Case report with Dr. José Ignacio Zorzin

Rationalizing clinical workflows: This is the main reason for the use of universal products in adhesive dentistry. They are suitable for a wide range of indications and different application techniques, fulfil their tasks with fewer components than conventional systems and often involve fewer steps in the clinical procedure. Universal adhesives are a prominent example.

How do universal adhesives contribute to a streamlining of workflows?

When restoring teeth with resin composite, the restorative material will undergo volumetric shrinkage upon curing. By bonding the restorative to the tooth structure with an adhesive, the negative consequences of this shrinkage – marginal gap formation, marginal leakage and staining, hypersensitivity issues and the development of secondary caries – are prevented. The first bonding systems available on the dental market were etch-and-rinse adhesives, which typically consisted of three components: an acid etchant, a primer and a separate adhesive. Later generations combined the primer and the adhesive in one bottle, or were two or one-bottle self-etch adhesives. Universal adhesives (also referred to as multi-mode adhesives) may be used with or without a separate phosphoric acid etchant.

Fig. 1. Volumetric shrinkage of resin composite restoratives and its clinical consequences.

Which technique to choose depends on the indication and the clinical situation. In most cases, the best outcomes are obtained after selective etching of the enamel¹. Bonding to enamel is generally found more effective when the enamel is etched with phosphoric acid, while the application of phosphoric acid on large areas of dentin involves the risk of etching deeper than the adhesive is able to hybridize. When the cavity is small, however, selective application of the phosphoric acid etchant to the enamel surface may not be possible, so that a total-etch approach is most appropriate. Finally, in the context of repair, the self-etch approach may be the first choice, as phosphoric acid might impair the bond strength of certain restorative materials by blocking the binding sites. By using a universal adhesive, all these cases may be treated appropriately, as the best suitable etching technique can be selected in every situation.

Apart from the differences related to the use or non-use of phosphoric acid etchant on the enamel or enamel-and-dentin bonding surface, the clinical procedure is always similar with the same universal adhesive. The following clinical case is used to illustrate how to proceed with CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.) in the selective enamel etch mode, and it includes some details about the underlying mechanism of adhesion.

How to proceed with selective enamel etching?

A clinical example.

This patient presented with a fractured maxillary lateral incisor, luckily bringing the fragment with him. Hence, it was decided to adhesively lute the fragment to the tooth with an aesthetic flowable resin composite.

Fig. 2. Patient with a fractured maxillary lateral incisor.

Fig. 3. Close-up of the fractured tooth.

Fig. 4. Working field isolated with rubber dam.

As proper isolation of the working field makes the dental practitioner’s life easier, a rubber dam was placed using the split-dam technique. It works well in the anterior region of the maxilla, as the risk of contamination with saliva from the palate is minimal. Once the rubber dam was placed, the bonding surfaces needed to be slightly roughened to refresh the dentin. As the surfaces were also slightly contaminated with blood and it is important to have a completely clean surface for bonding, KATANA™ Cleaner was subsequently applied to the tooth structure, rubbed into the surfaces for ten seconds and then rinsed off. The cleaning agent contains MDP salt with surface-active characteristics that remove all the organic substances from the substrate. The fragment was fixed on a ball-shaped plugger with (polymerised) composite and also cleaned with KATANA™ Cleaner.

Fig. 5. Cleaning of the tooth …

Fig. 6. … and the fragment with KATANA™ Cleaner.

What followed was selective etching of the enamel on the tooth and the fragment for 15 seconds. Whenever selective enamel etching is the aim, it is essential to select an etchant with a stable (non runny) consistency – a property that is offered by K-ETCHANT Syringe (Kuraray Noritake Dental Inc.). Both surfaces were thoroughly rinsed and lightly dried before applying CLEARFIL™ Universal Bond Quick with a rubbing motion. This adhesive is really quick: Study results show that the bond established immediately after application is as strong and durable as after extensive rubbing into the tooth structure for 20 seconds.^2,3 The adhesive layer was carefully air-dried to a very thin layer and finally polymerized on the tooth and on the fragment.

Fig. 7. Selective etching of the enamel of the tooth …

Fig. 8. … and the fragment with phosphoric acid etchant.

Fig. 9. Application …

Fig. 10. … of the universal bonding agent.

Fig. 11. Polymerization of the ultra-thin adhesive layer on the tooth …

Fig. 12. … and the fragment.

What happens to dentin in the selective enamel etch (or self-etch) mode?

After surface preparation or roughening, there is a smear layer on the dentin surface that occludes the dentinal tubules, forms smear plugs that protect the pulp and prevents liquor from affecting the bond. When self-etching the dentin with a universal adhesive, this smear layer is infiltrated and partially dissolved by the mild self-etch formulation (pH > 2) of the universal adhesive. At the same time, the adhesive infiltrates and demineralizes the peritubular dentin. The acid attacks the hydroxyapatite at the collagen fibrils, dissolves calcium and phosphate and hence enlarges the surface. Then, the 10-MDP contained in the formulation reacts with the positively loaded calcium (and phosphate) ions. This ionic interaction is responsible for linking the dentin with the methacrylate and thus for the formation of the hybrid layer.^4,5

In the total-etch mode, the phosphoric acid is responsible for dissolving the smear layer and demineralising the hydroxyapatite. This leads to a collapsing of the collagen fibrils, which need to be rehydrated by the universal adhesive that is applied in the next step. Whenever the acid penetrates deeper into the structures than the adhesive, the collagen fibrils will remain collapsed. This will most likely result in clinical issues including post-operative sensitivity⁶.

When applying the adhesive system, a dental practitioner rarely thinks about what is happening at the interface⁷. However, every user of a universal adhesive should be aware of the fact that a lot is happening there. This is why it is so important to use a high-performance material with well-balanced properties and strictly adhere to the recommended protocols.

Fig. 13. Schematic representation of dentin after tooth preparation: The smear layer on top with its smear plugs occluding the dentinal tubules protects the pulp and prevents liquor from being released into the cavity.

Fig. 14. Schematic representation of dentin after the application of a universal adhesive containing 10-MDP: The mild self-etch formulation partially dissolves and infiltrates the smear layer, while at the same time demineralizing and infiltrating the peritubular dentin5.

In the present case, the tooth and the fragment now needed to be reconnected. For this purpose, CLEARFIL MAJESTY™ ES-Flow (A2 Low) was applied to the tooth structure. The fragment was then repositioned with a silicone index, held in the right position with a plier and light cured. To obtain a smooth margin and glossy surface, the restoration was merely polished. The patient presented after 1.5 years for a recall and the restoration was still in a perfect condition.

Fig. 15. Reconnecting the fragment with the tooth structure.

Fig. 16. Treatment outcome.

Why is it important to adhere to the product-specific protocols?

Universal adhesives contain lots of different technologies in a single bottle. While this fact indeed allows users to rationalize their clinical procedures, it also requires some special attention. As every highly developed material, universal adhesives need to be used according to the protocols recommended by the manufacturer. In general, materials may only be expected to work well on absolutely clean surfaces, while contamination with blood and saliva is likely to decrease the bond strength significantly. Depending on the type of universal adhesive, active application is similarly important, as is proper air-drying and polymerization of the adhesive layer. In addition, care must be taken to use the material in its original state, which means that it needs to be applied directly from the bottle to avoid premature solvent evaporation or chemical reactions. When adhering to these rules, universal adhesives offer several benefits from streamlined procedures to simplified order management and increased sustainability, as fewer bottles are needed and likely to expire before use.

Dentist:

DR. JOSÉ IGNACIO ZORZIN

Dr. José Ignacio Zorzin graduated as dentist at the Friedrich-Alexander University of Erlangen-Nürnberg, Germany, in 2009. He obtained his Doctorate (Dr. med. dent.) in 2011 and 2019 his Habilitation and venia legendi in conservative dentistry, periodontology and pediatric dentistry (“Materials and Techniques in Modern Restorative Dentistry”). Dr. Zorzin works since 2009 at the Dental Clinic 1 for Operative Dentistry and Periodontology, University Hospital Erlangen. He lectures at the Friedrich-Alexander University of Erlangen-Nürnberg in the field of operative dentistry where he leads clinical and pre-clinical courses. His main fields of research are self-adhesive resin luting composites, dentin adhesives, resin composites and ceramics, publishing in international peer-reviewed journals.

References

1. Van Meerbeek, B.; Yoshihara, K.; Van Landuyt, K.; Yoshida, Y.; Peumans, M. From Buonocore‘s Pioneering Acid-Etch Technique to Self-Adhering Restoratives. A Status Perspective of Rapidly Advancing Dental Adhesive Technology. J Adhes Dent 2020, 22, 7-34.
2. Kuno Y, Hosaka K, Nakajima M, Ikeda M, Klein Junior CA, Foxton RM, Tagami J. Incorporation of a hydrophilic amide monomer into a one-step self-etch adhesive to increase dentin bond strength: Effect of application time. Dent Mater J. 2019 Dec 1;38(6):892-899.
3. Nagura Y, Tsujimoto A, Fischer NG, Baruth AG, Barkmeier WW, Takamizawa T, Latta MA, Miyazaki M. Effect of Reduced Universal Adhesive Application Time on Enamel Bond Fatigue and Surface Morphology. Oper Dent. 2019 Jan/Feb;44(1):42-53.
4. Fehrenbach, J., C.P. Isolan, and E.A. Münchow, Is the presence of 10-MDP associated to higher bonding performance for self-etching adhesive systems? A meta-analysis of in vitro studies. Dental Materials, 2021. 37(10): 1463-1485.
5. Van Meerbeek, B., et al., State of the art of self-etch adhesives. Dental Materials, 2011. 27(1): 17-28.
6. Pashley, D.H., et al., State of the art etchand-rinse adhesives. Dent Mater, 2011. 27(1): 1-16.
7. Vermelho, P.M., et al., Adhesion of multimode adhesives to enamel and dentin after one year of water storage. Clinical Oral Investigations, 21(5): 1707-1715.

Clinical Case by DT Ghaith Alousi

What does it take to reconstruct teeth according to the patient’s individual sense of beauty? Experience shows that copying nature is the secret of success. To become a good duplicator, it is essential to develop an eye for detail with regard to tooth forms, surface morphology and the internal colour structure of the teeth to be copied. In addition, the duplicator needs to develop an understanding of the materials and tools used to copy those details. The last key success factor is taking pleasure in interacting with patients.

Read the clinical case created by Ghaith Alousi and published in the LabLine magazine’s Autumn edition now and learn about his approach to creating aesthetic restorations, mimicking nature and truly individualising restorative treatments.

By Dr. Clarence Tam, HBSC, DDS, AAACD, FIADFE

The use of both porcelain veneers to improve and restore the shape, shade and visual position of anterior teeth is a common technique in esthetic dentistry. The biomimetic aim in the restoration of teeth is not only the cosmetic domain, but also functional considerations. It is critical to note that the intact enamel shell of the palatal and facial walls with respect to anterior teeth are responsible for its innate flexural resistance. When dental structure has been violated by endodontic access, caries and/or trauma, every effort must be made to preserve the residual structure and strive to restore or exceed the baseline performance levels of a virgin tooth.

BACKGROUND

A 55 year old ASA II female with a medical history significant only for controlled hypertension presented to the practice for teeth whitening. It was foreseen that dental bleaching would not have an effect on the shade of a pre-existing porcelain veneer on tooth 1.2, and that this would need to be retreated following the procedure especially if the shade value changes were significant. The patient started with a baseline shade of VITA* 1M1:2M1; 50:50 ratio in the upper anterior region and 1M1 in the lower anterior region. Following a nightguard bleaching protocol with 10% carbamide peroxide worn overnight for 3-4 weeks, the patient succeeded in achieving a VITA* 0M3 shade in both upper and lower arches. As a result, there was a significant value discrepancy between the veneered tooth 1.2 and the adjacent teeth, and also increased chroma noted on the contralateral tooth 2.2 due to a facially-involved Class III composite restoration. This latter tooth also did not match the contralateral tooth in dimension and thus the decision was made to treat both lateral incisors with bonded lithium disilicate laminate veneers. The canine adjacent (2.3) featured localized mild to moderate cusp tip attrition, but the patient did not want to address this until following the currently-discussed veneers were placed. The goal of smile design at this stage is to ultimately establish bilateral harmony with the view to place an additional indirect restoration restoring the facial volume and cusp tip deficiency of tooth 2.3 in the near future.

PROCEDURE

A digital smile design protocol was not required for the initial intention, which was individual treatment of the lateral incisors, as slight variation is permitted in this tooth type, being a personality and gender marker of the smile. Prior to anesthesia, the target shade was selected using retracted photos featuring both polarized and unpolarized selections. The photographs were prepared for digital shade calibration by taking reference views with an 18% neutral gray white balance card (Fig. 1).

Fig. 1. Reference photograph taken with a 18% neutral gray card.

The basic body shade was VITA* 0M2 with an ingot shade of BL2. The patient was anesthetized using 1.5 carpules of a 2% Lignocaine solution with 1:100,000 epinephrine before affixing a rubber dam in a split dam orientation. The veneer on tooth 1.2 was sectioned and removed from tooth 1.2 and a minimally-invasive veneer preparation completed on tooth 2.2 (Fig. 2). Partial replacement of the old composite resin restoration was completed on the mesioincisobuccopalatal aspect of tooth 12 with the intact segment maintained. Adhesion to old composite was achieved using both micro particle abrasion and a silane coupling agent (CLEARFIL™ CERAMIC PRIMER PLUS, Kuraray Noritake Dental Inc.). Margins were refined and retraction cords soaked in an aluminum chloride solution and packed. Preparation stump shades were recorded. Final impressions were taken using both light and heavy body polyvinylsiloxane in a metal tray. The patient was provisionalized and sent away with instructions to verify the shade at the laboratory at the bisque bake stage. The models prepared by the laboratory verify the minimally-invasive nature of the case.

Fig. 2. Veneer preparation tooth 1.2, 2.2.

On receipt of the case, the patient was anesthetized and the provisionals removed. The preparations were debrided and prepared for bonding by abrading the surfaces using a 27 micron aluminum oxide powder at 30-40 psi. The veneers were assessed using a clear glycerin try-in paste (PANAVIA™ V5 Try-in Paste Clear, Kuraray Noritake Dental Inc.). Retraction cords were packed and the intaglio surface of the restorations treated using a 5% hydrofluoric acid for 20 seconds prior to application of a 10-MDP-containing silane coupling agent (CLEARFIL™ CERAMIC PRIMER PLUS, Kuraray Noritake Dental Inc.) (Fig. 3). The tooth surface was etched using 33% orthophosphoric acid for 20 seconds and rinsed. A 10-MDP-containing primer was applied to the tooth (PANAVIA™ V5 Tooth Primer, Kuraray Noritake Dental Inc.) (Fig. 4) and air dried as per manufacturer’s instructions. Veneer cement was loaded (PANAVIA™ Veneer LC Paste Clear, Kuraray Noritake Dental Inc.) (Fig. 5) and the veneer seated. The excess cement featured a non-slumpy character and maintained the veneer well in place during all margin verification exercises prior to a 1 second tack cure (Fig. 6).

Fig. 3. CLEARFIL™ CERAMIC PRIMER PLUS applied to intaglio surfaces of veneers.

Fig. 4. PANAVIA™ V5 Tooth Primer application to etched tooth surfaces.

Fig. 5. PANAVIA™ Veneer LC Paste Clear shade loaded onto prepared intaglio surfaces of veneers.

Fig. 6. PANAVIA™ Veneer LC Paste immediately after seating. Note the viscous, non-slumpy nature of the cement, which allows for ease of removal under both wet and gel-phase options.

The cement was rendered into a gel state, which facilitated “clump” or en masse removal of cement with minimal cleanup required (Fig. 7). The margins were coated using a clear glycerin gel prior to final curing to eliminate the oxygen inhibition layer (Fig. 8).

Fig. 7. Excess cement removal after tack curing for 1 second.

Fig. 8. Final curing of veneers from both palatal and facial aspects simultaneously.

The margins were finished and polished to high shine and the occlusion of the restorations verified as conformative. The post-operative views show excellent esthetic marginal integration (Fig. 9).

Fig. 9. Post-operative esthetic integration of veneers on 1.2 and 2.2.

On polarized photograph reassessment, the restorations are well-integrated into the new smile esthetically and functionally (Fig. 10), now awaiting esthetic augmentation of tooth 2.3 to match the contralateral canine.

FINAL SITUATION

Fig. 10. Final result with polarized photography on reassessment.

RATIONALE FOR MATERIAL SELECTION

Porcelain is often the chosen material for prosthetic dental veneers due to its innate stiffness in thin cross section, ability to modify and transmit light for optimal internal refraction and its bondability by way of adhesive protocols to composite resin. This trifecta allows for a maximal preservation of residual tooth structure whilst bolstering its physical function relative to flexural performance¹. The elastic modulus of a tooth can be restored to 96% of its control virgin value if the facial enamel is replaced with a bonded porcelain laminate veneer². The elastic modulus of lithium disilicate is 94 GPa whereas that of intact enamel is 84 GPa. The elastic modulus of dentin has been found to range from 10-25 GPa, whereas that of the hybrid layer can vary widely, indeed from 7.5 GPa to 13.5 GPa in a study by Pongprueska et al³. This low flexural resistance range reflects that of deep dentin and not that of superficial dentin, which does not reflect an ideal situation where a laminate veneer is bonded in as much enamel as possible, or in the worst case to superficial dentin. Maximal flexural strength of the hybrid layer is invaluable from a biomimetic standpoint. PANAVIA™ V5 Tooth Primer (Kuraray Noritake Dental Inc.) incorporates the use of the original 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) monomer, which elicits a pattern of stable calcium-phosphate nanolayering known as Superdentin, an acid-base resistant zone that is about 600x more insoluble than the monomer 4-MET, which is found in many other adhesives. Indeed, PANAVIA™ V5 Tooth Primer is used solely in conjunction with Kuraray Noritake Dental Inc. PANAVIA™ V5 cement and PANAVIA™ Veneer LC which both allow the primer to act as a bond without the need to cure the layer prior to cementation of the indirect restoration due to its dual cure potential when married together. If a bonding agent would be preferred, CLEARFIL™ Universal Bond Quick (Kuraray Noritake Dental Inc.), a multi-modal adhesive that also contains the essential amide monomer and 10-MDP components created by Kuraray Noritake Dental Inc., can be used. Of note, CLEARFIL™ Universal Bond Quick features exceptional flexural strength due to the accentuated cross-linking during polymerization afforded by the amide monomers, on the order of 120 MPa by itself⁴. PANAVIA™ Veneer LC is a cement system that features cutting edge technology that provides excellent esthetics and adhesive stability of your indirect restorations, whilst allowing a stress free workflow. It is a cement system that is a game changer; one that allows you to restore confidence in the patient, strength in the tooth-restoration interface, and bolsters your clinical confidence in the delivery of biomimetic excellence.

Dentist:

CLARENCE TAM

References

1. Magne P, Douglas WH. Rationalization of esthetic restorative dentistry based on biomimetics. J Esthet Dent. 1999;11(1):5-15. doi: 10.1111/j.1708-8240.1999.tb00371.x. PMID: 10337285.
2. Magne P, Douglas WH. Porcelain veneers: dentin bonding optimization and biomimetic recovery of the crown. Int J Prosthodont. 1999 Mar-Apr;12(2):111-21. PMID: 10371912.
3. Pongprueksa P, Kuphasuk W, Senawongse P. The elastic moduli across various types of resin/dentin interfaces. Dent Mater. 2008 Aug;24(8):1102-6. doi: 10.1016/j.dental.2007.12.008. Epub 2008 Mar 4. PMID: 18304626.
4. Source: Kuraray Noritake Dental Inc. Samples (beam shape; 25 x 2 x 2 mm): The solvents of each material were removed by blowing mild air prior to the test.

Clinical Case by MDT Mathias Berger

Highly reliable implants, advanced surgical techniques and innovative restorative materials, designs and approaches: modern implant dentistry has evolved into a predictable discipline producing aesthetic and functional outcomes, which are successful in the long term. Asking patients what they expect from a complex implant-supported reconstruction in the maxilla, natural aesthetics and biocompatibility are often demanded apart from functional aspects. With modern zirconia materials that offer the flexural strength required and well-balanced aesthetics, these demands are easily met.

The following case example is used to demonstrate how to maximise the potential of the recently introduced KATANA™ Zirconia HTML PLUS (Kuraray Noritake Dental Inc.), a multi-layered zirconia and the successor of KATANA™ Zirconia HTML with further improved strength and aesthetics. A special cutback design refined with hand instruments, shading with Esthetic Colorant for KATANA™ Zirconia and micro-layering with CERABIEN™ ZR porcelains (both Kuraray Noritake Dental Inc.) led to a quite natural result.

Start now reading the clinical case of MDT Mathias Berger by clicking image below!

LabLine magazine is an English language publication catering to the field of lab-side dentistry. It provides comprehensive coverage of the latest techniques and trends in dental laboratory technology and materials, showcasing them via sophisticated, challenging and aesthetic clinical cases done by some of the most known experts in Europe. With its expertly curated content, LabLine serves as an invaluable resource for dental professionals seeking to enhance their knowledge and stay at the forefront of the industry.

In the SPRING edition of LabLine you can find a wonderful AESTHETIC CASE by Mikel Villar Gonzales and DT Pilar Ballesteros Galan. The patient, a 21-year-old female had a hypoplasia defect on her permanent teeth, 1.1 and 1.2., presumably due to trauma on her deciduous anterior teeth. Click the image below and check out how the case was done!

Case by Michal Jaczewski

This patient came to the clinic to improve the aesthetics of her smile. After an aesthetic and functional analysis, it was decided to align and restore the teeth using a minimally invasive protocol with flowable composite.

INITIAL SITUATION

Fig. 1. The patient had worn teeth, visible abrasion, erosion and crowding in the lower arch.

Fig. 2. Situation after orthodontic treatment, full arch ready to restore.

Fig. 3. A silicon mould is used for the Flowable Injection Technique to restore the teeth with flowable composite. The silicone injection mould had injection channels prepared and was placed to check for proper fit.

Fig. 4. For this case it was decided to use CLEARFIL MAJESTY™ ES Flow Low in shade XW.

Fig. 5. Teflon tape was used, in order to separate the teeth.

Fig. 6. The restoration is completely additive; the teeth are not prepared at all. Total etching of the enamel is the best pre-treatment in this situation. K-Etchant Syringe (35% phosphoric acid) was applied for 10 seconds.

Fig. 7. A surgical suction tip was used in order to carefully remove the phosphoric acid gel and protect the isolations on the teeth. Followed by rinsing off completely with water in the usual manner.

Fig. 8. Each tooth was gently air dried for 10 seconds. CLEARFIL™ Universal Bond Quick was applied with a rubbing motion without additional waiting time. Followed by drying of the entire bonding treated surfaces by blowing mild air for more than 5 seconds until the bonding no longer moves.

Fig. 9. Light curing of each bonded tooth for 10 sec.

Fig. 10. The silicon mould is used to inject CLEARFIL MAJESTY™ ES Flow Low (optimal flowability, and properties for a case like this).

Fig. 11. Using the protocol „Treat one, skip one” several teeth are restored simultaneously.

Fig. 12. Situation directly after first round of injections.

Fig. 13. Situation after restoring all teeth, before polishing.

Fig. 14. To create a natural gloss the following polishing protocol was used: 1.) Sof-Lex™* discs, 2.) CLEARFIL™ Twist DIA for Composite polishing wheels, 3.) diamond paste and finally zinc oxide paste.

*Not a brand name of Kuraray Noritake Dental.

Fig. 15. High-shine results after polishing.

FINAL SITUATION

Fig. 16. Final restoration, immediately after treatment.

Fig. 17. Final restoration after 2 days.

Dentist:

MICHAL JACZEWSKI

Michał Jaczewski graduated from Wroclaw Medical University in 2006 and today runs his private practice in the city of Legnica, Poland. He specializes in minimally invasive dentistry and digital dentistry and is the founder of the Biofunctional School of Occlusion. Here he lectures and runs workshops with focus on full comprehensive patient treatments.

THE COMBINATION OF EFFECT LIQUIDS AND MICRO-LAYERING ON HIGHLY AESTHETIC ZIRCONIA IS THE EFFECTIVE WAY TO ACHIEVE OUTSTANDING RESULTS

Case by Leonidas Dimitriou, MDT

As an addition to its well-aligned portfolio of multi-layered zirconia (KATANA™ Zirconia Multi-Layered series) and veneering porcelain for zirconia (CERABIEN™ ZR), Kuraray Noritake Dental Inc. has recently introduced a set of dyeing liquids. Esthetic Colorant for KATANA™ Zirconia is applied to the surface of the monolithic or anatomically reduced zirconia restoration prior to the final sintering procedure. In this way, it is possible to imitate typical internal colour effects of natural teeth quite easily. Depending on the desired outcome, users may add just a final layer of glaze, liquid ceramics or stains and porcelains to their zirconia restorations treated with Esthetic Colorant. The following two case examples are used to demonstrate two different procedures involving the use of the effect liquids.

CASE EXAMPLE 1

In the first case, we produced three two-unit splinted crown restorations for six maxillary anterior teeth. The zirconia crowns (made of KATANA™ Zirconia YML) were anatomically reduced and individualized with Esthetic Colorant mainly in the incisal and cervical areas immediately after milling. For the application of the selected liquids, we used the Liquid Brush Pen specifically developed for Esthetic Colorant. The restorations were dried for half an hour, placed in the sintering furnace for sintering according to the recommended protocol for KATANA™ Zirconia and subsequently finished with CERABIEN™ ZR porcelains. Finally, CERABIEN™ ZR Paste Stain Glaze was applied for the final high-gloss finish.

Fig. 1. Pre-sintered anatomically reduced crowns after milling.

Fig. 2. Esthetic Colorant applied to the milled restorations.

Fig. 3. Appearance of the individualized restorations after the final sintering procedure.

Fig. 4. Restorations after porcelain layering.

FINAL SITUATION

Fig. 5. Final restorations with a natural appearance. The effects created with Esthetic Colorant shine from deep within the restorations.

Fig. 6. Lateral view of the final restorations from the left.

Fig. 7. Lateral view of the final restorations from the right.

CASE EXAMPLE 2

In this second case, two three-unit restorations were produced using KATANA™ Zirconia YML in the colour A3. We designed and milled them in full contour, then reduced them with hand instruments by 0.2 mm and added some texture effects to the surface before applying Esthetic Colorant. In this case, we played with different shades of Esthetic Colorant. Even when applied on a minimally reduced or monolithic surface, the liquids are able to create a nice depth effect as they diffuse into the zirconia structure. The amount of liquid applied is easily controlled with the Liquid Brush Pen, so that the intensity of the colours is predictable. After sintering, we added some internal stains, CERABIEN™ ZR Luster Porcelain and a final layer of CERABIEN™ ZR FC Paste Stain Glaze to finish the restorations. The outcome speaks for itself.

Fig. 8. Milled monolithic restorations with a pronounced surface texture.

Fig. 9. Vestibular and palatal surfaces individualized with Esthetic Colorant to create and intensify some natural colour effects.

Fig. 10. Appearance of the restorations immediately after sintering.

Fig. 11. Restorations after internal staining.

Fig. 12. A layer of luster porcelain applied to the minimally reduced restorations.

FINAL SITUATION

Fig. 13. Final outcome after glazing.

Dentist:

LEONIDAS DIMITRIOU, MDT

Case by CDT Daniele Rondoni and MDT Roberto Rossi

Working with high-translucency, multi layered zirconia (KATANA™ Zirconia Multi-Layered series from Kuraray Noritake Dental Inc.) paves the way toward indirect restorations that are closely adapted to our patients’ needs. Reduced wall thicknesses allow for minimally invasive tooth preparations, while polished zirconia in the occlusal contact areas provides for an antagonist-friendly behaviour. All this is possible due to the high aesthetic potential and homogeneous structure of the materials, which work well with a full-contour design or slight vestibular cutback. For individualization or characterization, different options are available. The portfolio of finishing solutions from Kuraray Noritake Dental has just been complemented by Esthetic Colorant for KATANA™ Zirconia, a set of twelve dyeing liquids for the company’s multilayered zirconia. They are applied to the milled restoration surface prior to sintering.

Some readers may wonder why there is a need for effect liquids applied to pre-shaded zirconia with a multi-layered colour structure. Being aware of natural teeth’s unique play of colours stemming from the shape and shade of the dentin core, however, the reason is quite obvious: Esthetic Colorant diffuses into the zirconia structure, hence allowing us to create depth effects even in monolithic restorations. Moreover, it enables the user to pre-treat tissue areas, and even by using the liquids on cutback designs, we are able to reproduce case-specific internal optical characteristics quite easily. Our standard approach for the use of Esthetic Colorant on KATANA™ Zirconia HTML Plus is described by means of the following case example: An implant- and tooth-based twelve-unit bridge with a slight vestibular cutback design, finished with Esthetic Colorant and CERABIEN™ ZR Porcelain.

Fig. 1. Restoration with sintering support removed from the blank.

Fig. 2. Esthetic Colorant for KATANA™ Zirconia: Available shades.

Fig. 3. Frontal view of the milled restoration after the application of Esthetic Colorant. A chromatic map is not needed since the colours of the applied liquids are clearly visible.

Fig. 4. Occlusal view of the milled restoration after the application of Esthetic Colorant. The liquids were applied with the Liquid Brush Pen for Esthetic Colorant.

Fig. 5. Frontal view: Appearance of the restoration after sintering.

Fig. 6. Occlusal view: Appearance of the restoration after sintering.

Fig. 7. Beautiful translucency and mamelon structures in the incisal area.

Fig. 8. Situation after the application of a thin layer of CERABIEN™ ZR Porcelain, which creates an enamellike window effect and reveals the play of colours found underneath.

Fig. 9. Restoration after firing and glazing.

FINAL SITUATION

Fig. 10. Beauty shots…

Fig. 11. … of the final restoration.

Easy handling and application, impressive colour effects: Esthetic Colorant perfectly fits into our micro-layering approach with a cutback design adjusted to the age and needs of every patient. Being applied on the pre-sintered zirconia surface, the liquids do not require any extra heat treatment – the restoration is simply dried and then sintered as usual. Esthetic Colorant may be used instead of or in combination with internal stains, luster porcelains and liquid ceramics – whatever complements a laboratory’s existing approach to highly aesthetic zirconia restorations.

Dentists:

Case by Kokla Thalia, Postgraduate student in Restorative Dentistry program, Faculty of Dentistry, National and Kapodistrian University of Athens, Greece

Restoring Class II cavities can be challenging due to limited access to the posterior area, where the interproximal contact needs to re-established in a proper way. Inadequate contacts tend to result in increased plaque accumulation, food impaction and, as a consequence, the development of caries and irritation of the interproximal gingiva. Therefore, it is essential that the interproximal contact is restored based on the model of nature. A suitable matrix system and a proper clinical protocol can help us succeed in this context. The following clinical case is used to illustrate a possible strategy.

Fig. 1. Initial clinical situation. 23-year-old female patient with caries on the mandibular left second premolar.

Fig. 2. Situation after cavity preparation, isolation of the working field with rubber dam and the placement of a sectional matrix fixed with a ring. It is essential that the matrix imitates the natural shape of the contact area, which is usually rather flat or concave cervically and convex in the middle and occlusal parts.

Fig. 3. Etching of the tooth structure with phosphoric acid etchant. Afterwards, the adhesive needs to be applied (in this case, Universal Bond Quick was used according to the manufacturer’s instructions).

Fig. 4. CLEARFIL MAJESTY™ ES-2 Premium in the shade A3E is applied in the distal box to build up the wall first. In this way, the available space is used to model the most critical part of the restoration before simply filling the cavity in increments with the dentin shade A3D.

FINAL SITUATION

Fig. 5. Final restoration after finishing and polishing. In accordance with the concept behind CLEARFIL MAJESTY™ ES-2 Premium with its pre-defined shade combinations, the final enamel layer was build-up using the shade A3E. However, the use of a single opacity is also possible in the posterior region depending on the aesthetic demands.

CONCLUSION

By elevating deep interproximal margins, it is possible to focus on the critical designing of the contact point when there is still sufficient space available to do so. This simplifies the procedure, while all that is left to do can be managed in a straightforward way like a Class I restoration.

HOW MANY SHADES DO WE NEED?

Case by Gasparatos Spyros, Postgraduate student in Restorative Dentistry program, Faculty of Dentistry, National and Kapodistrian University of Athens, Greece

Restoring anterior teeth with large defects using composite seems to be quite challenging. With high-performance materials at hand and a systematic layering concept in mind, however, it is possible to produce highly aesthetic results in a reproducible way. The clinical case below is used to illustrate a dual-shade layering technique with CLEARFIL MAJESTY™ ES-2 Premium, a composite system with pre-defined colour combinations.

CASE EXAMPLE

The patient, a young male, was unhappy with the appearance of his maxillary anterior teeth. Several years ago, his central incisors had been restored with composite. These existing restorations had defective and heavily discoloured margins, while their shade did not match the adjacent natural tooth structure. The maxillary lateral incisors were peg-shaped (microdontia). Economic considerations and the desire to save as much natural tooth structure as possible made the team decide to restore all four maxillary incisors with composite. CLEARFIL MAJESTY™ ES-2 Premium became the material of choice as it eliminates the need for complicated shade combination formulas and supports predictable outcomes.

Fig. 1. The patient’s initial smile.

Fig. 2. Intraoral image of the initial situation with defective composite restorations and microdonts. Two composite buttons on the right lateral incisor are used to verify the determined shade combination.

RESTORING THE CENTRAL INCISORS

We decided to restore the central incisors first and then focus on the lateral incisors. The tooth shade was determined using the VITA™ classical A1-D4 shade guide, while composite buttons were applied to the teeth to verify the determined shade combination. In order to simplify the restoration procedure, a palatal silicon index was produced before removing the existing restorations. During minimally invasive tooth preparation, bevels were created at the margins to provide for a smooth optical transition from the natural tooth structure to the composite.

An adhesive (CLEARFIL™ Universal Bond Quick) was applied after selective etching of the enamel to achieve a strong bond. With the aid of the silicon index, it was easy to create the palatal shells of the restorations with CLEARFIL MAJESTY™ ES-2 Premium in the shade A3E (enamel), which matches the determined tooth shade A3. The dentin core was built up with the same composite in the recommended shade A3D (dentin), mamelons were modelled and some CLEARFIL MAJESTY™ ES-2 Premium in the shade WD added for the incisal halo, while some individual effects (like enamel cracks) were imitated with brown stain. The build-up was finalized in the interproximal and labial areas with composite in the shade A3E. Between the central incisors, a wedge was used to retract the papilla and facilitate the designing of the interproximal contact area. The finished and pre-polished restorations already had a natural appearance.

Fig. 3. Central incisors after removal of the old restorations and the beveling of the enamel.

Fig. 4. Light-cured palatal shells made of CLEARFIL MAJESTY™ ES-2 Premium in the shade A3E.

Fig. 5. Build-up of the dentin core with mamelons individualized with the shade WD and brown stain.

Fig. 6. Situation after finalization of the central incisor restorations with composite in the enamel opacity.

Fig. 7. Central incisor restorations after finishing and initial polishing.

RESTORING THE LATERAL INCISORS

Tooth preparation was not required on the lateral incisors. Instead, they were merely cleaned after a slight roughening of the enamel surfaces. The build-up procedure was similar to the one used for the central incisors. The adjacent tooth was protected with PTFE tape, and the palatal shell was created with the aid of a finger instead of a silicone index. Afterwards, we focused on the build-up of the interproximal walls before a small amount of dentin was placed and the shape was finalized by applying the labial enamel layer.

Fig. 8. Build-up of the left lateral incisor.

Fig. 9. Situation after finishing and polishing.

FINAL SITUATION

Fig. 10. Final smile of the patient's demands.

CONCLUSION

Two different opacities, a single shade combination and some bleached shade plus stain for special effects – in the present patient case, a simple formula allowed us to create lifelike anterior restorations. With one enamel and one dentin paste used, it is possible to simply rebuild the natural anatomy without the risk of ending up with a bulky core that – once reduced – will lose its special optical structure. It is also easy to control the thickness of the final enamel layer with its huge impact on the light-optical properties of the whole restoration. For most patients and teeth with a simple or medium-to-complex internal colour structure, the selected concept is very well suited and will lead to pleasing outcomes.