International Dentistry Australasian Edition - Vol.12 No.2

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VOL. 1 2 NO. 2 IN THIS ISSUE

Jan-Frederik Guth and Hans-Jurgen Stecher Aesthetic rehabilitation and tissue preservation in the anterior region Luke Hutchings A minimally invasive approach to brown and white lesion removal Karyn M. Halpern and Bill Marais Lisi Press monolithic crowns Andrew Chandrapal Direct restorations: the last 10 years Karsten Kรถnig and Anton Kasenbacher Thermal damage behaviour of human dental pulp stem cells Gerhard Werling Minimally invasive inlay restoration from the hybrid ceramic VITA ENAMIC Mauricio Watanabe Minimally invasive veneer restoration with ceramic-based restorative material Gualtiero Mandelli and Carlo Borromeo Evaluating the fit of removable dentures with magnification systems

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Contents Volume 12 No. 2

4

Clinical

10

Clinical

Aesthetic rehabilitation and tissue preservation in the anterior region Jan-Frederik Guth and Hans-Jurgen Stecher

10

A minimally invasive approach to brown and white lesion removal Luke Hutchings

18 Clinical

Lisi Press monolithic crowns Karyn M. Halpern and Bill Marais

24 Clinical

Direct restorations: the last 10 years Andrew Chandrapal

24

30 Clinical

Thermal damage behaviour of human dental pulp stem cells Karsten KĂśnig and Anton Kasenbacher

38

Clinical Minimally invasive inlay restoration from the hybrid ceramic VITA ENAMIC Gerhard Werling

42 Clinical 42

Minimally invasive veneer restoration with ceramic-based restorative material Mauricio Watanabe

50 Clinical Evaluating the fit of removable dentures with magnification systems Gualtiero Mandelli and Carlo Borromeo

62 Products

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Community Outreach Dental Program Henry Schein Halas was proud once again to host the Community Outreach Dental Programs (CODP) charity auction dinner. Their major fundraising event for the year, the dinner allows CODP at Common Ground to continue the work they do servicing the community of Adelaide who otherwise would not have access to dental care.

The picturesque back drop of the Adelaide Oval ensured the perfect evening with Cosi (Andrew Costello) from South Aussie with Cosi adding some extra zing to the evening! The Executive Dean of Health Science’s at Adelaide University, Professor Alastair Burt welcomed everyone to the event and thanked Henry Schein Halas and the Henry Schein Cares Foundation for their continued support, however it was Dr Karen Hawke’s story that stole the show. Dr Hawke shared with the audience her tough upbringing which lead to a life of drug addiction and limited future prospects. Against all odds she changed her life around, not only getting clean and obtaining an education but raising a child as well. She told of her time living at the Common Ground Facility and how the availability of dental treatment through CODP helped her along the way to keep on track. Stories just like this one are why Henry Schein Cares happily support CODP. Bronte Manuel Golden Gravel Award winning auctioneer from Toop and Toop encouraged all guests to dig deep during the major auction with all items selling including 2 paintings donated by Dr Geoff Heithersay. The paintings by Dr Harold Austin (one an Aboriginal style painting Ngarrindjeri Dreaming and the other Compassion depicted an abstract of caring in the dental setting) were purchased by the ADA. CODP were so grateful for their support and the support of the entire room.

Continuing the dental flavour were band Fang Coup who are a dental band made up of Don Wilson, Tony Bennet and Tony Hooi. They encouraged everyone to get up and dance by starting the night off with the Henry Schein Halas team as backup singers. Luckily for everyone, their microphones had the volume on low!

Community Outreach Dental Program are grateful for the support they receive from the entire community, without this support they would not be able to continue the work that they do. Money raised on the evening will ensure their doors stay open for the remainder of 2017. If you would like to contribute or find out more about Henry Schein Cares activities please email scheincares@henryschein.com.au

Vol. 12 No. 2 ISSN 2071-7962 PUBLISHING EDITOR Ursula Jenkins

EDITOR-IN-CHIEF Prof Dr Marco Ferrari

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

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

Dr Karen Hawke with Andrew “Cosi” Costello.

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

© COPYRIGHT All rights reserved.

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

Published in association with

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CASE REPORT

Aesthetic rehabilitation and tissue preservation in the anterior region Jan-Frederik Güth1 and Hans-Jürgen Stecher2

While there are often several adequate prosthetic treatment options to choose from for one single case, there are some cases where none of the proven solutions seems to be perfectly suitable. The prosthodontist and his team have to balance the pros and cons for each available option – they have to decide which treatment is best suited to fulfil the needs of the specific patient. This was the case with a 16-year-old female patient who presented at the Department of Prosthodontics of the Ludwig Maximilians University of Munich, Germany, in 2015. An orthodontic treatment had just been completed and a further prosthetic rehabilitation was required.

Background At the age of 10, the patient had suffered an anterior tooth trauma with avulsion and replantation of the maxillary central incisors (teeth 11 and 21, FDI notation). Despite all efforts, it had not been possible to preserve tooth 21. The former dentist had replaced it with a four-unit metal-ceramic adhesive bridge (Maryland bridge) (Figs. 1 & 2).

Unfortunately, the dismal prognosis for tooth 11 was confirmed in the course of treatment: it had to be extracted during orthodontic therapy. In order to replace both central incisors for the duration of this therapy, a provisional bridge with artificial gingiva was manufactured and attached to the fixed orthodontic appliances (Fig. 3).

1

1

Dr Jan-Frederik Güth, PD

Jan_Frederik.Gueth@med.uni-muenchen.de 2

Hans-Jürgen Stecher, MDT info@stecher-zahntechnik.de

3

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2 Fig. 1: Situation prior to the orthodontic treatment with an adhesive bridge used to replace tooth 21.

Fig. 2: The adhesive bridge shows a compromised fit after repeated removal and placement.

Fig. 3: Snapshot during orthodontic treatment with temporarily replaced central incisors.

(Image 1–3 courtesy of Prof. A. Wichelhaus)

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CASE REPORT

Fig. 4: Situation at the first visit of the young female patient at the LMU Munich private dental office.

Fig. 5: Patient with interim prosthesis after removal of the orthodontic appliances, replacement of the fillings and palatal tooth preparation.

First steps

Fig. 6: Computer-aided framework design starting from the anatomical tooth vshapes using the Zfx CAD Software.

After removal of the fixed orthodontic appliances, the direct restorations of the maxillary lateral incisors were replaced by new composite restorations. Tooth preparation had already been carried out on these teeth to place the former metalceramic bridge. Hence, it was not necessary to remove large amounts of additional tooth structure, however, the existing palatal preparations required refinement. Subsequently, gingiva management was carried out with retraction paste.

An impression was taken with the 3M True Definition Scanner and uploaded to the 3M Connection Center. The patient received a removable interim prosthesis (Fig. 5).

Prosthetic treatment plant At the patient’s first visit in the private dental office of the LMU Munich, the lateral incisors had large composite restorations not only on the vestibular surfaces, but – due to the previous rehabilitation with an adhesive bridge – also on the palatal surfaces (Fig. 4).

Tooth 22 had received an endodontic treatment. This fact significantly limited the prosthetic options and had a negative effect on the prognosis of this tooth. The developmental stage of the cervical vertebrae assessed by the orthodontist using lateral cephalometric radiographs revealed that only minimal transversal and horizontal growth was still to be expected for this patient. Due to this fact and the unfavourable prosthetic value of the abutment teeth, the prosthodontic team – in consultation with the patient—decided to place an all-ceramic adhesive bridge with two wings bonded to teeth 12 and 22. The aim of this treatment was to postpone the placement of implants as long as possible in order to ensure that the patient was fully grown when this intervention was carried out. By use of a fixed restoration, the team strived for the best possible support and preservation of the surrounding soft and hard tissues.

Laboratory procedure In the dental laboratory, the digital impression file was downloaded, a physical model ordered and the data set imported into the Zfx CAD Software for the design of the adhesive bridge framework. The bridge was designed in full contour. The recommended parameters (minimum wall thickness, connector strength etc.) for the selected material – 3M Lava Plus High-Translucency Zirconia – were entered into the software. Then, the bridge was automatically reduced to the framework (Fig. 6).

This procedure is beneficial in that it provides for a uniform strength and optimal support of the veneering porcelain. The framework was milled, thinned out at the margins using a fine diamond rubber polisher, individualised with dyeing liquids, and sintered. The precise fit of the wings to the palatal tooth surfaces was confirmed on the model before the porcelain layering was performed (Fig. 7). Figure 8 shows the situation at the biscuit-bake try-in.

Finally, the adhesive bridge was finished and glazed. On the model, a highly accurate fit was obtained (Fig. 9), and

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G Ü T H / S T E C H E R

Fig. 7: Precise fit of the sintered framework.

Fig. 8: Try-in of the restoration in its fired, unglazed state.

Fig. 9: Precise fit of the wings in the palatal area.

Fig. 10: Final restoration on the model: A natural colour gradient is obtained.

the restoration showed a natural appearance (Fig. 10). This is in part due to the high translucency of the framework material (Fig. 11).

With the use of a GC Fit Checker Advanced Blue (GC Europe), the precise fit observed on the model was confirmed intraorally (Fig. 12).

As the patient was also satisfied with the aesthetic result, the adhesive bridge could be placed immediately. For this purpose, the working field was isolated with rubber dam and a 37 % phosphoric acid etching gel applied to the palatal enamel surfaces of both lateral incisors for 30 seconds and to

the dentine surfaces for 15 seconds before being rinsed off.

The inner surfaces of the wings were conditioned to increase the surface roughness. After thorough cleaning of the surfaces, an adhesive (3M Scotchbond Universal Adhesive) was applied, rubbed in, air-dried and light-cured according to the manufacturer’s instructions.

Then, 3M RelyX Ultimate Adhesive Resin Cement was applied and the bridge placed. The excess cement was removed immediately with a sponge pellet. To prevent a reaction of the uncured cement with oxygen and lay the foundation for a good marginal integrity, the exposed margins were covered with glycerine gel (Fig. 13) and polymerised.

Figure 14 shows the situation immediately after curing.

Fig. 11: Light transmission through the translucent framework material.

Fig. 12: Use of fit checker to verify the precise fit of the restoration.

Clinical procedure

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G Ü T H / S T E C H E R

Fig. 13: Interfaces between tooth and restoration covered with glycerine gel.

Fig. 14: Margins immediately after curing of the cement.

Fig. 15: Aesthetically satisfying situation after eight weeks.

Further recovery of the gingival tissues needs more time.

Fig. 16: A natural look is obtained.

Result

With regard to the restoration that was produced, the invasive preparation is surely a matter of debate. However, the existing preparation for the metal-ceramic bridge and the large composite restorations limited the amount of sound tooth structure that needed to be sacrificed at this point of the treatment to a minimum, so that the plan became acceptable. In general, the maximum preservation of tooth structure should always be given highest priority when a dental restoration is planned. Important criteria guiding the amount of hard tissue removal are the available intermaxillary space and the minimum wall thickness of the selected material.

Due to the material selection in the present case, it is not necessary to remove the restoration as long as it serves its purpose. Thus, the planned long-term temporary might even become a definitive restoration over time. This, of course, is only possible with continuous monitoring and good compliance of the patient

The aesthetic appearance was already satisfactory, although the harmony was impaired by black triangles between the teeth. Due to the favourable characteristics of the ceramic, however, the soft tissue recovered quickly and closed the gaps. Figures 15 and 16 show the results eight weeks after the restorative procedure.

Discussion As an alternative to the selected treatment option, it would have been possible to place a removable partial denture or two two-unit adhesive bridges with one wing each. The former, however, is regarded as functionally less effective and not capable of supporting the preservation of soft and hard tissues. The two-unit adhesive bridges would have required stabilisation with a retainer. The main reason to opt against this alternative was the compromised value of the abutment tooth 22. As the root surfaces of the maxillary lateral incisors are small, it also seems questionable if this design would have offered sufficient stability to ensure the desired result.

Reprinted with permission by CAD/CAM 01/2017 First publication: 3M™ Health Care Academy Espertise™ Magazine nr.29, edition November 2016 p.28-31.

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CLINICAL

A minimally invasive approach to brown and white lesion removal Luke Hutchings1

Luke Hutchings presents his winning tooth whitening case from the Aesthetic Dentistry Awards 2016.

The patient presented at the practice, unhappy that her teeth didn’t match as they were all different colours – she had obvious white and brown marks, which she disliked.

She had seen two previous dentists for an opinion, so attended my surgery to discuss veneers, as she felt this was the only option for cosmetic improvement.

Clinical presentation The patient presented with a moderately restored dentition; she had no carious teeth and no periodontal concerns. Radiographic examination showed endodontic treatment evident in the UL3; this was well condensed and of good length and no apical pathology was noted.

Aesthetic evaluation showed mild anterior segment crowding and an acceptable smile line, with a reasonable midline and good incisor display. There were uneven gingival levels, especially associated with the UL3, which exhibited recession. A black triangle was present between UR1 and UL1, and UL3 and UL1 were both darker – UL3 as it was non-vital; UL1 proved to be vital on testing with an electric pulp test. Finally, mild fluorosis was evident with white patches UR1/UL1, and a brown spot, likely post-eruptive from extrinsic staining UL1 (Watts and Addy, 2001).

Treatment discussion The patient’s complaint was about the colour of her teeth, so I discussed the option of trying to improve this in a minimally invasive way through the means of tooth whitening.

Discussion followed that if she still wasn’t happy with the improvement after whitening then we could consider a number of different options to remove the white or brown lesions if they were still present: micro/macro abrasion, resin infiltration (Icon, DMG), composite bonding or veneers. The patient felt happy to proceed with the whitening using a progressive smile design methodology.

1

Dr Luke Hutchings BDS Private Practice, Alresford and Twyford Dental Care, UK

Figure 1: Pre-treatment anterior smile view.

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Figure 2: Pre-treatment close-up anterior view.

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CLINICAL

Figure 3: UL1 matched to Vita shade A3.5 pre-treatment.

Figure 4: UR1 matched to Vita shade A3 pre-treatment.

I felt a combination of whitening techniques would be required to achieve an acceptable outcome for the patient, due to the non-vital UL3 and the lower value vital UL1. The process was complicated somewhat as the upper premolars were crowned with existing porcelain-fused-to metal crowns and the patient hadn’t budgeted to replace these, so we wanted to attempt to whiten – but not to a point at which it made these more obvious.

We discussed the options to whiten and we decided we needed to carry out inside-out whitening on the UL3 (first described by Settembrini et al, 1997), some conventional tray whitening to the rest of the teeth and also some single tooth isolated whitening to the UL1.

Warnings were given that although it was likely the brown spot would be removed (Greenwall, 2001), it was unlikely the white spot would. In fact, we warned they would likely look worse before they improved as the white spots dehydrated – once rehydrated it would be likely they would look better as the contrast between the spots and the increased value tooth would be less.

The patient was then instructed on the use of the trays and the careful placement of 6% hydrogen peroxide into the access cavity and into the buccal reservoir of the UL3. This was also marked on the facial surface of the tray in marker to facilitate easy placement for the patient. The patient was instructed to replenish this gel every hour on the hour (Poyser et al, 2004). Careful demonstration and hygiene advice was given about how to clean the access cavity between applications using a Tepe brush and monoject syringe and water. The patient was also given a syringe of 10% carbamide peroxide to apply for nocturnal usage under the same guidelines.

The patient was reviewed after four days and the UL3 was whitened sufficiently. At this point, the access cavity in the UL3 was temporised with glass ionomer to allow for rehydration, thus allowing improved hybridisation of the resin definitive restoration. A period of two weeks is normally suggested after whitening has stopped to allow for better shade match, as there is evidence to show significant shade change in this two-week period (Deliperi, 2008).

The patient was then instructed to use the same whitening trays for two weeks of usage with 10% carbamide peroxide for nocturnal usage. Carbamide peroxide releases hydrogen peroxide slowly, so wear for at least four to eight hours is recommended, hence it is more suited for use at night time.

Again, careful instruction in usage and hygiene were given.

Treatment At the initial treatment visit, upper and lower two-stage putty and wash silicone impressions (Aquasil Ultra, Dentsply) were taken with a foam spacer. These were then sent to the laboratory with instructions to make super-sealed whitening trays.

The return visit was deliberately set on Friday morning, as inside-out whitening very much relies on patient compliance and the patient felt this would be easier to achieve over a long weekend. Whitening trays were checked for fit. The access cavity in the UL3 was opened and care was taken to remove all remnants of the coronal resin-based restoration. Gutta percha was then removed to 1mm below the amelocemental junction and the gutta percha was sealed with glass ionomer.

Post-treatment review The patient returned for subsequent review, happy with the overall match and shade of her teeth but felt the UL1 was still slightly lower in value than her surrounding teeth.

A single tooth whitening tray had been fabricated for this eventuality. Essentially, this is a super-sealed tray with the adjacent teeth removed to allow excess gel to be removed

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HUTCHINGS

Figure 5: Pre-treatment left lateral smile view.

Figure 6: Pre-treatment close-up left lateral view.

Figure 7: Pre-treatment right lateral smile view.

Figure 8: Pre-treatment close-up right lateral view.

Figure 9: Situation following whitening.

and not affect these teeth; hence over-whitening them. At a final whitening review, the patient was delighted with the whitening result and the brown spots had been removed well.

However, the patient felt after going through the trouble of getting the whitening right she would like to explore the option of white spot removal.

Treatment modalities discussed were minimally invasive, as at this point the patient felt happy with her smile aesthetics and had moved away from her original thoughts of laminate veneers. Options discussed were microabrasion or resin infiltration technique (Icon, DMG); the patient felt happy with Icon treatment.

Icon is a resin infiltration system originally designed for minimally invasive restoration of interproximal cavities. It consists of Icon Etch (hydrochloric acid, silicic acid), Icon Dry (99% ethanol) and Icon infiltrant (methacrylate-based resin).

Icon has been shown to have some promising result in masking white spot on smooth surfaces of teeth (Munoz et al, 2013); it achieves this by mimicking the natural refraction index of enamel, hence disguising the lesion. The technique steps are as follows:

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HUTCHINGS

Figure 10: Post-treatment anterior smile view.

Figure 11: Post-treatment left lateral smile view.

Figure 12: Post-treatment right lateral smile view.

Figure 13: Post-treatment anterior view in occlusion.

Figure 14: Post-treatment left lateral view in occlusion.

Figure 15: Post-treatment right lateral view in occlusion .

1. Thoroughly clean the surface and place rubber dam 2. Icon etch application for two minutes 3. Rinse and air dry with suction 4. Apply Icon dry to preview the effect 5. Repeat steps three and four as required – the patient required five cycles before the white spots were masked 6. Apply Icon infilitrant, allowing to set for three minutes 7. Remove excess with floss and cotton wool roll. Light cure for 40 seconds 8. Repeat steps six and seven 9. Polish with rubber point for surface polish.

Reflection The patient was delighted with the outcome and I am pleased with the overall aesthetic appearance. I feel that the shade of the teeth is much more consistent in the smile display. I am really pleased with the minimally invasive nature of the treatment, especially given that the patient attended requesting veneers.

Areas I could improve, and will probably do when I next see the patient, is improvement to the facial polish after the Icon treatment, as the 1:1.5 view shows a little bit of incorrect texture.

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HUTCHINGS

Figure 16: Post-treatment anterior view.

Figure 17: Post-treatment left lateral open view.

Figure 18: Post-treatment right lateral open view.

Figure 19: Post-treatment close-up view.

Figure 20: Post-treatment close-up left lateral view.

Figure 21: Post-treatment close-up right lateral view.

References

Poyser NJ, Kelleher, MG, Briggs PF (2004) Managing discoloured non-vital teeth: the inside/out bleaching technique.

Dent Update 31(4): 204-201, 213-214 Settembrini L, Gultz J, Kaim J, Scherer W (1997) A technique for bleaching nonvital teeth: inside/outside bleaching. J Am Dent Assoc 128(9): 1283-1284 Watts A, Addy M (2001) Tooth discolouration and staining: a review of the literature. Br Dent J 190(6): 309-316

Deliperi S (2008) Clinical evaluation of non-vital tooth whitening and composite resin restorations: five-year results. Eur J Esthet Dent 3(2): 148-159 Greenwall L (2001) Bleaching techniques in restorative dentistry: an illustrated guide. Martin Dunitz, London Munoz MA, Aran-Gordillo LA, Gomes GM, Gomes OM, Bombarda NH, Reis A, Loguercio AD (2013) Alternative esthetic management of fluorosis and hypoplasia stains: blending effect obtained with resininfiltration techniques. J Esthet Restor Dent 25(1): 32-39

Reprinted with permission by Aesthetic Dentistry Today February 2017

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CASE REPORT

Lisi Press monolithic crowns Karyn M. Halpern1 and Bill Marais2

Case background – Lisa

1

Karyn M. Halpern DMD, MS Case study and technique

2

Bill Marais Laboratory technician

Lisa was referred to my practice by my office manager Michele. She was very nervous, having not been to a dentist in many years, and described having poor experiences with her previous dentist.

Lisa was 49 years old at the time and otherwise healthy. Her initial clinical and radiographic examination revealed that every tooth in her mouth was in need of some sort of restorative treatment.

It was determined the etiology of Lisa’s caries and periodontal disease was a combination of a history of eating candy daily, occasional smoking, poor oral hygiene, and iatrogenic dentistry.

Fortunately for Lisa, she was not in any pain or discomfort. This allowed for us to prioritise her treatment and develop a plan that could be executed in stages using a team approach amongst the periodontist, endodontist, hygienist, lab technician and myself.

Lisa’s treatment began with a full mouth debridement and referral to our periodontist.

The periodontist performed extractions and socket preservation of hopeless retained roots #’s 14 & 30. Removal of failing ill-fitting PFM crowns with severe recurrent decay on teeth #’s 15, 19, & 31 was completed and milled nano ceramic resin crowns were placed as long term provisionals. The endodontist then completed root canal retreatments on both #’s 19 & 30.

Lisa was educated on proper diet, hygiene, and placed on Carifree toothpaste and CTX3 rinse. She then underwent full mouth scaling and root planing therapy. She was educated on the importance of prevention and maintenance.

After seeing much improvement in her hygiene and periodontal health, it was decided to proceed with creating our blueprint for her full mouth rehabilitation. This was achieved with diagnostic impressions, diagnostic photos, occlusal analysis of mounted casts, and completion of full mouth diagnostic wax up of all teeth to receive indirect restorations.

After consulting with Lisa, it was decided to proceed with the next phase of restoring her maxillary arch with all ceramic crowns.

Lisa’s maxillary anterior teeth had a history of a mosaic of multiple failing resin fillings per tooth as well as root canal treatments on teeth #’s 7,8 & 9.

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CASE REPORT

Figure 1. Before.

Figure 2. Diagnostic wax up.

Figure 3. Diagnostic wax up.

Figure 4. Bite registration

Figure 5. Final PVS impression.

Figure 6. Stump shade selection.

She presented for excavation, preparation, core build ups, and provisionalisation of teeth #’s 3–13 without complaints.

Upon removal of failing resin restorations and recurrent caries on teeth #’s 7,8 & 9, it was discovered that cotton pellets were left under the existing resin restorations. The caries extended into the pulp chamber and a foul odour was expressed upon removal. Lisa was advised of the findings and referred to the endodontist for the retreatment of root canals on teeth #’s 7,8 & 9 prior to final crowns delivery.

Technique Diagnostic impressions and photos were taken and sent to my technician Bill Marais for a full mouth diagnostic wax up.

All pre-existing composite and amalgam restorations were removed and all caries excavated. Core buildups were completed with a combination of direct composite on the anterior preps and core paste on the posterior teeth.

A gingivectomy was performed using a diode laser on teeth #’s 8 & 10 to correct her gingival asymmetries and

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HALPERN / MARAIS

Figure 7. Preparations with core build up and gingivectomy.

Figure 8. Temporisation with GC Tempsmart.

Figure 9. Temporaries.

Figure 10. Removal of temporaries.

Figure 11. Cleaning preparations with pumice.

Figure 12. Try in.

mimic the diagnostic wax up.

The VDO was recorded and maintained using a PVS bite shim that was relined in sections using PVS bite registration material.

A final PVS impression was taken using a single cord technique and a combination of light and heavy body materials, a habitual PVS bite registration, and bite registration with a Kois dental facial analyser.

Photos of the preparations against chosen shade tabs were taken for the technician to evaluate the prep shades.

Provisionals were fabricated using GC Tempsmart™

injection technique into the putty index of the diagnostic wax up. The gingival embrasures were left widened in the provisionals to allow for proper hygiene and prevent gingival inflammation.

Provisionals were cemented with translucent provisional resin cement in 3 segments: #’s 3–6, 7–10, 11–13.

Photos were taken of the provisionals and sent to the lab technician.

The lab technician fabricated LiSi Press monolithic crowns with GC lustre paste stain & glaze for teeth #’s 3, 4, 5, 6, 11, 12, 13 and Lisi Press layered crowns with GC Initial™

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HALPERN / MARAIS

Figure 13. Cleaning final restorations.

Figure 14. Cementation, removing excess cement.

Figure 15. Final, front view.

Figure 16. Final, side view.

LiSi ceramic on #’s 7, 8, 9, 10.

The patient returned for delivery of the final restorations. The provisionals were removed. The crowns were tried in individually and then together to check marginal fit and contacts.

The teeth were then prepared for total adhesive bonding : pumice, 4% chlorohexidine scrub, gluma placed on vital preps.

The teeth were isolated with both an optragate and Teflon tape. The crowns were treated with ivoclean and bonding

adhesive. The crowns were then seated two at a time starting with the centrals and moving distally.

Care was taken to remove all of the excess resin cement and the occlusion was then adjusted and verified in centric and excursions.

Reprinted with permission by GC Australasia Dental Pty Ltd Copyright © 2017

17

18

Figure 17. Before.

Figure 18. After.

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CLINICAL

Direct restorations: the last 10 years Andrew Chandrapal1

The notion of recreating the natural form of teeth was once a technique and art form left to those at the very top of the ‘direct restorative food chain’. Some of these individuals remain at the forefront of inspirational dentistry and display their work around the globe.

For those of us mere mortals who practise everyday general dentistry and in particular direct restorations, the main focus has remained to take the patient through a comfortable and clinically suitable journey to improving their dental health, using one or several materials available on the professional commercial market.

If the last 10 years has taught us anything, it is that the general practitioner is able to practise excellence in direct restorative dentistry, enabling natural yet functional outcomes that are not only representative of the natural tooth form but also attempting to conserve as much tooth tissue as possible.

In other words, the last 10 years has given the general dentist the opportunity to recreate the natural dentition and not just a ‘filling’.

Composite resin – material changes over the last 10 years

1

Andrew Chandrapal BDS MFGDP(UK) DPDS(Bris) MClinDent (Pros) Private Practice, London, UK

Composites, by definition, are simply ‘the combination of several parts or elements’.

The adaptation of filler particles, monomers, photoinitiators, and coupling agents has changed hugely over the past 10 years. Filler particle size has changed from hybrid to nano and even micro particles. In real terms, 1µm particles have reduced to 0.04µm, as a direct comparison. This, as well as filler volume variation, has created improved hand fling, better aesthetics, greater fracture resistance and improved polish retention within the oral environment.

The direct result of this is the fact we now apply composite resin to more clinical applications than we ever thought possible. Figure 1 illustrates the natural and harmonious results obtained using composite for direct veneers. Although the recall is only at one year, it shows how well the material is able to support and mimic the surrounding dentition using no preparation techniques.

It is now possible to conduct full mouth rehabilitations using direct composite resin to very good levels of predictability. Following on from this, it has enabled our dentistry to become far less invasive to the tooth substance than previous versions of the material.

In the right circumstances, prep-less dentistry is possible using modern composites that have improved wear properties and aesthetic qualities.

Obtaining suitable combinations of varying nano filler size with filler weight has enabled the industry to create strong yet highly polishable materials that are suitable for both anterior and posterior dentition.

Now that such materials are available, the key is learning how to use them in such a way to obtain optimal results. This means learning how to handle, manipulate, layer, finish, and polish the material.

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CLINICAL

Figure 1: 12-month recall on upper central composite veneers.

Figure 2: LM Arte Misura, courtesy of Styleitaliano.

Most composite systems on the modern-day market will allow decent restorations when handled correctly. The most experienced clinicians will know the materials so well they will be able to combine various systems together to obtain a true representation of the surrounding natural anatomy.

restoration. In short, the process for instrument application over the last 10 years has reduced in need, although new instruments that have emerged in response to a greater understanding of composite resin.

Hand instruments

Photography – our opportunity to scrutinise to the next level

In 1994, Dr Nitzan Bichacho suggested the idea that the various hand instruments used to manipulate direct restorations were unnecessary (Bichacho, 1994). With regards to composite materials, the industry has almost gone full circle in the last 10 years. Elaborate instrument sets were – and still are – available to enable the clinician to handle the material and apply it in an anatomical fashion.

We have learned over the last 10 years that this in fact is not needed and thus refer back to the work of Dr Bichacho of more 20 years ago, which suggested the mode of application of composite increments using a probe and manipulating this increment to its desired position using high quality micro brushes. This not only reduces the complexity of instruments being used, it also enables complete control of polymerisation contractile forces causing unwanted flexure upon curing.

In more recent years, certain instruments have emerged that aim to assist in the layering process of enamel and dentinal composites. Given the fact the refractive index of enamel composites is generally greater than that of natural enamel, the final enamel layer tends to be thinner than the natural tissue would otherwise be.

LM Arte has created the Misura instrument, shown in Figure 2, which highlights 0.5mm thickness of material so as to ensure over-conturing does not take place, as well as obtaining an even thickness over the horizontal profile of the

Clinical photography has improved in leaps and bounds over the last 10 years. Cameras are now more sensitive, and lighting systems are now more readily available. The ability to use twin versus ring flash systems enable us to evaluate the natural form and end restoration with confidence. It remains essential to utilise clinical photography to document and plan the direct restoration to maximal extent.

Use of photographical aids, such as contrasters, have also aided the clinician in terms of incisal edge anatomy, translucency, dentinal mammelon structure and distribution, and primary, secondary and tertiary anatomical features.

Figure 3 shows a range of natural features that can be used when direct composite can not only include such high features, but be applied in a conservative manner, and thereby not adding to the tooth tissue loss that has already occurred. Such skills can also highlight the nature and extent of developmental white and brown spots on teeth so that they can either be removed or incorporated within the restoration.

The explosion of dental clinical photography has aided the clinician greatly. In reference to direct resin dentistry, it has enabled us to plan our restorations by taking a series of clinical shots using a few aids such as retractors and contrasters to highlight the detail in the natural form, as well as anatomical feature and morphology.

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C H A N D R A PA L

Figure 3: Preoperative records to illustrate tooth surface loss.

Once again, the last 10 years have given the clinician a gentle push to be educated within the field of photography, given the availability and importance of clinical documentation.

Curing lights Curing lights have moved away from halogen and towards LED, which is now the mainstay of direct and indirect adhesive dentistry. This means a more constant wavelength with no variability of curing ability and loss of power that can happen with an expiring halogen bulb. This has meant light curing units are smaller, which equates to easier placement towards the posterior teeth as well as fewer components, such as fans for cooling.

Within the last 10 years we have seen a reduction in the use of plasma curing lights that made the claim to being able to polymerise composite resin within a matter of a few seconds. We now know that depth of cure varies dependant on the opacity and bulk of increment being placed, as well as reflection of the increment also having a bearing.

Angle, rate and intensity of cure have been shown to matter (Price et al, 2015). In short, whilst LED lights now offer this, plasma lights are now all but redundant as it has been shown that polymerisation rates cannot be guaranteed using such short curing cycles. The principles of light curing have thus remained to be the same, as the industry appears to have gone full circle in an effort to bring the clinician more efficient methods of curing.

Shade taking Matching the natural dentition remains at times to be a demanding and time consuming process, which can be fraught with error and mis-judgement. The notion that single layer (monochromatic) composites can be used to mimic the natural dentition simply cannot be achieved with predictability.

Consequently, we now have greater understanding of shade and some aids that have been designed within the last 10 years. Certain photographic filters, such as cross-polarisation, have enabled the clinician to eliminate spectral reflection, thus effectively highlighting the internal anatomy of teeth.

This has been influential in terms of dentinal mammelon distribution and inclusion of intensive features such as white spots. Such filters are now widely available and can even be homemade, but allow greater depth of observation to enable more features to be included within direct restorations.

Historically the industry has relied upon Vita shade guides to determine the overall shade of teeth. Vita 3D guides have moved us one step further on in terms of value and chroma determination.

However, the notion that acrylic can mimic the restorative material used at that time has remained to be incorrect.

As such, the last 10 years have given us the ability to use prefabricated or custom shade guides that are made from the direct restorative material being used at that time. This gives us the closest reference possible in terms of the materials being used.

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C H A N D R A PA L

4

5

Figure 4 and 5: Composite shade tabs illustrating enamel and dentine alongside the combination of the two for true comparison (Inspiro – Optident).

It is essential that the clinician ensures the composite system being used has its own shade guide constructed of the resin material and not acrylic. Such guides are now also available in an outer shell of enamel and internal dentine to give combination effects to mimic the effect of layering two specific shades together.

The last 10 years have empowered the clinician to think more laterally about the tissues he/she is attempting to reproduce. As such, the industry has responded by constructing shade guides that are now designed to mimic the layers, rather than a Vita acrylic block that can at times lead us to incorrect results.

Figures 4 and 5 illustrate such an example of composite resin shade tabs arranged in enamel and dentine, but also allowing the combination of the two. Such resources have really changed the way the clinician is able to perceive the desired shade.

Empirical longevity studies As with most forms of clinical and academic dentistry, we now have more clinical research to be suggestive of greater success rates using direct materials. This is in part due to an improvement in the materials, but also techniques of isolation, bonding protocols and being more aware of the limitations.

Academics such as Jürgen Manhart and Didier Dietschi have been pivotal in providing the clinician with valuable data to suggest our methods of direct resin restorations are showing promise, not only in the short term, but anything up to 25 years of data have now been produced to support such techniques (Hickel et al, 2000).

It is important that clinicians make themselves familiar with such research to support their techniques and update them

accordingly. However, the current stance is that using strict isolation and bonding protocols, direct resin restorations are being shown to have very good longevity – albeit remaining sensitive to clinical technique.

Tooth preservation The strive to become ever more conservative within the last 10 years has spearheaded the need for direct resin restorations to have a resurgence within the dental market.

Organisations such as the British Academy of Cosmetic Dentistry have been widely promoting, where possible, minimally invasive dentistry to create lifelike results with everimproving longevity.

This results in dentistry that is both appealing, and costeffective to the patient, as well as generally safer methods of application when compared to aggressive preparations that are related to indirect techniques.

With this said, it remains the clinician’s level of experience and expertise that must make the correct judgement as to what will obtain the best result in the interest of the patient for short and long terms time spans.

CAD/CAM hybrid composites The drive to make clinical dentistry more digital has led to the industry producing hybrid composites that are effectively machined within our own surgical environments using CAD/CAM technology. The last 10 years have vastly improved in terms of scanning technology and thus the use of hybrid composite, often containing ceramic fillers to be used in clinician scenarios where perhaps indirect restorations that were lab based were being utilised.

The discussion as to whether such resins remain to be truly

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direct or indirect continues; however, the last 10 years have empowered the clinician to at least offer this service, as well as accuracy of intraoral scanners increasing hugely. This means a shift of thinking for the clinician but for some has changed the way they practice dentistry.

Conclusions Ten years in science and research can be seen to be a long time. It is clear things have changed; by using modern direct composite materials we are now able to be more predictable and have greater longevity with a wider remit of treatment modalities. It is fair to say that further research is always the key and that the industry will not always produce products and materials that are truly beneficial to the clinician and patient; however, adhering to strict isolation and bonding protocols and lateral thinking on clinical decisions and treatment planning can greatly improve outcomes.

Modern materials and techniques have so far taken us a long way and will continue to do so for at least the next 10 years.

References Bichacho N (1994) The centripetal build-up for composite resin posterior restorations. Pract Periodontics Aethet Dent 6(3): 17-24 Hickel R, Manhart J, Garcia-Godoy F (2000) Clinical results and new developments of direct posterior restorations Am J Dent 13(Spec No): 41D-54D Price RB, Ferracane JL, Shortall AC (2015) Light-curing units: a review of what we need to know. J Dent Res 94(9): 1179-1186 Reprinted with permission by Aesthetic Dentistry Today February 2017

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SCIENTIFIC

Thermal damage behaviour of human dental pulp stem cells Karsten König1 and Anton Kasenbacher2

Objective This study was designed to examine the influence of temperatures ranging from 37 to 65 °C on the cell morphology of DPSC stem cells via light and electron microscopy, a synthesis of Heat Shock Proteins (HSP) with fluorescence-marked antibodies and vitality using the Live/Dead Fluorescence Kit.

Material and methods

1

Prof. Dr Karsten König Saarland University Campus A5.1, Room 2.35 66123 Saarbrücken, Germany Tel.: +49 681 3023451 Fax: +49 681 3023090 k.koenig@blt.uni-saarland.de

2

Dr Anton Kasenbacher Private Practice, Obere Hammerstr. 5 83278 Traunstein, Germany Tel.: +49 861 4692 Fax: +49 861 12853 a.k@ts-net.de

DPCS were cultivated at 37 °C and 5 % CO2 in sterile cell chambers (MiniCeM, JenLab GmbH, Jena, Germany). The cells were irrigated with pre-heated culture medium (Eagle’s MEM, Gibco BRL, Paisley, Scotland, 37 °C) with 20 % FCS, 2 mM L-Glutamin and 100 µM L-Ascorbate-2-Phosphate in order to re-move cellular debris previously to the temperature trials. Filling the chamber with the culture medium followed and a preheated water bath of different temperatures was introduced. Up to an incubation temperature of 46 °C, the experiments were con-ducted with temperatures rising every 2 °C and 0.5 °C in the sensitive temperature scale of 46 °C to 58 °C. In addition, trial series were carried out at 60 °C and 65 °C. After a total of 15 min of thermal treatment, the cells were cooled down in the incubator at a temperature of 37 °C for 1 hour.

Some of the cells which had undergone thermal treatment were examined with the Live/Dead Fluorescence Assay (Molecular Probes, Eugene, OR, USA) in order to assess vitality via fluorescence microscopy and Axiovert 200 (ZEISS, Jena) after incubation. A mixture of 2 µM Calcein AM and 4 µM Ethidium- homodimer-D1 was added to the cells which were slowly cooling down at 37°C in the incubator either 1 h or 24 h after thermal treatment and incubated for 10'. Vital cells exhibited a green fluorescence caused by calcein, while lethal cells showed a red core fluorescence (Ethidiumhomodimer-D1 and coupled DNA). 100 cells of each type were enumerated.

In order to examine the synthesis of HSP proteins, the cells having undergone thermal treatment were processed as follows: - Opening of the chamber and removal of the cover-slip containing the cells - Suction of the nutritive medium, two rinses with PBS (isotonic: 67 mM phosphate buffer pH 7.2–7.4, 0.5 % NaCl) - 12' fixation in 2 % paraformaldehyde in 0.1 M cacodylate buffer pH 7.2; Rinse: 3 x PBS, 2 x TBS (Tris buffered saline, 50 mM Tris-HCl buffer, 1.25 % NaCl) - Parting of the coverslip with Pap-Pen pen (oil pen), possibly correct with paraffin - Incubate one half of the coverslip overnight at 4 °C with 1:500 diluted antibody AK HSP25, Rabbit (Bio-mol), diluting solution: fish gelatin 1 %, Triton x 100 1 % in TBS) - Cover the other half of the coverslip exclusively in diluting solution (without AK) - Wash in TBS for 3 x 10' - 15` Alkaline-Phosphatase verification with 3 mM Levamisol in Chedium (induces bluebrown colouring according to Seidel).

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Table 1: Life/Dead Assay 1 hour and 24 hours after thermal treatment.

Temperature

Vitality %

°C

1h

24 h

37

0

0

39

0

0

42

0

0

45

0

0

46

0,5

2

47

10

17

48.5

18

29

50

17

27

55

24

59

56.5

48

54

58

100

100

60

100

100

65

100

100

Figure 1: Vitality test of thermally treated DPSC.

In order to perform examinations with scanning electron microscope, the cells were processed as follows: - Washing of the cells in cacodylate buffer (0.1 M) - Fixation with 2.5 % Glutaraldehyde in cacodylate buffer for 20' - Washing with cacodylate buffer for two times, followed by two washings with Aqua dest - Dehydration with increasing alcohol concentration: 20 %, 30 %, 50 %, 70 %, 90 %, 2x in 100 %EtOH for 10' each - Further processing of the samples at the Centre for Electron Microscopy (Critical Point Drying and sputtering with gold; SCD 005, BAL TEC AG, Liechtenstein) - Microscope: Zeiss EM 902 A. Examinations with the transmission electron microscope were conducted: - Washing of the cells with cacodylate buffer (0.1 M) with 6.8 % Sucrose - Fixation of 30' with 1 % glutaraldehyde - Washing with cacodylate buffer - Contrasting with 1 % Osmiumtetroxyde and 1 %potassium ferrocyanide for two hours - Dehydration with increasing alcohol concentration: 20 %, 30 %, 50 %, 70 %, 90 %, 2x in 100 %EtOH for 10' each

- Embedding in Epon (epoxy resin), polymerisation for four days at 60 °C - Ultramicrotomy, ultra-thin sections (70 nm; Leica Ultracut S, Leica Mikrosysteme GmbH, Bensheim, Germany) - Dyeing of the sections with 1 % Uranyl acetate in methanol and 1 drop of acetic acid for 10' - Microscope: Zeiss EM 906.

Results Light microscopy and vitality test The cells received thermal treatment at temperatures ranging from 37 °C to 60 °C and varying inter-mediate temperature levels. Light microscopy examinations showed significant morphological changes at temperatures from 46.5 °C ± 0.5 °C. At temperatures from 37 °C to 45 °C, all cells exhibited a green calcein fluorescence. At temperatures of 46 °C and above, lethal results were detected in some of the cells that had undergone thermal treatment. The number of lethal cells increased in correspondence to a rise in temperature.

At temperatures of 46 °C to 56.5 °C, the number of lethal cells had almost doubled 24 h after thermal treatment in comparison to the number of lethal cells one hour after

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microscope or transmission laser microscopy showed a slight, unspecific colouring of the cells after incubation of 37 °C (control, Fig. 2). An increase in HSP production (intense colouring) was noted at a temperature of 50 °C, while thermal treatment at 60 °C again resulted in slight, unspecific colouring of the cells.

REM

Figure 2: HSP-detection caused by an antibody color reaction.

thermal treatment (Table 1, Fig. 1). Starting at 56.5 °C, this phenomenon ceased, with about the same number of lethal cells. This temperature of 56.5 °C corresponded to the LD50 value (50 % lethality). No cell survived thermal treatment at 58 °C.

HSP production Examinations with regard to the production of HSP via light

Scanning electron microscopy showed a typical flat, long distribution of the control cells (37 °C cells, Fig. 3). These cells exhibited many processes and microvilli-like structures.

In addition, cell-to-cell connections with neighbouring cells were observed.

The successive rise in temperature resulted in the first critical temperature level of 46.5 °C ± 0.5 °C. From this level onwards, significant initial changes of the cells were registered via light and electron micro-scope, especially an initial deformation and rounding of the cells. The cell structure (microvilli-like structures) was reduced. However, microvilli were ob-served at temperatures of up to 50 °C (Fig. 4). At 50 °C (chance of survival > 70 °C according to Live/Dead Assay), the cells left distinct cytoplasm protuberances on the base of the coverslip (Fig. 4, arrow), probably caused by a rapid contraction or rounding.

Incubation at a temperature of 60 °C, at which none of the cells survived, resulted in a different outcome. There was no apparent deformation or rounding of the cells, with the original cell shape remaining mostly intact and some small reductions. The cells appeared to have been “thermally fixed” instantly. Neither microvilli nor other surface structures were visible. Cell processes in contact with the coverslip remained intact, but exhibited denaturation and fixation caused by rapid heating (Fig. 5).

Figure 3: Control cells exhibited a normal appearance at 37 °C under REM. Cell processes, microvilli-like structures on the cell surface (their numbers seems to depend on the level of cell activity) as well as the elongated cell shape are clearly visible.

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Figure 4: REM: Thermally treated DPSC showed external signs of cellular damage at 46.5 °C: The cell usually changes its elongated shape and starts to round. At 50 °C, an increased rounding can be observed. The cell seems to contract so fast that a part of the cytoplasm processes tears off (arrows). The surface structure of the cells is effected as appearance and number of microvilli change.

TEM The fibroblast-like DPSC cells (Fig. 6) exhibited long, extended mitochondria (M) within the 3-D network of the cell at 37 °C (control). The nucleus (K) appeared to be undivided and to have a normal nuclear envelope (arrows). ER/RER, free ribosomes as well as the Golgi apparatus did not show any anomalies. A significantly expressed cytoskeleton (Z) whose filaments were aligned parallel to the longitudinal axis (probably microfilaments) was observed. The cells featured a number of inclusions.

At 50 °C, cell rounding became irreversible (Fig. 7).

Mitochondria (M) exhibited structural changes, especially an inflation which concurred with the destruction of the cristae alignment, the parallelism of which got lost. There was no longer a three-dimensional network. The Golgi apparatus was significantly deformed and hardly any vesicles were constricted. The cytoskeleton was partially disintegrated and could no longer be detected. The cell membrane appeared to have increases vacuolisation. The nucleus (K) appeared to be damaged irreversibly. The nuclear envelope was inflated and partially disintegrated (*). The nuclear plasma condensed at the chromatin, resulting in a reduction of the euchromatin-areas which condensed at the heterochromatin.

The nucleus exhibited segmented chambering (arrow).

Contrarily, the external shape of DPSC cells incubated at 60 °C (Fig. 8) remained mostly intact. How-ever, cytoplasm was hardly detectable. Mitochondria (M) were destroyed,

membranes and cristae were partially wound up (arrows).

Golgi apparatus and cytoskeleton were not detected. The euchromatin areas were reduced at the nucleus (K) and condensed at the heterochromatin (*). The nuclear membrane was significantly vesiculated.

Discussion The first indications to a temperature-related damage of the DPSC were seen in the Live/Dead Assay.

Calcein is able to penetrate the membrane and is only converted to a fluorescent colouring agent inside of an intact cell. If the cell membrane becomes permeable as a result of damages, calcein will not remain inside the cell. As a consequence, Ethidium-homodimer-1 will enter the cell in exchange. This substance is not permeable for intact membranes and will fluoresce red when combined with DNA. Interestingly significant thermally-induced dam-ages were only observed at temperatures ranging from 46.5 °C ± 0.5 °C. Starting at this temperature, cell membranes are destroyed apparently. Temperatures from 56.5 °C ± 0.5 °C form another threshold at which the 50 % lethality limit was reached.

If the vitality test was conducted 24 h after thermal treatment, almost twice as much lethal cells as observed 1 h after incubation were seen at temperatures from 46.5 °C to

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Figure 5: REM: Thermal treatment at 60 °C. While the exterior shape remains mostly intact, their surface does not exhibit any structuring anymore.

56.5 °C. It appears that repairing processes cannot eliminate the thermal damage. Contrarily, thermal treatment will result in a lethal reaction even 1 h later.

Starting at 56.5 °C, most cells died immediately, probably due to denaturation of the proteins (coagulation). Usually, a temperature level of 62 °C is given as the starting point for coagulation in the literature.

However, the Live/Dead Assay does not allow any conclusions on the effects of the damages on the cell organelles, compartments or physiological reactions such as protein production. Consequently, HSP tests and electron microscopic examinations of the ultra-structure were conducted additionally.

Heat-Shock-Proteins (HSP) were detected very well at 50 °C by an antibody reaction. The cells were distinctly coloured, which implies a significant reaction of the cell on the temperature-related stress. These cells were still able to synthesise the proteins and to survive for some time. Controls only showed only a light colouring, which may be the result of an unspecific reaction of the antibody with different cell proteins as well as a production of HSP which is not related

to thermal stress.

Similarly, a temperature level of 60 °C only lead to light colouration, which can be explained by the immediate lethal effect resulting in a missing time scale for the biosynthesis of HSP. In general, it should be noted that the first HSP examinations did not exhibit the expected intracellular resolution due to a low specificity.

The results of REM and TEM at the different guide values of 37 °C, 46.5 °C, 50 °C, 60 °C and 65 °C fit very well with the results from light microscopy. The effects of a sudden and massive heating to more than 46 °C on the exterior cell shape (rounding and partial reduction of external structures) are distinctly visible. The extremely fast contraction of the cells at temperatures around 50 °C might result in the observed tearing of cytoplasm-processes. Thermally-related membrane openings were not detected via REM even at temperatures of 60 °C and above. These high temperatures probably resulted in an immediate coagulation of membrane proteins and other intracellular proteins, which lead to a “conservation” or fixation of the cells in their current shape.

While the external cell shape was maintained because of

Figure 6: TEM: Control cells at 37 °C. K: Nucleus; ER: endoplasmatic reticulum, RER: rough endoplasmatic reticulum; M: mitochondria; Z: cytoskeleton; arrows: markers of the nuclear membrane.

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Figure 7: TEM: Due to thermal treatment at 50 °C, the cells are rounded and the cell membrane forms vesicles (left). Mitochondria exhibit a disrupted structure of the christae, while the nuclear plasma starts to condense and the nucleus (K) itself often appears to be uncharacteristically flapped (arrow). The nuclear membrane (*) seems to be partially inflated or dissolved.

the lacking time window for morphological modification, irreversible damage to the organelles, nuclear membranes, nuclei and cytoplasm were detected electron-microscopically.

Starting at a temperature of 46.5 °C, a vacuolated cell membrane was observed via TEM in the rounded cells.

Nucleus, organelles and cytoskeleton were subject to beginning morphological changes.

The cells reacted differently on heating, probably because their differences in physiological age, activity and cycle states influenced immediately visible effects. For example, the cells differed in the level of microvilli reduction.

If the survival of thermally treated cells will prevail for a time span of more than 24 h and if there are thermally-related damages of the reproductive behaviour remains to be

examined by further studies. However, it may be postulated with caution that the presented data indicate a chance of survival of the examined DPSC up to a temperature of 46 °C. These results on the thermal damage behaviour of human dental pulp stem cells are important for the development of ultrashort dental laser systems.

Acknowledgements: The authors would like to thank Dr Walter Richter, Dr Iris Riemann and Mr Helmut Hörig (Clinical Centre of FSU Jena, Germany) for their support in producing electron microscopic and light microscopic images.

Reprinted with permission by Laser 4/2016

Figure 8: TEM: Thermal treatment at 60 °C. Parts of the cytoplasm are damaged or dissolved as can be seen by the mitochondria (M) with inflated or wound-up christae (arrows). The nucleus (K) shows severely condensed areas (*).

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CASE REPORT

Minimally invasive inlay restoration from the hybrid ceramic VITA ENAMIC

Gerhard Werling1

Inlay restorations using CEREC procedures have been an established process in digital dentistry for decades. However, due to the required minimum wall thickness, a lot of tooth substance frequently had to be dissected in reconstructions of traditional ceramics.

Due to reduced minimum wall thicknesses, VITA ENAMIC (VITA Zahnfabrik, Bad Säckingen, Germany) allows minimally invasive restorations and can be precisely ground in thinly tapering edge areas. In the report, Dr. Gerhard Werling (Bellheim, Germany) explains the clinical procedures for an inlay-restoration of hybrid ceramic in region 24-26.

1. Initial situation Figures 1 and 2 show the initial situation. On the basis of the patient's history and according to the patient's request (male, 38 years), he was not treated with alternative methods (infiltration technique, fluoridation, regular controls, etc.). Instead, a filling cavity was carefully dissected on the tooth in which the caries had already penetrated the approximal enamel in the X-ray image. Surprisingly, in the clinical image, the caries had penetrated deep into the dentine, so that after extensive excavation, a considerable defect in the substance was present.

1

Dr. Gerhard Werling, Dentist, Bellheim, Germany

VITA® and other VITA products mentioned are registered trademarks of VITA Zahnfabrik H. Rauter GmbH & Co. KG, Bad Säckingen, Germany.

Figure 1: Initial situation.

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Figure 2: X-ray status – do the recognizable caries have to be treated, or can they be processed with alternative methods?

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CASE REPORT

Figure 3: Care was taken with the careful dissection of a filling cavity, but in the course of the excavation there were clinically extensive undermining defects.

Figure 4: “Extension for prevention” – but as minimally invasive as possible.

2. Material selection

"extension for prevention" rule - but as minimally invasive as possible. The hybrid ceramic VITA ENAMIC is very advantageous in this case. The unique network structure in which ceramic and acrylate polymers interpenetrate provides for enormous resilience and offers more freedom than traditional restoration materials.

Since the patient wanted a permanent enamel-like and toothlike restoration, composite could not be used as a restoration material. It was decided to proceed according to the

3. CAD/CAM workflow

Figure 5: The digital impression was made with an intraoral scanner.

Figure 6: The chewing surfaces were reconstructed using the biogeneric software.

Three VITA ENAMIC inlays were fabricated using the CEREC System (Sirona Dental, Bensheim, Germany). The intraoral scan was done using the CEREC Omnicam. With the biogeneric software, the reconstruction was done analogously to the missing chewing surfaces. In the grinding preview, the inlays were placed in the material blanks. The geometry EM-10 (8 x 10 x 15 mm) was chosen according to the shade determination with VITA Easyshade V (VITA Zahnfabrik) in the color 1M2-HT. The hybrid ceramic can be processed very simply and quickly by machine as well as manually. Thanks to the high load-bearing capacity and

Figure 7: By overlaying the counterbite, the contact points can be checked.

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WERLING

Figure 8: In the grinding preview, the designs were placed optimally in the blank (the inlay for tooth 26 is shown).

Figure 9: For the adhesive bonding, absolute drainage is ensured with a rubber dam.

edge stability, constructions with comparatively small wall thicknesses and thin-running edges are also feasible. Edge chipping, which can occur in traditional ceramics, are rare with this material.

4. Processing and integration It is advantageous that there is no firing process, and a shade characterization is possible if desired. The available shade selection (0M1 - 4M2) in two translucent steps, plus the good light transmission of the material allow for esthetically pleasing results. The inlays have been polished to a high gloss with the VITA ENAMIC Polishing Set in the clinic. The hybrid ceramic can also be easily polished intraorally. With VITA polishing instruments, the restoration edges can be polished in a unique, fine manner so that virtually no transition between the tooth and the restoration remains visible. Bonding is performed adhesively.

In dentistry, VITA remains the pioneer in tooth shade determination. Worldwide, four out of five shade values are

Figure 10: Result: A defect-oriented restoration with composite fillings was planned. The result was a minimally invasive restoration with VITA ENAMIC inlays.

determined with the VITA shade standard. VITA tools for analog and digital shade determination, communication and checking (e.g. VITA Easyshade V) ensure perfect shade matching.

Laboratories and dental practices in over 125 countries receive additional practical support and advice for their daily work through VITA's international course program.

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CLINICAL

Minimally invasive veneer restoration with ceramic-based restorative material

Mauricio Watanabe1

Aesthetics is an aspect that now plays an important role in modern dentistry. As ever more patients desire a ‘perfect smile’, dentists are increasingly called upon to produce highly aesthetic restorations and optimise the natural situation.

Reshaping of the teeth is a safe procedure with a predictable result, which can be routinely performed to create a more appealing and harmonic smile. However, it requires corresponding diagnostics and treatment planning, which takes both aesthetic and functional aspects into consideration.

The employment of minimally invasive techniques to preserve the tooth substance and neighbouring structures and the use of dental materials boasting the highest possible stability and biocompatibility are also essential. Restorations made from indirect composite veneers are one possible treatment.

Clinical case

1

Prof Dr Mauricio Watanabe Private Practice, São Paulo, Brazil Contact: mauriciowatanabe@yahoo.com. br.

A 20-year-old patient wanted to improve the aesthetics of his smile (Figure 1). Clinical examination revealed a diastema between the maxillary central incisors (Figure 2). The patient wanted a quick solution without the necessity for orthodontic treatment.

By analysing the photographs of the patient’s face, we were able to establish that the line running along the incisal edges and cusp tips of the canines in the maxillary anterior teeth did not form a regular curve. To get an attractive smile, it was thus necessary to adapt the shape of all four maxillary incisors in such a way that they formed a positive smile line (Figure 3).

During the lateral movements, there was no contact between the mandibular anterior teeth and maxillary incisors, opening up the possibility of lengthening them.

As the patient was young, a minimally invasive technique was required, which is why we decided on a procedure in which preparation of the teeth is not essential.

We chose an indirect technique in which the restorations were made from Admira Fusion (Voco), a material containing a ceramic matrix instead of the conventional methacrylate-based monomers, making it highly biocompatible.

The use of indirect veneers produced by the dentist represents an alternative to prefabricated veneers. Producing the veneers yourself also offers further advantages

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CLINICAL

Figure 1: A 20-year-old patient presented for dental treatment for aesthetic reasons due to a diastema between his maxillary central incisors.

Figure 2: The intraoral view shows the positions of the anterior teeth and their morphology in more detail.

Figure 3: We established that the four maxillary incisors would need to be treated if we were to achieve a satisfactory result.

Figure 4: As a treatment method, we selected the production of indirect restorations on a silicone model. This has advantages over the use of prefabricated facets, as producing them in-house allows for customisation and achievement of a better marginal seal.

such as the low relative cost, the possibility of personalising the tooth shape, the reduced thickness of the cement layer and the improved marginal seal.

The use of a mock-up, the basis for which was produced in this case with Die Silicone (Voco) (Figure 4), is advantageous for the simple and quick fabrication of indirect restorations. The corresponding shade for the restorative was selected right in the first treatment session.

This was done by applying a small quantity of each of the possible shades to the vestibular surface of one of the teeth to be restored and curing it. After comparing the shades, we decided on A1 (Figure 5).

therefore to lengthen the maxillary incisors.

Light-curing was followed by finishing and polishing with rubber polishers (Figure 7). We then photographed the model and superimposed the image with a photo of the patient smiling in order to check whether the size and alignment of the teeth had been successful (Figures 8 and 9).

The veneers were adapted directly to the patient’s teeth (Figures 10-13). A considerable advantage of this technique is the possibility of checking whether the result will satisfy the expectations before the treatment is completed. Trying in the restorations also allows the patient to see the result and request any changes to be made.

Once the marginal seal had been checked and the patient was happy with the aesthetics achieved, preparations were made for placing the indirect veneers. We chose the adhesive Futurabond U (Voco) in combination with the flowable composite Grandioso Flow (Voco) in shade A1 for the luting.

Restoration The restorative material was applied to the silicone model with a metal spatula for production of the actual mock-up and thus also for the veneers (Figure 6). During this step, it is important to try to stick to the planning specifications compiled based on the photo analysis. The aim was

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WATA N A B E

Figure 5: We selected the shade to be used in the first treatment session by applying a small quantity of the material to the tooth, smoothing off the surface with a large metal spatula and then curing the material. In this case, we decided on A1.

Figure 6: The restorative material (Admira Fusion, Voco) was applied directly to the finished silicone model. Spatulas were used to model the teeth in accordance with the morphology of the corresponding group of teeth. In this case, veneers were to be used to restore a proper curve to the line connecting the cusp tips of the canines and the incisal edges.

Figure 8: Superimposing a photo of the finished veneers with a photo of the patient allows us to predict the position and size of the restorations in the finished treatment.

Figure 7: Following polymerisation, we removed the veneers from the model, finished them and polished them with rubber grinders/polishers for ceramic restorations.

Figure 9: The simulation can be better assessed in black and white images, as can be seen here.

10

12

11

13

Figures 10-13: Try-in of the veneer on tooth UL1. Note the direction of insertion. It is important to observe the direction of insertion precisely when determining the order for inserting the restorations, as no preparation was performed.

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WATA N A B E

Figure 14: We used 000 retraction cord to retract the gingival margin for all the maxillary incisors.

Figure 15: 37% orthophosphoric acid is applied to each tooth and allowed to act for 15 seconds. The neighbouring tooth is protected with a separating strip made of polyester.

Figure 16: Teeth UR1 and UL1 following etching with phosphoric acid and drying.

Figure 17: The veneer for tooth UL1. It has been sandblasted with aluminium oxide to clean the interior surface.

Figure 18: Following application of the adhesive and drying with an air stream, the flowable composite Grandioso Flow (Voco) in shade A1 was used.

Figure 19: View following placement of the restoration. We also removed all material excesses with a number five probe prior to polymerisation.

The gingival margin was retracted with a number 000 retraction cord (Figure 14) and 37% orthophosphoric acid applied to the teeth for 15 seconds (Figure 15).

Following rinsing with water and drying of the etched vestibular surfaces (Figure 16), the adhesive was applied, the solvent dried with an air stream and light-curing was performed for 10 seconds.

The interior surfaces of the veneers were sandblasted with aluminium oxide (90Âľm) at a pressure of 60psi in order to

clean and roughen the surface. The homogeneous, clean surface of the interior of the veneer is evident when viewed against the light (Figure 17).

In the next step, the adhesive was applied to the same surface and then dried with a light air stream. We then distributed a small quantity of flowable composite on the surface (Figure 18) and placed the veneer on the corresponding tooth (Figure 19).

Following application, the excess composite was removed and then light polymerisation performed.

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WATA N A B E

20

21

22

23

Figures 20-23: Various views of the veneer restorations following completion.

25

24

26 Figure 24: Contact between the anterior teeth during the protrusive movement.

Once all veneers were in position, the restoration margins were finished with a number 15C scalpel and polished with rubber polishers. We assessed the results immediately upon completion (Figures 20-23). Corresponding grinding was carried out to ensure even contact between the mandibular incisors and maxillary central incisors during the protrusive movement (Figure 24).

Figures 25 and 26: Following grinding of the veneers, there was no further contact between the anterior teeth during the lateral movements.

Grinding was also employed to eliminate all contact between the veneers and the mandibular teeth during lateral movements (Figures 25 and 26).

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WATA N A B E

27

28

Figures 27 and 28: Images of the veneers under indirect light. The details are clearly visible.

29

30

Figures 29 and 30: View of the anterior teeth with a harmonic curve from vestibular and palatal perspectives.

31

32

Figures 31 and 32: A clear improvement in the tooth aesthetics can be seen when the preoperative and postoperative views are compared.

Views from vestibular and palatal under indirect light revealed that the details were well elaborated and that the indirect restorations blend harmoniously into the neighbouring structures (Figures 27-30).

A comparison of the preoperative and postoperative views shows a clear improvement of the tooth aesthetics (Figures

33

31 and 32) – and the positive effect this has had on the patient’s smile (Figures 33-35).

Reprinted with permission by Aesthetic Dentistry Today April 2017

34

35

Figures 33-35: A comparison: the patient’s smile before and after.

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CASE REPORT

Evaluating the fit of removable dentures with magnification systems Gualtiero Mandelli1 and Carlo Borromeo2

Nowadays, implant-supported prostheses are used more and more in people’s daily routines and removable prostheses in case of large rehabilitation offer aesthetic and functional advantages especially when support of the soft tissues is necessary. In this article, much attention will be given to the analysis and the design of the prosthesis in order to achieve predictable and repeatable results. During the construction of the structure and superstructure the microscope will be critical to achieve the maximum precision.

Introduction Removable prostheses are increasingly being used in everyday practice; in many cases you can achieve excellent functional aesthetic results even in the presence of a reduced number of implants, mostly when the patient wishes a stable total rehabilita-tion without the insertion of many implants. After the construction of a total temporary prosthesis in the lower jaw and the evaluation of all the problems and expectations of the patient, it is planned to produce a full denture anchored to a bar screwed on four implants (Fig. 1).

Step by step procedure In the first phase, after the implant surgery guided by a replica of the temporary restoration, the definitive impression was taken with a set-up created to restore aesthetics and function (Fig. 2). During the try-in, the template that was prepared in the laboratory

1

Dr Gualtiero Mandelli Visiting Professor at Specialisation School in Orthodontics, University of Brescia, Italy.

Private practice, Lombardia, Italy.

2

Carlo Borromeo, DT Dental Laboratory Borromeo, Italy.

Fig. 1: Lower removable prosthesis anchored with a CAD/CAM milled cobalt chromium bar with 2 degree of inclination with micro screwed attachments, with a cast cobalt chromium superstructure and incorporated in the resin.

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

Fig. 2: After preparing the master model mounted in the articulator, the teeth set-up is executed looking for the aesthetics and the function without worrying about the position and the type of the implants.

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CASE REPORT

4 Fig. 3: Over the master model a resin jig is produced after positioning the four metal transfers, and once cured it has been cut to eliminate any shrinkage or inaccuracy during the polym

5

Figs. 4 & 5: After the jig has been re-joined in the oral cavity, the wax-up was screwed in the transfers and a probe model was built for the verifying the accuracy and the passivity of the structure to be achieved.

over the master model was also checked (Fig. 3) in order to verify that there was agreement between the implants and the wax-up. The template was screwed on the implants, and blocked with the resin where it was separated; doing this we can be sure of the implants’ position. The template was returned to the laboratory to check the accuracy of the waxup’s position and their passivity against the master model (Figs. 4 & 5). At this point, after checking the set-up and the correct positioning of the wax-up, the model, the scan abutment, and the teeth set-up (Fig. 6) were scanned.

With the teeth set-up in light transparency, the design of the bar began, taking into consideration the available spaces, and keeping in mind the kind of prosthesis to create (Fig. 7). The design of the bar has to be accurate in all its details, including the surfaces facing the gums that should

enable the patient to clean their teeth daily. Only at this stage is it possible to identify what kind of attachments to use and where to put them in order to allow a good retention and a proper function (Fig. 8).

Once the design was finished, the file was sent to the milling centre, where it was milled in chrome-cobalt and returned to the laboratory where the first verification of its passivity and precision with the measuring gauge was performed (Fig. 9). After obtaining the evidence of its passivity on the master model, another test was done mainly on the area around the implants (Fig. 10). Sitting the lingual silicone key on the model the available space for the construction of the superstructure and the prosthesis was also checked; at this stage it is still possible to intervene modifying the project.

Fig. 6: With the resin jig the correspondence between the position of the wax-up and the implants located in the oral cavity is searched; after that the teeth set-up, the model and the implants position were scanned.

Fig. 7: After making the teeth set-up translucent, the design of the structure was begun, considering the available space and the position of the teeth and of the implants. It is also evaluated the masticatory plane in relation to the main plane of the structure.

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MANDELLI / BORROMEO

Fig. 8: The project of the bar continues, verifying all the details before sending the file, even the choice of the kind of anchor should be carefully evaluated according to the type of structure and the available spaces.

Fig. 9: After sending the file, the structure was produced by the milling centre, and the first check to be carried out is the precision and passivity test, which was performed on the verification model built with the help of resin jig.

The structures were sent to the dentist for tests in the oral cavity (Fig. 11). During the design, the correct areas where to locate the attachments were carefully evaluated and the milling centre was asked to produce the threads inside the bar in order to screw the attachments directly into it after

polishing and finishing; the most suitable attachments were then screwed to reach the retentiveness that was planned beforehand (Fig. 12). Once polished, the bar superstructure can be produced (Fig. 13). A crucial step is to refine and perfectly polish the areas around the implants and the soft

Fig. 10: Detail of the structure positioned with the silicone gums, checking the areas around the implants and adjacent to the bar to locate the correct positioning.

Fig. 11: After the bar was complete, the silicone of the set-up is positioned and the available spaces are checked.

Fig. 12: The possibility of screwing and unscrewing the retentive attachments gives not only the advantage to change them in case of wearing over time but also to change them at any time during the design of the superstructure.

Fig. 13: After carrying out all the necessary checks, the structure is finely polished before building the superstructure.

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Fig. 14: After polishing, the hygiene maintenance is checked towards the whole bar extension.

Fig. 16: The sprued superstructure with main and accessory pins and the stabilising bar.

tissues, because the superstructure did not have to compress any area (Fig. 14). The superstructure may be

Fig. 17: Cast superstructure.

Fig. 15: Once polished, the structure was built directly onto the superstructure with pattern resin and preformed castable pieces, and everything is controlled with the palatal silicone key.

made with an indirect technique duplicating the model, or with CAD, or directly on the structure with resin, as presented in this case report. Once done and before the casting, a further control with the silicone keys of the volumes and spaces available (Fig. 15) was made. After the checks, the superstructure was sprued with injection pins and with a stabiliser bar in the rear area (Fig. 16).

Immediately after the cast, the superstructure was controlled in all its parts to verify the quality of the alloy, and checked it fit over the bar with a marker spray and with minimal pressure (Figs. 17 & 18). With magnifier systems, every area of friction or incorrect pressure, both on the bar and in the superstructure, was searched; this allows the maximal function of the structure and of the retentive systems to be

Fig. 18: The superstructure is checked with a marking spray to verify the friction and the wrong points of contact for a proper sitting on the bar.

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MANDELLI / BORROMEO

Fig. 19: Detail of a pre-contact area during the insertion of the superstructure on the bar, the bar at this stage still had no retentive caps.

checked (Figs. 19 & 20). These magnifying devices, such as microscopes, allow for a better identification of the areas to be eliminated, and to distinguish those only to be polished, as metal abrasions must be eliminated (Fig. 21).

As soon as all these points are correctly managed, the result will be a good fitting of the superstructure with a smooth

Fig. 21: At a higher magnification, the areas of abrasion to be polished with adequate burs are searched to obtain proper friction.

24

Fig. 20: View with microscope of the friction points of the superstructure; during the test you can see the green areas and the abrasions.

friction, with the location of the attachments perfectly in the centre of the housings (Fig. 22). Only at this point were the black lab caps inserted, and the superstructure was inserted on the bar after being sprayed with marking spray; this allows you to check how the attachments act during the insertion (Fig. 23). Once the superstructure was extracted,

Fig. 22: The proper sitting of the superstructure was performed excluding the attachments in order to avoid any interference so that the correct interface can be searched.

Fig. 23: After checking the good friction of the superstructure all the retentive laboratory caps were placed, the bar and attachments sprayed anew with the marking spray and the correct sitting is checked.

26

25

Figs. 24 & 25: After removing the superstructure, the retentive areas of the attachments are searched with the microscope; the wrong areas of contact on the attachments show how they do not work properly. This because there are some points on the structure that have to be discarded as they will interfere with the bar insertion.

Fig. 26: After correcting of those points that interfere with the proper function of the attachments, the superstructure sits correctly over the bar and this is showed by the correct contact areas on the attachments.

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Fig. 27: After all these functional tests between the structure and superstructure, the available spaces are checked with the lingual silicone key.

Fig. 28: Using the vestibular silicone key, the teeth were repositioned.

Fig. 29: Having built the structure and the superstructure with the silicone keys, the teeth repositioning is easily done, having all the necessary space and without affecting the teeth

Fig. 30: Detail of the modeling of the soft tissues after the replacement of the teeth.

the attachments were checked using the microscope and it was detected that some areas were wrongly involved; indeed when the lacquer was removed (Figs. 24 & 25) around the attachments, incorrect contacts could be seen.

As a consequence, the caps will not work in the retentive

Fig. 31: The model with the prosthesis was inserted in the flask furnace for the processing.

areas of the spheres, this is because some points of the bar will hinder the superstructure’s insertion. Once those points of friction were removed at a second test, the structure sat better over the attachments (Fig. 26).

At this stage, the prosthesis could be finalised using the silicone to control the spaces and to relocate the teeth (Figs. 27 & 28). The importance of using the silicone keys throughout the design and final is visible in Figure 29, where the available space for the repositioning of the teeth is clearly visible. Without damaging the individual teeth, the set-up is reproduced in a practical and quick way, keeping all the features of the initial project (Fig. 30).

Fig. 32: The superstructure is being sandblasted and daubed with the prime and an opaque layer.

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34

33

Figs. 33 & 34: Details of the prosthesis after the resin injection.

Fig. 35: The internal part of the superstructure has been polished and all the retentive caps are inserted, during the try-in test it will be decided whether they have to be replaced with more or less retentive caps.

After repositioning and the new waxing was completed, the model with the denture was inserted in the injection flask, and attached with a silicone base (Fig. 31). When the wax was removed and the model cleaned and isolated; the teeth were repositioned in the silicone key, the superstructure sandblasted, treated with primer, opaque and cured and put back on the model (Fig. 32). The flask was injected with resin and after its curing, the prosthesis is finished, rechecked in the articulator and polished (Figs.

33 & 34). Even the inner side was refined and polished,

Fig. 36: Prosthesis and structures have been polished and ready for the final test.

and only after this final steps, the retentive caps were inserted inside the prosthesis. These caps have the retention that the patient desires and the project necessitates (Fig. 35). After the structure was polished, it was delivered to the clinician; polishing is a crucial part of the process to avoid plaque adherence (Fig. 36).

During the final test after the bar is screwed in the mouth, it is good to double check the surrounding areas of the implants and the correct spaces for daily hygiene (Fig. 37).

After its insertion, the prosthesis is re-checked and eventually

Fig. 37: The structure screwed into the oral cavity.

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40

39 Fig. 38: Final exam with prosthesis inserted; at this stage the prosthesis stability is tested.

Figs. 39 & 40: Patient with the inserted prostheses.

Conclusion

sitting of the superstructure on the bar and the proper function of the retentive systems; this eliminates the negative internal tensions of the whole system that can be transmitted to the implants, thus extending the life of attachments and of the whole system.

As pointed out in this article, the importance of using magnification systems is evident, including removable prosthesis, as they provide the possibility to check the good

Reprinted with permission by CAD/CAM 01/2017

discarded or remodeled; after a few days the patient was reviewed with great satisfaction of the work done and had a smile on his face (Figs. 38–40).

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Garrison’s new FitStrip™ Interproximal Finishing and Contouring System provides clinicians with diamond abrasive strips necessary to successfully restore a very wide variety of cases.

This comprehensive kit includes eight varieties of diamond coated abrasive strips, two interproximal saws and two interchangeable handles.

FitStrip™ is indicated for use in IPR, contact reduction, interproximal finishing and contouring, crown and bridge cement removal/clean up as well as separating inadvertently bonded teeth.

HU-FRIEDY

MORITA

EVEREDGE 2.0 SCALERS

TRI AUTO ZX2

EverEdge 2.0 uses a new, optimized heat control process in order to maintain the hard, sharp edge. This heat control, plus several manufacturing intricacies in Hu-Friedy’s proprietary process, provide the durability needed for effective procedures and continued use.

EverEdge scalers are sharp…EverEdge 2.0 scalers are even sharper.

Using an enhanced finishing process, Hu-Friedy’s professional artisans are creating edges that are scientifically measured to be over 60% sharper than the next closest competitor. Less force means easier, more comfortable scaling for the clinician and patient.

Introducing the new Tri Auto ZX2, engineered with innovative and dynamic design form. As the successor to the original Tri Auto ZX cordless endodontic motor with integrated apex locator, Morita continues to offer the only endodontic system in the market combining both functions in one handpiece. With easy, intuitive operation and automatic functions, Tri Auto ZX2 delivers predictable and safe endodontic instrumentation.

Highlighting Morita’s new OTR (Optimum Torque Reverse) and OGP (Optimum Glide Path) modes, Tri Auto ZX2 delivers, unique, compelling and reliable clinical application. Tri Auto ZX2: The complete endodontic preparation solution.

All products available from: HENRY SCHEIN HALAS • Tel: 1300 65 88 22 • www.henryschein.com.au 64 INTERNATIONAL DENTISTRY – AUSTRALASIAN EDITION VOL. 12, NO. 2

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