key show a natural shape and surface texture on the model.

CAD/CAM technologies have brought about a revolution in dentistry. They enable the efficient manufacture of customized ceramic veneers with high accuracy and within a short period of time. Furthermore, the restorations present an accurate copy of the esthetic wax-up. The different working steps involved in the SKYN concept are demonstrated below on the basis of a clinical case.

Clinical case Preoperative situation The patient visited the practice with a request that mainly concerned esthetic criteria. She felt that her anterior restorations looked too yellowish and their shape did not fit in. The restorations had been in her mouth for several years.

They should now be replaced.

First, a series of digital pictures was taken to examine the situation more closely. The patient had a high smile line.

However, the fact that her gums were visible when she smiled and her upper lip was asymmetrical did not bother her (Figs 1a and b). The periodontal apparatus was healthy. The soft tissues did not show any signs of abnormalities either.

Treatment planning We recommended the patient to have the anterior region restored with veneers stretching from teeth 15 to 25 and advised her to have the premolars included in the restoration to achieve a harmonious appearance. The patient agreed with our proposal. We drew up the following treatment plan:

• Wax-up using composite veneers to reproduce the natural shape and texture of the teeth • Mock-up according to the SKYN concept using a lightcuring nanohybrid composite (IPS Empress® Direct) • Intraoral digital data scan of the mock-up • Preparation of the teeth with the help of the mock-up • Digital impression of the preparation using an optical camera • Fabrication of the temporaries • Machining of the glass-ceramic veneers (IPS Empress CAD) • Incorporation of the veneers

Fabricating the wax-up The aim of the ceramic veneers was to give more volume to the teeth. The teeth should appear stronger and longer.

Adjusting the dental proportions was requisite to creating a harmonious appearance between the teeth and the smile on the patient’s face. To create the wax-up, we used the SKYN models (“Anterior Model Set” by Dr Jan Hajtó) as reference (Fig. 2). This is a reproduction of natural teeth. Upon request by the patient, tooth selection was performed with the help of both the DSD program (Digital Smile Design) and the VisagiSMile design and visualization software.

Transfer to the mock-up We created a silicone key of the vestibular surfaces with the help of the wax-up and applied a thin layer of composite

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Figure 5: The mock-up is placed in the mouth. The surfaces are being reworked slightly.

Figure 6: Completed mock-up. Photos and videos are used to assess it.

Figure 7a and b: The surfaces of the mock-up are being reworked slightly.

material into the key using a spatula (IPS Empress Direct) (Fig. 3). Once light cured (Bluephase® with Polywave® LED), the resulting composite veneers for teeth 15 to 25 were placed on the model and stabilized with wax (Fig. 4). Once the wax-up was finalized, it was duplicated and cast in stone.

We created a silicone key from this model to assist the dentist in the preparation of the teeth. The silicone key was created in two steps using two different silicone materials, one with a high hardness (Silico Dur, Cendres+Métaux) and the other with a low hardness (3M ESPE Express). The silicone key served to create the mock-up and the temporaries.

Tooth preparation and data transfer to the lab The mock-up was inserted with the help of the silicone key and the surface texture was reworked using a polishing

system (Astropol®) (Fig. 5). The esthetic effect was validated with photographs and videos. The patient could also inspect the pictures (Figs 6 and 7). Then, the teeth were prepared using a ball-shaped bur whilst the mock-up was in place (Galip Gurel 2003) (Fig. 8). This procedure meets the requirements of minimally invasive dentistry. An impression of the prepared teeth (Fig. 9) was taken using an intraoral scanner and the temporaries were fabricated with the help of the silicone key.

At this point, the dentist is required to take two optical impressions: first, an impression of the prepared teeth and, second, an impression of the temporaries in the mouth. In addition, a conventional silicone impression of the prepared teeth is taken. The dental technician will use this impression to produce a physical model to check the fit and contact points of the milled ceramic veneers.

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Figure 8: Targeted preparation of the teeth with the mock-up in place.

Figure 9: Close-up of the prepared anterior teeth.

Figure 10: The CAD data of the digital impressions of the prepared teeth and the mock-up are superimposed.

Creating the final restoration For the CAD construction, the two data sets (temporaries, prepared teeth) were superimposed in the software (Fig. 10).

Subsequently, the shape of the temporaries was matched to the preparation margins. Each component was examined (preparation margin, thickness, contact points, etc.) separately before the data was transmitted to the milling unit for machining (Fig. 11). For the fabrication of the veneers, we decided to use the IPS Empress CAD Multi blocks, which feature a lifelike shade transition from the dentin to the incisal.

We selected a block in shade A1. Each veneer was positioned in the block in such a way that the translucency of the incisal area matched our requirement. Once the veneers were milled, we checked their fit on the prepared dies of the model and assessed their contact points with each other. The surface texture was lightly reworked (Fig. 12). To achieve a highly esthetic result, we additionally characterized the veneers with Stains and Essence materials (IPS Ivocolor®) before we glaze-fired them (Fig. 11).

Seating the ceramic veneers At the try-in, the shade and fit were checked. All ten veneers showed an excellent fit in the mouth. The next step was adhesive bonding. Prior to the bonding procedure, a rubber dam was placed to isolate the treatment field and keep it dry. As the natural teeth were not discoloured, we were able to use a translucent luting composite (Variolink® Esthetic) to insert the veneers (Fig. 13). The veneers were seated using

Figure 11: Veneers ready for placement

the following protocol: • The restorations were etched with hydrofluoric acid for 60 seconds, rinsed under running water and dried with compressed air.

• The veneers were then conditioned with silane. A universal primer (Monobond® Plus) was applied, allowed to react for 60 seconds and dried.

• The prepared teeth were etched with 37% phosphoric acid gel (Total Etch) and rinsed.

• Fluoride-releasing Excite®F DSC adhesive was applied (without light-curing).

• The veneers, which were coated with luting composite, were seated.

• The luting composite was tack-cured for 1 to 2 seconds (Bluephase with Polywave LED) to facilitate the clean-up of excess luting composite.

• Final light curing of all veneers for 40 seconds • Removal of the rubber dam and occlusal check. At the last step, the restorations were polished.

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Figure 12: Restorations on the model after CAD/CAM-supported fabrication of the ceramic veneers.

The ceramic restorations show an appealing esthetic appearance in the mouth and harmonize beautifully with the smile of the young patient. The planned situation was accurately transferred to the final restoration (Figs 14 to 16).

Conclusion Modern materials in esthetic dentistry allow pleasing results to be achieved with considerably more ease than before. It may be considered a substantial progress that the resulting

Figure 13: Adhesive cementation of the ceramic veneers with a rubber dam in place.

restorations meet not only high esthetic requirements but also essential functional criteria. State-of-the-art planning tools, digital auxiliaries, CAD/CAM-supported manufacturing and promising materials lead to excellent results and ensure high patient satisfaction. However, never mind the CAD/CAM technologies, the skills and experience of a seasoned dental technician will remain indispensable.

Reprinted with permission by Reflect 1/2017

Figure 14: Close-up of the veneers after seating.

Figure 15: Texture and tooth shape look natural and harmonize with each other.

Figure 16: Lip appearance and portray picture (below) with the completed restorations. The expectations of the patient have been met.

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RESEARCH

Analysis of dental cliniciansâ&#x20AC;&#x2122; ability to detect iatrogenic damage, and the possibility of using a low viscosity nano-filled resin to protect damaged surfaces Tihana Milic,1,3 Megan Valentine,2 Sowmya Shetty,3 Laurence J. Walsh3 Abstract Objectives: The existing literature indicates that even with the utmost care, there is a high probability that iatrogenic damage will occur to adjacent teeth during routine Class II and crown preparations, making them three times more likely to be restored. This in vitro study investigated whether operator experience increases their ability to detect damage on approximal tooth surfaces. The possibility of treating iatrogenically damaged surfaces with a low-viscosity nano-filled adhesive resin was also examined. Methods and Materials: A total of 17 second year dental students and 10 experienced dentists examined 5 sets of typodont teeth in phantom heads. The first molars had Class II cavity preparations. Any iatrogenic damage of the adjacent teeth was recorded, and the detection and correct classification of damage were analyzed with regard to operator experience and tooth position. A total of 10 extracted natural teeth with varying types of iatrogenic damage were coated with a low-viscosity nano-filled resin (G Coat Plus) and the defects examined using SEM before and after treatment. Results: There was no difference between experienced dentists and second year students in their ability to detect the presence of damage (P=0.710). However, experienced dentists were significantly better at classifying the type of damage present (P=0.008). For upper molar preparations, tooth surface 25 distal was the easiest surface for both dentists and students to correctly classify in terms of defects (P<0.0001). SEM imaging revealed that the resin could uniformly coat shallow to moderate defects, and reduced surface roughness. Clinical significance: Both experienced dentists and students are able to detect the presence of iatrogenic damage in approximately 80% of instances. Experienced dentists are significantly better than students at correctly classifying the damage present. Once detected, the impact of iatrogenic damage could be reduced by applying a low viscosity resin.

Keywords: Detection, iatrogenic damage, prevention, Class II cavity preparation, coverage Short title: detection and coverage of enamel surface damage

Tihana Milic BDSc MPhil Megan Valentine Sowmya Shetty, PhD Laurence J. Walsh PhD DDSc 1

The University of Western Australia, Perth, Australia

2

The University of Newcastle, Newcastle, Australia

3

The University of Queensland, Brisbane, Australia

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

Introduction Iatrogenic damage occurs frequently in restorative dentistry, with a reported frequency of 64-100% for approximal surfaces adjacent to Class II cavity and full crown preparations.

Iatrogenic damage can be scratches, grooves, indentations, or extensive damage, which is a combination of the three types. The consequences of iatrogenic damage to approximal enamel include a greater risk of caries initiation due to the changed topography, and the possibility of unnecessary restoration due to misinterpretation of defects as caries on bitewing radiographs.1-4 A further issue is that removal of the surface enamel layer leads to increased permeability of the enamel to acid,5,6 a parameter which can be reduced by subsequent coating with an adhesive resin.6 This raises the possibility of utilizing an adhesive resin or flowable composite resin to cover areas of iatrogenic damage to reduce the risk of caries development. The same concept could employ novel infiltrative resins, which can penetrate pores in the enamel and provide a physical barrier to acid diffusion.7-10 Such infiltrants have been used for interproximal application.11 Studies examining the effectiveness of infiltrant resins versus conventional adhesives (bonding resins) for protection against acid demineralization adjacent to orthodontic brackets have found that use of an adhesive in combination with the infiltrant, or adhesive alone were both more effective than infiltrant alone.12, 13

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Figure 1: Detection of the presence/absence of damage on teeth for both Students and Experienced Dentists combined.

This laboratory study examined the ability of operators to detect and classify iatrogenic damage in typodent teeth. The possibility of coating iatrogenically damaged surfaces with a low-viscosity, nano-filled adhesive resin was also examined using scanning electron microscopic imaging of defects in natural teeth.

Methods and Materials To assess detection of defects, 17 second year dental students and 10 experienced dentists examined 5 sets of typodont teeth in phantom heads, where the first molars had previously undergone Class II cavity preparation by experienced dentists. The second year dental students were aged from 18 to their mid-twenties, while the age of the experienced dentists was not recorded.

The 27 operators examined typodont teeth adjacent to the pre-prepared first molars for iatrogenic damage, employing a modified version of the classification used by Medeiros et

al. in 2000.14 Operators were requested to identify by visual or tactile examination whether iatrogenic damage was present on the premolar and second molar teeth, and as well as to classify any damage detected. The classification of defects included scratches, indentations, grooves, and extensive damage. As a gold standard, teeth were initially examined using 3X magnification and the type of damage characterized, then the teeth scanned utilizing a non-contact 3D scanner (ATOS Gesellschaft fĂźr Optische Messtechnik GR, GOM mbH, Braunschweig, Germany). The depths of damage were recorded for each tooth.

The classification used for damage was explained to all operators both visually and in print form, and sample images of different types of damage were provided to each operator. To ensure that the second-year dental students had sufficient understanding of iatrogenic damage, a lecture on that topic was included as part of the overall training. Once all operators had completed their assessments, the teeth were

Table 1: Initial analysis of operator ability to correctly detect the presence/absence of damage and to classify the type of damage at varying depths Depth of damage

Experienced Dentists (ED) % Damage Detected

% ED Correctly Classified

Student (S) % Damage Detected

% S Correctly Classified

0 to 119

68.8%

60.0%

68.8%

51.1%

120 to 210

90.0%

47.5%

86.8%

32.4%

211 to 310

90.0%

52.5%

94.1%

36.8%

311 to 540

100.0%

55.0%

100.0%

41.2%

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Table 2: Operator detection of the presence/absence of damage Operator

Mean

Std. Error

95% Confidence Interval Lower

Upper

Student

0.798

0.019

0.758

0.833

Experienced Dentists

0.809

0.024

0.758

0.851

removed from the models and inspected again using 3X magnification for any additional damage caused by operators during their tactile examination.

To explore the viability of protecting damaged surfaces by coating with a low-viscosity nano-filled resin, 20 natural teeth were mounted vertically in groups of two. During cavity preparation in the first tooth, the bur was allowed to ‘slip’ on occasion to damage the adjacent tooth, simulating a most common cause of iatrogenic damage from clinical practice.

The damage on the adjacent teeth ranged from shallow scratches to deeper grooves and indentations.

The teeth were coated with a low-viscosity nano-filled resin (G Coat Plus™, GC Corporation, Tokyo, Japan) that was light cured according to the manufacturer’s instructions. Teeth were sputter coated with gold to a thickness of 2-5 nm and viewed on an FEI Quanta 200 SEM under high vacuum conditions at 10 kV with an Everhart-Thornley detector, at a working distance of approximately 14 mm.

version 21, applying a generalized linear mixed model with a dichotomous outcome variable. The most appropriate covariance was selected using the Corrected Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC).

Results The examination of teeth at the end of the study did now reveal additional damage to the teeth from the explorers used to detect damage.

Operator ability to detect damage, and operator ability to correctly classify the type of damage were analyzed using SPSS

Detection of damage In terms of operator ability to detect the presence or absence of damage, all operators could detect damage deeper than 310 µm, and >86% of operators detected damage >120 µm in depth (Table 1).

There were no significant differences between experienced dentists and students in their ability to detect the presence of damage (P=0.719). Both students and dentists detected around 80% of the areas of damage (estimated marginal means 0.798 (confidence interval 0.758-0.833), and 0.809 (CI 0.745-0.851, respectively), as summarized in Table 2.

Figure 2: Classification of correct type of damage by Students and Experienced Dentists

Figure 3: Estimated marginal means of classification of type of damage for Students and Experienced Dentists combined

Statistical analysis

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Table 3: Classification of type of damage on different teeth Tooth

Mean

Std. Error

95% Confidence Interval Lower

Upper

15D

0.475

0.047

0.384

0.568

17M

0.363

0.045

0.279

0.456

25D

0.741

0.040

0.656

0.812

27M

0.450

0.047

0.360

0.543

35D

0.560

0.047

0.467

0.649

37M

0.466

0.047

0.375

0.559

45D

0.521

0.047

0.428

0.612

47M

0.583

0.046

0.490

0.670

There was a statistically significant difference between performance according to the site of the damage (P<0.0001), with the 15 distal surface being the most difficult tooth for all operators to score correctly, as shown in Figure 1. There was also a significant difference in operator detection of damage between the various models containing the teeth (P<0.0001), with model 1 being more difficult than models 2, 3 and 4 for operators to detect damage on. The interaction between operator and model (P<0.0001) was also significant, indicating different proportions of

Figure 4: SEM images of damage of moderate depth following nano-filled adhesive resin coverage, where A and C represent a groove and indentations respectively, and B shows a porosity present within the resin.

experienced dentists and students detected damage on different models with changing levels of accuracy.

Classification of damage In terms of correct classification of type of damage, the performance of experienced dentists was significantly better than that of students (mean 0.460 (CI 0.406-0.526) versus 0.583 (0.511-0.652), respectively) (P=0.008), as shown in Figure 2.

There were significant differences in classification of damage according to site for both groups of operators (P<0.0001), as shown in Table 3 and Figure 3. Tooth surface 25 distal was the easiest surface for all operators to classify correctly (mean 0.741, CI 0.656-0.812), with 74% of operators correctly classifying damage on this surface. It was more difficult for operators to classify damage on the 17 mesial than on 25 distal or 47 mesial.

There was a difference between the models used (P<0.0001), as shown in Table 4, with model 4 being easier for operators to classify damage on than models 1 and 5.

Attempted repair iatrogenic damage by a low viscosity resin SEM examination showed that application of resin gave adequate coverage of scratches to the enamel. The nanofilled resin covered deeper grooves and indentations, but these remained as undulations in the surface. The resin could not adequately cover areas of deep damage. A small number of porosities were noted within the resin that were attributed to incorporation of air during application rather than defects present on the tooth surface.

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Table 4: Classification of damage on different models 95% Confidence Interval

Sets of Models

Mean

Std. Error

1

0.437

0.039

0.362

0.516

2

0.578

0.040

0.498

0.653

3

0.564

0.040

0.484

0.640

4

0.631

0.038

0.553

0.702

5

0.399

0.039

0.326

0.477

Discussion The results of this study show that once properly trained, dental students can perform equally well as experienced dentists at detecting when damage has occurred to approximal surfaces adjacent to cavity preparations. There was however an important difference between operators, with experienced dentists significantly better than students in correctly classifying the type of damage. This latter difference is expected because of the clinical experience of the dentists with the use of explorers, while the second year students have yet to begin clinical practice.

Tooth surface 15 distal was the most difficult tooth for all operators to detect the presence or absence of damage on.

In 4 of the 5 models used, the surface had no damage, while on the remaining model the damage was a scratch. This may indicate the challenge in exploring this surface for a right handed operator. Conversely, tooth surface 25 distal was the easiest tooth to classify. This surface is easier to see and to explore with an instrument for a right handed operator.

Applying the nano-filled resin could uniformly coat and repair minimal defects such as scratches, but a higher viscosity material such as a flowable composite resin would be needed for moderate defects such as grooves and indentations. When using a resin, care must be taken to prevent trapping air bubbles as it is applied into the defect.

The authors also considered the possibility of the porosities also being caused by the high vacuum required for SEM imaging, since this was undertaken within 30 minutes of applying the resin onto the teeth. Evaporation of volatile constituents remaining within the resin could lead to bubble formation, most commonly by heterogeneous nucleation at a solid-liquid interface. 15 For clinical purposes, the resin used is sufficiently set within 20 seconds of light curing following application.16 Ensaff et al. reported that the

Lower

Upper

majority of polymerization shrinkage within dental composite resins occurs within 300 seconds.17 Thus, it was not considered likely that the high vacuum conditions of the SEM caused the defects in the resin.

In conclusion, the study found that both experienced dentists and students are able to detect the presence of iatrogenic damage in around 80% of cases. This means that assessing the adjacent teeth for damage should be a step during the preparation of Class II cavities and full crown preparations. When damage is found, a suitable adhesive material can be applied to the damaged surface, with a nano-filled low viscosity resin for shallow damage such as scratches, and flowable composite resin for more extensive damage. This can be done before the tooth from the original operative procedure is restored, when access to adjacent surfaces is excellent.

Acknowledgements This study was supported by the Australian Dental Research Foundation through both a research grant and the 2013 Colin Cormie Scholarship. The authors thank all operators for their participation. We also thank Mr. Kevin Warwick of ScanXpress, and Dr Peter Hines of the QUT CARF. The authors declare no potential conflicts of interest with respect to publication of this article or authorship.

References 1. Qvist V, Johannessen L, Bruun M. Progression of approximal caries in relation to iatrogenic preparation damage. J Dent Res 1992;71(7):1370-1373.

2. Lussi A, Gygax M. Iatrogenic damage to adjacent teeth during classical approximal box preparation. J Dent 1997;26(5-6):435-441.

3. Lussi A, Kronenberg O, Megert B. The effect of magnification on the iatrogenic damage to adjacent tooth surfaces during Class II preparation. J Dent 2003;31(4):291-296.

4. Long TD, Smith BGN. The effect of contact area morphology on

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operative dental procedures. J Oral Rehabil 1988;15(6):593-598.

5. Kuhar M, Cevc P, Schara M, Funduk N. Enhanced permeability of acid etched or ground dental enamel. J Prosthet Dent 1997;77(6)578-82.

6. Kuhar M, Cevc P, Schara M, Funduk N. In vitro permeability and scanning electron microscopy study of acid-etched and ground enamel surfaces protected with dental adhesive coating. J Oral Rehabil 1999;26(9):722–30.

7. Meyer-Lueckel H, Bitter K, Paris S. Randomized controlled clinical trial on proximal caries infiltration: three-year follow up. Caries Res 2012;46(6):544-48.

8. Meyer-Lueckel H, Paris S. Improved resin infiltration of natural caries lesions. J Dent Res 2008;87(12):1112–1116.

9. Paris S, Hopfenmuller W, Meyer-Lueckel H. Resin infiltration of caries lesions: an efficacy randomized trial. J Dent Res 2010;89(8):823–826 10. Paris S, Meyer-Lueckel H. Infiltrants inhibit progression of natural caries lesions in vitro. J Dent Res 2010;89(11):1276–1280.

11. Pitts NB, Longbottom C. Temporary tooth separation with special reference to the diagnosis and preventive management of equivocal approximal carious lesions. Quintessence Int 1987;18(8):563–573.

12. Yetinker E, Wegehaupt FJ, Attin R, Attin T. Caries infiltrant

combined with conventional adhesives for sealing sound enamel in vitro. Angle Orthod 2013;83(5):858-63.

13. Schmidlin PR, Sener B, Attin T, Wiegand A. Protection of sound enamel and artificial enamel lesions against demineralization: caries infiltrant versus adhesive. J Dent 2012; 40(10):851–856.

14. Medeiros VAF, Seddon RP. Iatrogenic damage to approximal surfaces in contact with Class II restorations. J Dent 2000;28(2):103-10.

15. Sul IH, Youn JR, Song YS. Bubble development in a polymeric resin under vacuum. Polym Eng Sci 2012; 52(8):1733-1739.

16. G-Coat Plus [Internet] 2009 [cited October 14 2013].

Available from: http://www.gcamerica.com/ products/operatory/G-Coat_Plus/G-Coat%20Plus_IFU.pdf 17. Ensaff H, O’Doherty DM, Jacobsen PH. Polymerization shrinkage of dental composite resins. Proc Inst Mech Eng H 2001;215(4):367-375.

1

This work was supported by a grant from the Australian Dental Research Foundation Grant and the 2013 Colin Cormie Scholarship.

Mr Kevin Warwick of ScanXpress provided access to the ATOS noncontact 3D scanner, and Dr Peter Hines of the QUT CARF provided access to the FEI Quanta 200 SEM. Operators participating in this study utilized the University of Queensland School of Dentistry preclinical laboratory and its equipment.

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CLINICAL

What should you look for in a curing light?

A panel discussion with Howard Strassler,1 Joe Oxman2 and Frederick Rueggeberg3

Introduction For long-lasting, durable restorations, one must select the right curing light for the practice.

But sifting through manufacturer’s claims and deciding what type of curing light to choose can be a daunting task. To help shed some light on this question, The Canadian Dental Association (CDA) convened a panel discussion with three light curing experts, Howard Strassler (HS), Joe Oxman (JO) and Frederick Ruggerberg (FR), who attended the 2014 Symposium on Light Curing in Dentistry in Halifax, Canada.

On the importance of access HS: From a clinician’s viewpoint, access is a very important criterion. I want to be able

1

Howard Strassler, Professor and Director of Operative Dentistry, Department of Endodontics, Prosthodontics, and Operative Dentistry, University of Maryland School of Dentistry, USA .

2

Joe Oxman, PhD (Organic Chemistry). Corporate scientist, 3M Oral Care Systems Division.

3M Director of Research for the Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota, USA.

3

Frederick Rueggeberg, Professor and Section Director of Dental Materials, Dental College of Georgia, Augusta University, Georgia, USA.

to access the tooth I’m restoring from the occlusal, buccal, and lingual aspects, knowing full well that not every patient can open their mouth adequately to get full access. A curing light should work well for both adult and pediatric patients with the light held at right angles to the surface and as close as possible without interfering with the composite.

On the importance of light intensity JO: From my perspective as a photopolymer scientist, I believe there are several key factors one should investigate when you are considering buying a new curing light.

The curing light should have enough intensity to ensure a good and comparable cure at both the top and bottom of the composite restoration, without generating too much heat. I would suggest lights with intensity values of 750 to no more than 2,000 milliwatts per square centimetre. Those with outputs higher than this amount potentially generate excessive heat, without curing the composite any faster. Most recent studies show that higher intensity does not result in shorter curing times due to the nature of today’s curing chemistries. One should follow the suggested curing times of the composite manufacturer and not that of the light manufacturer.

On the importance of choosing a blue-only or a multiwave/multipeak curing light FR: With LED-based curing lights, you’re usually faced with 2 choices: a light that emits only blue light or a light that emits both blue and violet light, also known as a multiwave (or multipeak) light. A blue-only LED light activates a photoinitiator in the restorative

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CLINICAL

Tips for success in light curing*

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STRASSLER / OXMAN / RUEGGEBERG

material called camphorquinone, whereas a multiwave light polymerizes materials by activating both camphorquinone and an alternative initiator. What difference does it make?

Materials with both an alternate initator and camphorquinone—the ones you expose to a multiwave light—will cure better at the top surface than if you use a blue-only LED light. However, the blue light penetrates very deeply into the composite and that’s where the bulk strength of the material comes from. With a blue-only light, the blue output is much more intense compared to the blue output of a multiwave light, so it’s a tradeoff. You’re likely going to optimize curing performance if you select a light and a specific composite from the same manufacturer—but you often don’t have that luxury.

JO: I would argue that, based on today’s light curing chemistries and much of the supporting literature and data, those curing lights with 2 distinct LED wavelengths may or may not provide any additional benefit to the curing chemistry itself. The bottom line is, I think we need to keep things simple.

HS: In general, a buyer of a multiwave light also needs to be aware that the blue and violet light-emitting diodes are placed in distinct locations in the curing light head. The section of the light head that has the violet LED will not effectively cure the surface of a composite that is only blue light sensitive. This means when the light illuminates the surface of a restoration, one area is exposed to violet light and another area is exposed to blue light. The locations of where the violet and blue lights fall within the cavity preparation become of clinical relevance.

On the importance of a uniform light beam JO: I believe it’s important to select a curing light that provides a light beam that is relatively homogenous or uniform over the entire tip at clinically relevant distances, somewhere between 3–10 mm. Preferably, the light should not have a distribution of what I call cold or hot spots; the goal is to ensure an even curing across the entire restoration.

Reprinted with permission of the Journal of The Canadian Dental Association

* Graphics based on Halifax 2014 Symposium on Light Curing, courtesy of Dr. Richard Price, Professor and Head of Fixed Prosthodontics, Department of Dental Clinical Sciences, Faculty of Dentistry, Dalhousie University, Canada. Email: rbprice@dal.ca

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STRASSLER / OXMAN / RUEGGEBERG

Tips to help you choose your next curing light*

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A Congolese Dental School – creating change six students at a time

Dr Graham Toulmin AM and his wife Wendy, also an AM, began developing dental work in the Democratic Republic of the Congo (DRC) when it was known as Zaire and ruled by the dictator President Mobutu Sese Seko. Their family with 4 small boys lived there from 1987 till 1991 and then, with the country undergoing massive inflation and breakdown of law and order, with a coming civil war brewing, and after two evacuations to Kenya in two months, the family returned home. However Graham began doing short term visits to help the clinic, named after his wife – Clinique Dentaire Mama Wendy – to survive. And survive it did, through two civil wars that caused the deaths of 5 million people, because of the faithfulness and courage of the three dental officers, Timon, William and Ringo, that Graham had trained in his early years there.

In 2014, with retirement in his sights, Graham had an anonymous donor come forward with a large donation to fund the building of a dental training institute in Aru, 600 kms to the north of the Mama Wendy clinic. This was a strategic move in a country still unstable in some regions as the clinic-institute would be close to the Ugandan border and safer than some places in eastern DRC. With government approval for a course that was aiming to turn out dentists with practical and clinical competencies, Ringo, with nursing qualifications in his background, enrolled as he had been trained by Graham and others as an ‘apprentice’ and although he had worked for 20 years as a dentist, the government was now demanding government-approved qualifications. The problem the foundling dental school encountered was that there were no qualified teachers of dentistry available to head up the work in this area of DRC. Graham and Wendy, in visiting Aru with Keith Mentiplay to plan the building in September 2016, saw the state of teaching by nondental personnel (the students were carving teeth out of soap and cutting cavities with scalpels as their practical work) and felt they needed to help.

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They had no idea of the immensity of the task ahead of them as Graham was made ‘Chef du Section Dentaire’ and Wendy, by default, fell into the task of Administrator and Bursar with Building supervision on the side. The last two years were pretty tough, especially teaching dentistry in French and surviving with basic living conditions of no water supply or electricity, but they both somehow managed and the Dental Institute was opened on the 12th November 2015 to great fanfare in the community. The first group of students graduated in July 2016 with Ringo the top student in the whole superior training institute, the second group in July this year, and in October 2017, 6 new students began a revised and more practical three year dental course focusing on competencies in the clinic and problem-based learning.

The Dental Institute is unique in Congo. It has 8 fully functioning Adec 500 chairs which Keith Mentiplay installed and which a young technician that he trained, continues to maintain. It has a dental laboratory, sterilisation room, offices and classroom/library, waiting room and reception, two external generators and a water supply from tanks. It is a million dollar dental clinic funded and supplied from Australia and it is now self sufficient. There really is nothing like it in the whole country of DRC, which is the size of Western Europe, and where well-trained dental practitioners are few and far between.

The general population in the country live in tremendous poverty with many health issues, political challenges including dangerous militias and rebel groups in some eastern parts of the country and the dental problems that come along are never simple. Often one mandibular fracture a week due to motor bike accidents and no helmets.

Until Dr Toulmin arrived, there was little to no hands-on training for future dentists except in the capital 2000 kms away but even that had 400 students but only 7 chairs, often not working. Thus students were forced to learn a theory-based syllabus and would graduate never having given an injection, done an extraction or a restoration. This

is a recipe for disaster when presented with a live human patient!

After their 2 years away, Graham and technology-savvy Wendy have returned to Sydney for a month with many fabulous war stories to tell. These include some daily struggles like not having the creature comforts we are so used to here in Australia, like running water, all the way to bureaucratic hurdles needed to be ‘jumped’ for appropriate visas for visiting dentists. Even in their down-time there are jobs to be done! In June after the students finished their exams, they were flown to Garamba National Park where over 2 days they examined and treated 86 of the 250 Park Rangers who patrol the park and protect the elephant population (1347) from poachers. These valuable rangers also protect the local community from the Lord’s Resistance Army (a rebel group and vicious religious cult who have committed atrocities in Northern Uganda, South Sudan, the Central African Republic and the DRC). Without their visit these important community members would have no access to dental care.

Their month long visit home to Australia was busy with speaking engagements, seeing friends and sponsors, sourcing supplies for the clinic, getting replacement parts unavailable in Uganda or Congo and getting medical tests.

Wendy met up with Henry Schein Halas technicians to systematically work through how to get the Aru OPG machine working and this will be the first OPG in eastern Congo for more than 1000 kms. Graham and Wendy were very grateful for the dental supplies and teaching resources that Henry Schein Halas was able to provide and lunch with Gordon Anderson and Jessica Chasen a highlight. The work has moved ahead with the help of Henry Schein Halas over the last twenty years, an aid project that hasn’t crashed and burned, and in March 2018 will celebrate its 30th anniversary. The Toulmins have returned to Congo for a final two years to begin the transition to Congolese leadership and selfsufficiency and we look forward to hearing their news when they return.

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PRODUCTS

QUINTESSENCE

VOCO

QDT 2017

GRANDIO®SO X-TRA

Silla Duarte, Jr (Editor) QDT 2017 celebrates its 40th anniversary in style with beautifully presented original articles on new materials and techniques for achieving the utmost esthetic restorative results.

This year’s focus is on challenging esthetic cases, treatment planning for various restorative options, new techniques using zirconia, and taking CAD/CAM beyond its limits. The State of the Art article presents the RAW digital workflow, and the Biomaterials Update features the Adhesive Restorative Complex concept. QDT’s new Masterclass article addresses the challenge of restoring a single central incisor.

And the Masterpiece article this issue, presented by Naoki Hayashi, is a visual display of dental artistry.

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The aesthetic bulk-fill material in VITA shades GrandioSO x-tra, nano-hybrid bulk restorative amazes with outstanding physical properties, excellent handling and reliable curing in 4-mm layers. With a filler content of 86% by weight, a volume shrinkage of just 1.4% by volume and low shrinkage stress, GrandioSO x-tra is a bulk fill composite in a class of its own, offering toothlike and durable restorations in the shades A1, A2 and A3 as well as a universal shade. The universal U shade boasts a particularly short curing time of just 10 seconds, ideal for patients displaying poor compliance, for example when performing restorations in deciduous teeth in paediatric dentistry.

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

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PRODUCTS

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*Unwaxed Ruscello floss is indicated for use in the dental practice

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For those who don’t floss consistently, AirFloss Ultra Black is the easiest way to effectively clean between teeth. It can be used with mouthwash or water is clinically proven as effective as floss or gum health*

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VITA ENAMIC multiColor is the hybrid ceramic blank for reproduction of the natural shade gradient at the push of a button. This CAD/CAM blank disposes of an integrated shade gradient from cervical to incisal area.

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The Ultimate simplification for all posterior restorations. One shade now available in 3 viscosities. When GC Introduced Essentia it opened the door to a world of simpler restorative dentistry. Now that door is thrown wide open with Essentia Universal shade. Essentia Universal shade offers complete flexibility and simplicity for all posterior restorations.

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