Clinical case by Kostia Vyshamirski, DT

Digital technologies for computer-aided imaging, planning, design and manufacturing are valuable tools that support dental technicians in their daily work. Combined with traditional approaches, those digital tools allow us to assess, shape, and finally meet or even exceed patient expectations. The case below is a perfect example: We produced 20 natural bleach restorations made of KATANA™ Zirconia YML and CERABIEN™ ZR Porcelains and of Noritake Super Porcelain EX-3 (Kuraray Noritake Dental Inc.), respectively.

INITIAL SITUATION

The aim was to create a new white, still natural smile. It was decided to replace the old crowns in the maxilla and to create a wider and brighter smile by adding laminate veneers in the maxilla and mandible.

Fig. 1. Initial clinical situation.

DIGITAL SMILE DESIGN AND DIAGNOSTIC WAX-UP

Digital smile design and a diagnostic wax-up are great tools for analysing and planning a new smile. Intraoral scans and portrait photographs of the patient served as the basis for the development of the ideal proportions and shapes. Once the virtual designing of the new restorations was completed (software: exocad DentalCAD), the wax-up models were printed. By transferring the wax-up into the patient’s mouth via an index or matrix, it is possible to test and assess the outcome intraorally. In this step, aesthetic and functional analysis should be the priority.

Fig. 2. Digital smile design based on an image.

Fig. 3. Computer-aided waxing up in the maxilla based on the smile design.

Fig. 4. Completed virtual wax-up for the maxilla and mandible.

Fig. 5. Wax-up transferred into the patient’s mouth for functional and aesthetic analysis.

Fig. 6. The planned new bright smile.

ALVEOLAR PRINTED MODEL

Precise and functional models are essential for the production of accurate, aesthetic restorations in the laboratory. The model builder software SHERAeasy-model (SHERA) and a 3D printer (ASIGA MAX UV, Asiga) were used to produce solid models and alveolar models with full gingival information and removable dies.

Fig. 7. Alveolar models printed in gingiva and tooth colours.

Fig. 8. Printed models with articulator holding plates and removed dental elements.

REFRACTORY DIE DUPLICATION AND ARTICULATION

The refractory die technique allows for the production of extremely thin-walled restorations and hence supports minimal tooth structure removal. For this reason, the approach seems best suited for all previously untreated teeth without major defects. The printed dies were duplicated in the refractory die material before mounting the models in the articulator for a transfer of the maxillomandibular relations.

Fig. 9. Process of duplicating printed dies in the refractory material.

Fig. 10. Articulating the models.

PRODUCTION OF THE RESTORATIONS

To achieve the best results, it is essential to select the best material for each specific situation. For the production of the crown frameworks used to restore the six maxillary anterior teeth, KATANA™ Zirconia YML in the shade NW appeared to be the ideal option. Their intaglio surfaces were treated with Esthetic Colorant (Kuraray Noritake Dental Inc.) in the shade OPAQUE to prevent a shining through of the discolourations found on some of the prepared teeth. After sintering of the frameworks in a high-temperature sintering furnace (Nabertherm) at 1,550° C, CERABIEN™ ZR porcelains were applied as illustrated below. For the creation of natural effects inside the restorations – i.e. between the layers of porcelain –, we use the internal stain technique (ILS). This procedure is very predictable and fast. Each step during porcelain build-up and staining was recorded with photos to monitor the entire process and to capture all information on the individual protocol steps. The porcelain veneers (Super Porcelain EX-3, Kuraray Noritake Dental Inc.) were produced on the refractory dies to restore the premolars in the maxilla and central incisors to second premolars in the mandible.

Fig. 11. Refractory dies and zirconia frameworks on the model.

Fig. 12. Wax-up on the model with removable dies.

Fig. 13. KATANA™ Zirconia YML frameworks on the model.

Fig. 14. Opacity control with CERABIEN™ ZR Opacious Body OB White to optimise brightness.

Fig. 15. Application of CERABIEN™ ZR Body NW0.5 to restore the cores of the crowns using a silicon index.

Fig. 16. CERABIEN™ ZR porcelains E1 and LTX applied to create translucency at the incisal edge.

Fig. 17. Prepared surface ready for internal stain application.

Fig. 18. Creation of mamelons and incisal effects with CERABIEN™ ZR internal stains.

Fig. 19. Adaptation of the incisal third with a mamelon mixture of internal stain shades (white, mamelon orange and bright).

Fig. 20. Outcome of the internal staining procedure.

Fig. 21. CERABIEN™ ZR Luster application using the Interchangeable Build-up Technique, application of CCV1 in the cervical area.

Fig. 22. CERABIEN™ ZR porcelains ELT1 used for the core, LTX for the incisal area and ELT3 for the ridges.

Fig. 23. Restorations finished by carving, hand polishing and a self-glaze bake.

Fig. 24. Layering map summarizing the porcelain layering procedure.

FIT ASSESSMENT AND TRY-IN

When the production process was complete, the restorations were placed on the solid models (printed master casts). This step is very important to validate the passive fit and contact points of each crown and veneer. Afterwards, it was time to try-in and check all the restorations intra-orally.

Fig. 25. Final restorations ready for fit assessment.

Fig. 26. Maxillary restorations: Checking of the passive fit and contacts on the model.

Fig. 27. Mandibular restorations: Checking of the passive fit and contacts on the model.

Fig. 28. Intra-oral try-in of the crowns.

DEFINITIVE PLACEMENT AND FINAL OUTCOME

Refractory ceramic veneers were cemented via an adhesive protocol using a resin-based composite. Opaque glass ionomer cement was used to cement the zirconia crowns.

At the recall about one month after restoration placement, we saw amazing gum conditions and a happy, healthy and beautiful smile!

Fig. 29. Image taken right after definitive placement of the crowns.

Fig. 30. Nice pink-and-white aesthetics achieved with the all-ceramic restorations.

Fig. 31. Amazing gum conditions found one month after restoration placement.

Fig. 32. Happy, healthy and beautiful smile.

Fig. 33. The new smile exceeds expectations.

Case by Andreas Chatzimpatzakis

With CERABIEN™ ZR, Kuraray Noritake Dental Inc. offers a whole porcelain portfolio for the finishing of restorations based on zirconia. Originally developed for complex layering techniques, the synthetic feldspathic porcelain powders, liquid ceramics, internal and external stains allow for the creation of beautiful dental artwork. We love to work with the system as it offers consistent handling and mechanical properties, allowing us to produce predictable outcomes.

However, the complexity of the system with its huge number of different shades can pose challenges to less experienced users. This complexity is further increased when different substructure materials are used, as CERABIEN™ ZR works exclusively on zirconia, so that users would need to select and manage a second porcelain system when opting for a lithium disilicate framework, for example.

For dental technicians who would like to keep it smartly simple, the new CERABIEN™ MiLai line-up is certainly a great solution. Specifically developed for micro-layering on pre-shaded, highly translucent substructure materials such as lithium disilicate or a latest-generation zirconia, CERABIEN™ MiLai porcelains and internal stains may be applied in a thin (micro-) layer on restorations with a small (vestibular) cut-back. Just like CERABIEN™ ZR, the new system is based on synthetic feldspathic porcelain delivering consistent properties, but the line-up is reduced to 15 internal stains and 16 porcelains. As the CERABIEN™ MiLai has a firing temperature of 740 °C (1,364 °F), it works on oxide ceramics like zirconia, but also on reinforced silicate ceramics like lithium disilicate*.

*The material should have CTE value within 9.5~11.0×10^-6 /K (50~500 °C)

Consequently, the system may be used as the universal porcelain system for micro-layering on aesthetic ceramics. With its slim portfolio, it fits the philosophy of creating impressive restorations with fewer components, layers and bakes very well, as demonstrated in two different case examples below.

VENEERS BASED ON LITHIUM DISILICATE

Fig. 1. Six anterior veneers made of lithium disilicate (Amber Press LTA2 HASS Bio), designed with a slight cut-back to create the space needed for micro-layering.

Fig. 2. Restorations after the application of CERABIEN™ MiLai Value Liner 1 followed by wash firing and internal staining. This type of porcelain increases the value of lithium disilicate restorations. By staining the core, we control the chroma and add some internal characteristic effects. In this case, we added Cervical 2 to the marginal area and characterized the incisal third with Cervical 2 and Incisal Blue 1 & 2.

Fig. 3. First porcelain layer consisting of CERABIEN™ MiLai LT1 applied to the cervical, ELT1 to the mesial third and TX to the incisal third before …

Fig. 4. … and after the first bake.

Fig. 5. Application of internal stains for special effects like cracks, intense chroma etc.

Fig. 6. Second porcelain layer consisting of CERABIEN™ MiLai LT1 applied to the canines as well as the cervical third of the central and lateral incisors, while the middle and incisal third of the four incisors is individualised with LTx.

Fig. 7. Finished restorations on the master cast.

Fig. 8. Lateral view of the restorations highlighting their natural surface texture.

ANTERIOR BRIDGEWORK BASED ON ZIRCONIA

Fig. 1. KATANA™ Zirconia HTML Plus (A2 shade) structure immediately after milling.

Fig. 2. Appearance of the substructure after sintering.

Fig. 3. High translucency of the zirconia with the applied CERABIEN™ MiLai stains and porcelains on teeth and gingiva.

Fig. 4. Palatal view of the individualized restoration before the firing process.

Fig. 5. Restoration ready for try-in.

CONCLUSION

The two different cases confirm that CERABIEN™ MiLai works very well on lithium disilicate and zirconia. Despite the reduced number of stains and shades, it is possible to imitate most of the shades and individual effects found in natural teeth, which are important for lifelike outcomes. Hence, the new material is worth a try for everyone who prefers standardized and simplified procedures.

Cases by DT Ioulianos Moustakis and MDT Andreas Chatzimpatzakis

Producing dental restorations that are not recognizable as such – this is probably the ultimate goal of every dental technician. For a long time, pursuing this goal was complicated by core materials whose optical properties were very different from those of natural teeth. The dark metal or opaque zirconia substructures had to be masked by applying multiple layers of intensively coloured ceramic powders, topped by more translucent porcelains imitating the enamel.

The rise of modern, tooth-coloured core materials such as lithium disilicate and zirconia has changed the game. With a core that is highly aesthetic, translucent and close to the final shade, it became much easier to produce a restoration that is virtually indistinguishable from the adjacent teeth. The thickness of the porcelain layer decreased as did the number of shades to be combined and necessary bakes to be conducted. The use of the existing porcelain systems for the new micro-layering techniques posed several new challenges: those systems originally developed for opaque zirconia were indicated for the more translucent zirconia core materials, but usually not for lithium disilicate. Moreover, the complexity of the systems made their use unnecessarily complicated for inexperienced users.

Consequently, Kuraray Noritake Dental Inc. developed a new porcelain system for micro layering on zirconia and lithium disilicate core materials. The portfolio of CERABIEN™ MiLai, which refers to micro-layering and the Japanese word for future (mirai), consists of 15 internal stains (13 tooth colours including Bright to boost the translucent and Fluoro to boost the fluorescent effect, and two tissue colours) and 16 porcelains (12 tooth porcelains and four tissue porcelains). Hence, it enables dental technicians to implement a modernized version of the original Internal Live Stain Technique developed by Hitoshi Aoshima in the early 1990s in a porcelain layer of minimal thickness.

The following demo cases are used to show how to achieve lifelike aesthetic restorations based on aesthetic zirconia and on lithium disilicate. Illustrating each step, the cases allow users to anticipate how much time and effort can be saved compared to traditional layering techniques.

CASE 1

MAXIMALLY SIMPLE APPROACH ON LITHIUM DISILICATE

In this case, the idea was to restore the six maxillary anterior teeth in a simple way. The selected core material for the planned veneers was Amber Press (HASS Bio) LT in the shade B1. The lithium disilicate restorations were pressed with a micro cut-back and their fit was checked on the model, followed by surface texturing, sandblasting and steam cleaning [Fig. 1a]. When the veneers are milled instead of pressed, the procedure is the same. After that, the restorations are ready for the application of the CERABIEN™ MiLai internal stains for characterization of the core. In order to achieve the desired result, it is critical to mix the selected stains with the internal stain Bright responsible for a translucent effect. The chroma map for internal staining is shown in figure 1b, the outcome of the procedure in figure 1c. Subsequently, the veneers were built up to their final anatomy with selected CERABIEN™ MiLai Porcelains [Fig. 1d] to imitate the enamel and create a window effect. In this approach, simple layering and a single bake are sufficient to create the desired restoration. After glazing with Clear Glaze, finishing of the restorations was accomplished with paper-abrasive cones, a rubber polisher and polishing paste. The outcome is shown in figure 1e.

Fig. 1a. Pressed lithium disilicate veneers after surface optimization (grinding), sandblasting and steam cleaning on the model.

Fig. 1b. Chroma map for the application of CERABIEN™ MiLai Internal Stains to the lithium disilicate surface. We selected B+ (red colour) for the cervical area. For the proximal and middle incisal areas, Incisal Blue 1 & 2 (gradient blue colour) were applied and incisally in the middle, we chose Cervical 2 (orange colour). Tip: all internal stains were mixed with Bright and IS Liquid.

Fig. 1c. Appearance of the veneers after the application of CERABIEN™ MiLai Internal Stains.

Fig. 1d. CERABIEN™ MiLai Porcelains applied on top of the internal stains: LT1 is used for the cervical area (red) and a mixture of TX and E2 (30:70 ratio) for the middle and the incisal third.

Fig. 1e. The final restorations after glazing with Clear Glaze and mechanical polishing using paper-abrasive cones, a rubber polisher and Pearl Surface Z (Kuraray Noritake Dental Inc.).

Images courtesy of Andreas Chatzimpatzakis.

CASE 2

ADVANCED APPROACH ON LITHIUM DISILICATE

In order to imitate a more complex inner colour structure with mamelons, different levels of translucency and more individual effects, a slightly more complex micro-layering approach was selected. Again, the core was produced using Amber Press in the LT variant and the shade B1. After pressing and fitting on the model, we reduced the incisal third to create space for the transparent porcelain [Fig. 2a]. Subsequently, an extremely thin layer of CERABIEN™ MiLai Porcelain adding translucency to the enamel surface (TX) was applied in the incisal third of the veneers [Fig. 2b]. In this way, it is possible to create an optimally translucent basis for the application of the internal stains. The first bake was conducted and the surfaces were sandblasted as well as steam cleaned to create the conditions needed for internal staining [Figs. 2c and 2d]. The chroma map for and outcome of the internal stain application are shown in figures 2e and 2f. Afterwards, a final layer of CERABIEN™ MiLai Porcelain was applied [Fig. 2g]. All four incisors received a layer of LTx to add ultimate translucency and opalescence to the enamel, while LT1 was the material of choice in the cervical third of the canines, where LTx completed the layer in the other areas. As LT1 is slightly less translucent and opalescent, a natural effect is obtained in this way. The outcome obtained after glazing and mechanical polishing is shown in Figure 2h.

Fig. 2a. Lithium disilicate veneers reduced for the advanced layering procedure involving more porcelains and bakes.

Fig. 2b. Thin layer of TX applied to the incisal third of the restorations to boost the translucency in this area.

Fig. 2c. Appearance of the veneers after the first bake.

Fig. 2d. Ceramic surfaces after sandblasting and steam cleaning.

Fig. 2e. Chroma map for the application of the internal stains. Cervical 2 was used for the cervical third, Incisal Blue 2 for the proximal regions and Mamelon Orange 2 for the mamelons. As mentioned before, the selected internal stains were mixed with Bright.

Fig. 2f. Appearance of the veneers after the bake of the applied CERABIEN™ MiLai Internal Stains.

Fig. 2g. Final build-up to reach the desired shape of the veneers. LTx is the only material applied to the central and lateral incisors, while the canines are built up with LTx in the incisal and middle and LT1 in the cervical third.

Fig. 2h. Glazed and polished veneers on the model.

Images courtesy of Andreas Chatzimpatzakis.

CASE 3

ADVANCED APPROACH WITH GUM AREAS ON ZIRCONIA

In this case, a highly complex ten-unit bridge with gum parts in the anterior region had to be produced. The selected framework material was KATANA™ Zirconia HTML Plus (Kuraray Noritake Dental Inc.), which offers a multi-layered colour structure, an optimized translucency and the high flexural strength required for long-span bridges. The restoration was milled in an anatomically reduced design and the surface texture was optimized with rotating instruments before sintering [Fig. 3a]. After the final sintering procedure, the restoration had a favourably high translucency in the incisal region and a natural shade structure [Figs. 3b and 3c]. In the first step of the micro-layering procedure, the application of the CERABIEN™ MiLai Internal Stains was planned and carried out [Figs. 3d and 3e]. Subsequently, different layers of CERABIEN™ MiLai Porcelain were applied. The images 3f to 3h reveal which shades were combined and illustrate the procedure, while the outcome before and after the last bake is shown in Figures 3i to 3k. In the next step, the gum areas were completed using the CERABIEN™ MiLai tissue porcelains Tissue 4, 5 and 6 in the order and locations described in Figures 3l to 3o. In the final layer, Tissue 1 was mixed with ELT1 to imitate the labial frenulum and with LTx to create a smooth transition to the natural gingiva [Figs. 3p and 3q]. The final restoration is shown in Figure 3r.

Fig. 3a. Milled restoration after surface texturing.

Fig. 3b. Shade and translucency of the sintered zirconia restoration.

Fig. 3c. Highly translucent bridge on the model.

Fig. 3d. Chroma map for the application of CERABIEN™ MiLai Internal Stains.

Fig. 3e. Applying a mixture of Bright, Salmon Pink and Tissue Pink to the gum area.

Fig. 3f. Application of CERABIEN™ MiLai E2 to add translucency to the structure.

Fig. 3g. Application of Tx and a mixture of Tx and CCV-2 to individualize the cervical and incisal areas while boosting the translucency of the enamel in the middle and incisal third.

Fig. 3h. Adding a final layer of LT1 for additional translucency and opalescence.

Fig. 3i. Appearance of the ten-unit bridge before the bake – labial view.

Fig. 3j. Appearance of the ten-unit bridge before the bake – palatal view.

Fig. 3k. Appearance of the ten-unit bridge after the bake.

Fig. 3l. Application of small amounts of Tissue 5 …

Fig. 3m. … covered with a layer of Tissue 6 alternating with Tissue 5.

Fig. 3n. Following another bake, Tissue 5 is applied in the proximal areas.

Fig. 3o. How to combine Tissue 6 and Tissue 4 in the next layer.

Fig. 3p. How to complete the tissue layer with Tissue 1, locally mixed with ELT1 or LTx.

Fig. 3q. Restoration before the final bake.

Fig. 3r. Final ten-unit bridge ready for placement.

Images courtesy of Ioulianos Moustakis.

Article first published in Labline Magazine Issue 45, Spring 2022 edition.

4 Klinische casussen

Composieten met een universeel kleurconcept - een beperkt aantal kleuren die zonder kleurenschaal kunnen worden geselecteerd - vormen een duidelijke trend binnen de restauratieve tandheelkunde. Dankzij de specifieke aanpassingseigenschappen kunnen deze materialen bijdragen aan het stroomlijnen van restauratieve procedures en een vermindering van behandeltijden. Dit kan de werkdruk van de tandheelkundige praktijkbeoefenaar wat verlichten en goede resultaten bevorderen. Sommige gebruikers staan echter sceptisch tegenover een breed gebruik van deze materialen, vooral als het gaat om de restauratie van tanden in het anterieure gebied. Mogelijke redenen: een relatief hoge translucentie, die in bepaalde situaties de aparte toepassing van een blocker (of ondoorzichtige kleur) nodig maakt, of een te beperkt kleuraanbod.

Mijn persoonlijke ervaring heeft aangetoond dat CLEARFIL MAJESTY™ ES-2 Universal bij uitstek geschikt is voor een breed scala aan 1-kleur-restauraties van anterieure tanden. Dit product heeft een geweldige polijstbaarheid plus langdurig glansbehoud, en is leverbaar in slechts vier kleuren: een Universele kleur (U), aanvankelijk ontwikkeld voor posterieure restauraties, Universal Light (UL) en Universal Dark (UD) als de twee belangrijkste opties voor anterieure tanden en tot slot Universal White (UW) om alle bleachkleuren na te bootsen. In het algemeen kunnen deze opties alle vier worden toegepast in het anterieure en posterieure gebied. Aangezien het aanpassingsvermogen te danken is aan een propriëtaire lichtdiffusietechnologie en niet wordt geregeld via een verhoogde translucentie, is het gebruik van een blocker meestal niet nodig en kunnen zelfs grotere gedeelten heel onopvallend worden gerestaureerd.

De hierna volgende voorbeelden van klinisch casussen bieden, samen met het commentaar, wellicht houvast voor degenen die twijfelen over de juiste kleurkeuze in het anterieure gebied. De aanbevelingen en praktische tips zijn gebaseerd op mijn persoonlijke ervaring. Alle patiënten werden behandeld voor de sluiting van een diasteem of voor een vormaanpassing, maar de selectiecriteria gelden ook voor andere vormen van anterieure restauraties.

UNIVERSAL LIGHT: VOOR NATUURLIJKE RESULTATEN BIJ LICHTERE TANDEN

Deze jonge 35-jarige patiënt met microdontie meldde zich bij de praktijk omdat hij graag een mooier gevormd gebit wilde. Zijn gebit vertoonde vrijwel geen cariës, maar wél een gebrek aan mondhygiëne en tekenen van ontstoken tandvlees. Er was ook duidelijk sprake van een diepe beet. Na een professionele gebitsreiniging en advies over mondhygiëne werden de tanden hersteld met behulp van CLEARFIL MAJESTY™ ES-2 Universal in de kleur UL.

Afb. 1: Aanvankelijke situatie.

Afb. 2: Aanvankelijke situatie: diepe beet.

Afb. 3: Tanden gerestaureerd met composiet via de 1-kleurtechniek.

Afb. 4: Direct behandelingsresultaat.

Redenen voor de keuze van Universal Light:

- Voor jongere patiënten (tandkleuren A2 en lichter)

- Situaties waarin licht gemakkelijk door de composiet gaat (bijvoorbeeld Klasse III en Klasse IV)

Eigenschappen van Universal Light:

- Hoog lichtverspreidend effect

- Uitgebalanceerde translucentie

UNIVERSAL DARK: VOOR NATUURLIJKE RESULTATEN BIJ DONKERDERE TANDEN

Abrasie en vormcorrectie waren ook voor deze 58-jarige patiënt de belangrijkste redenen om een kosmetische tandheelkundige behandeling aan te vragen. Ze was ongelukkig met de aanblik van de anterieure tanden in haar bovenkaak, die tekenen van gebitsslijtage en verkleuring vertoonden. De gekozen aanpak was een composietveneerbehandeling met CLEARFIL MAJESTY™ ES-2 Universal in de kleur UD. De kleur werd geselecteerd op basis van de indicatie en de ietwat donkerder kleur van het natuurlijke gebit van de patiënt.

Afb. 5: Klinische beginsituatie.

Afb. 6: Resultaat van de behandeling.

Redenen voor de keuze van Universal Dark:

- Voor oudere patiënten (tandkleuren A3 en donkerder)

- Situaties waarin licht gemakkelijk door de composiet gaat (bijvoorbeeld Klasse III en Klasse IV)

Eigenschappen van Universal Light:

- Hoog lichtverspreidend effect

- Uitgebalanceerde translucentie

UNIVERSAL: ALTIJD ALS EEN HOGE TRANSLUCENTIE IS GEWENST

Als de te restaureren tanden worden omringd door uitgebreide niet-verkleurde gebitsstructuren - wat kan voorkomen bij Klasse I-, II- en V-caviteiten - kan het gebruik van CLEARFIL MAJESTY™ ES-2 Universal in de kleur U een optie zijn. De tanden van de 28-jarige patiënt die zich had gemeld voor een diasteemsluiting, hadden een relatief lage translucentie en verschillende kleuren als gevolg van roken en overmatige koffieconsumptie. Aangezien de composiet alleen in glazuurgedeelten werd aangebracht, leek de relatief hoge translucentie van de kleur Universal in deze casus een voordeel te zijn.

Afb. 7: Klinische beginsituatie.

Afb. 8: De nieuwe smile van de patiënt.

Redenen voor de keuze van Universal:

- Uitgebreide aanwezigheid van onderliggende of omringende tandstructuren

- Gemiddelde lichtverspreiding gewenst

Eigenschappen van Universal:

- Hoge translucentie

- Gemiddeld lichtverspreidend effect

UNIVERSAL WHITE: VOOR ALLE PATIËNTEN DIE VRAGEN OM EEN BLEACHEFFECT

Voor alle behandelingen waarbij een bijzonder lichte tandkleur nodig is - bijvoorbeeld kinderen of patiënten met gebleekte tanden, of patiënten die vragen om een restauratie met een bleacheffect - komt CLEARFIL MAJESTY™ ES-2 Universal in de kleur UW als eerste optie in aanmerking. De hieronder getoonde jonge 28-jarige patiënt had gevraagd om een diasteemsluiting compleet met een vorm- en kleurcorrectie; ze wilde een lichtere en meer aantrekkelijke smile.

Afb. 9: Klinische beginsituatie.

Afb. 10: Een vorm- en kleurcorrectie waren gewenst bij deze casus.

Afb. 11: Resultaat van de behandeling ...

Afb. 12: … die zorgde voor de prachtige smile die de patiënt zo graag wilde.

Redenen voor de keuze van Universal White:

- Behandelingen die vragen om een uitzonderlijk hoge helderheid of value

- Restauraties van melktanden

- Restauraties van gebleekte tanden

Eigenschappen van Universal White:

- Uitgebalanceerde translucentie

- Hoog lichtverspreidend effect

CONCLUSIE

Eén universele composiet, vier kleuren: in het geval van CLEARFIL MAJESTY™ ES-2 Universal is het assortiment zonder meer voldoende voor 1-kleurestauraties, zelfs in het esthetisch veeleisende anterieure gebied. Tandheelkundige praktijkbeoefenaren kunnen fantastische restauraties realiseren dankzij eigenschappen zoals een mooi aanpassingseffect, ideale polijstbaarheid en langdurig glansbehoud. De kleur kan in principe worden bepaald op basis van slechts enkele criteria, dus zonder een complexe kleurenschaal; daarmee wordt de algehele restauratieprocedure relaxter en efficiënter. Bovendien hoeft er - met slechts vier kleuren en doorgaans zonder de noodzaak van een blocker - minder materiaal op voorraad te worden gehouden; het voorraadbeheer wordt dus ook vergemakkelijkt.

Dentist:

JUSUF LUKARCANIN

Dr. Jusuf Lukarcanin is een Certified Dental Technician (DCT) en tevens Doctor of Dental Science (DDS). Hij is in 2011 als Master afgestudeerd aan de Tandheelkundige Faculteit van de Ege Universiteit in het Turkse Izmir. In 2017 voltooide hij zijn doctoraalstudie bij de faculteit Restauratieve Tandheelkunde van die universiteit. Tussen 2012 en 2019 was dr. Lukarcanin chef de clinique en general manager van een privékliniek in Izmir.

Tussen 2019 en 2020 werkte hij als specialist Restauratieve Tandheelkunde bij het Tinaztepe Galen Hospital; van 2020 tot 2022 bekleedde hij diezelfde functie bij het Medicana International Hospital in Izmir. Momenteel is hij eigenaar van een privékliniek voor esthetiek en cosmetiek in Izmir.

Discover a detailed walkthrough of an advanced shade reproduction technique with this comprehensive guide by DT Tomáš Forejtek. Tailored for professionals working with CERABIEN™ ZR ceramics (Kuraray Noritake Dental Inc.) and the eLAB protocol, this case study provides step-by-step insights into achieving exceptional results, from documentation to shade selection and framework design to final polish. Whether you are refining your craft or exploring new methods, this resource is a valuable addition to your toolkit.

THE ART OF RESTORING SMILES: MASTERING THE CHALLENGE OF A SINGLE CENTRAL INCISOR

Restoring a single maxillary central incisor is possibly the biggest challenge a dental technician can face in everyday work. Especially when a patient is young, it is extremely important to restore her or his smile to its original beauty. Any restoration that is perceivable as such might have a negative impact on their self-confidence and quality of life even in the long term.

A STORY OF JOY AND DESPERATION

Take Ioanna, a 14-year-old girl who presented in her dental office in a state of desperation. In the hours before, she had been floating on cloud nine: Her favourite band performed in Cyprus for the first time and she had managed to buy tickets for herself and her best friend. Thrilled, they had arrived at the concert, the band started playing and the crowd danced to the music. It felt like this was going to be the best day of her life. At the time the band played its most popular song, people were delirious, jumping up and down in ecstasy. Between all the exuberant dancing and laughing, however, Ioanna suddenly was hit by a strong push. She fell, her face hitting something hard – a seat in front of her. Pain froze time and it took a few seconds before she understood what had happened: Tasting blood in her mouth, she explored her teeth with her tongue and realized that one of her central incisors had fractured.

AFFECTING THE QUALITY OF LIFE

This is one of the many touching stories we listen to every day. A fall during a concert, a push at somebody’s birthday party, a car accident: There are many incidences that can ruin a young, beautiful smile. By paying attention to the involved patients and their stories, one will come to realize how strongly some of them are affected by all this. They cover their mouths when they laugh or hold back their smiles.

Any dental technician who is committed to restoring their lost smile in the best possible way is probably aware of the impact his or her work can have and the responsibility coming with it: A Beautiful result will restore not only their smile, but also their self-confidence, will let them start laughing happily, expressing themselves comfortably and simply enjoying social interaction again (Figs. 1 to 5). Compromised outcomes, on the other hand, might have the opposite effect. Being aware of this role should be every technician’s motivation to become better day by day. Evolve for these moments, when our work brings tears of joy to our patients.

Fig. 1. Layering sketch for the restoration of a fractured central incisor in three layers: Layer one.

Fig. 2. Layering sketch for the restoration of a fractured central incisor in three layers: Layer two.

Fig. 3. Layering sketch for the restoration of a fractured central incisor in three layers: Layer three. After the first bake, small details were integrated, followed by a second bake. Finally, the restoration was finished with CERABIEN™ ZR FC Paste Stain and Glaze.

Fig. 4. Treatment outcome able to restore not only the smile, but also the self-confidence of the young girl.

Fig. 5. Immediately after cementation of the restoration, the restoration is barely identifiable, only the soft tissue needs some time for recovery.

ASPECTS TO BE CONSIDERED

But how to proceed in restoring single central incisors in the best possible way? The success of this type of restoration is hidden in the shape, which is the most difficult part. Managing to create a natural morphology is more than half the battle. The other important part is colour. The key to reproducing colour is in understanding how the utilized porcelains work. It is all about light reflection, absorption, translucency and opalescence, value and characteristic details. The more you gain experience and understand the optical properties of teeth and ceramics, the better your outcomes will be. Support is offered by a camera, a macro lens and a twin flash, which are used to capture and analyse the intraoral situation. For an initial analysis and understanding of shape and colour, I like to see the patients in my dental laboratory. Feeling the colour helps to develop the most realistic picture of what needs to be created. The key to successful realisation of the plan just developed is the use of reliable, easy-to-handle materials – in my case KATANA™ Zirconia and CERABIEN™ ZR Porcelains (both Kuraray Noritake Dental Inc.).

POSSIBLE STEPS

The first thing to focus on when starting to produce an anterior restoration – like in the case presented in figures 6 to 14 – is the correct value of the tooth. As soon as the framework or base is produced in the right value, you need to place what you see. Does the adjacent tooth show mamelons, traces of blue and orange? Those characteristics simply need to be observed and copied. There is no need to create something fancy. The tricky part is to use the available space reasonably. When there is plenty of space for the porcelain, it may be challenging to keep the value of the framework and avoid a greyish appearance. Depending on the die colour, age of the patient, natural surface texture and space available, an appropriate layering approach and finishing technique may be selected.

Fig. 6. Replacement of an anterior crown: Prepared tooth with severe discolouration. The adjacent central incisor has a special shape and vivid inner colour structure.

Fig. 7. Framework made of KATANA™ Zirconia ML in the shade A3. The target shade being A3.5, a quite opaque material was selected in a slightly brighter shade to achieve the required masking effect.

Fig. 8. Single-bake layering procedure: Application of CERABIEN™ ZR Opacious Body, …

Fig. 9. … Cervical Body, …

Fig. 10. … Body and Transitional Body.

Fig. 11. Incisal cut-back …

Fig. 12. … and creation of the mamelon structure.

Fig. 13. Application of Aqua Blue 1 …

Fig. 14. … followed by T Blue …

Fig. 15. … and Luster Porcelains.

Fig. 16. Halo effect created with Body.

Fig. 17. Treatment outcome. (After a first bake followed by minor adjustments, a second bake, surface texturing and glazing with CERABIEN™ ZR FC Paste Stain Clear Glaze.)

CONCLUSION

Creating a single central takes us out of our comfort zone. By paying attention, observing the adjacent teeth carefully and using materials we really understand, it is possible to meet or exceed our patients’ expectations. While specific tools like cameras and experience with the utilized materials offer support in producing predictable outcomes, my main credo is “If you want things around you to change, you must first change yourself”. For continued improvement, it is thus necessary to focus on professional growth and advancement. With the right mentors who will teach us the secrets of stratification and inspire and motivate us to continue advancing, it becomes easier to restore the smiles and self-confidence of our patients every time they need us to.

Acknowledgements

Special thanks go to the dental practitioners who treated the patients presented above – Andreas Skyllouriotis DDS, MSD, Surgically-Trained Prosthodontist, and Theo Odysseos, DDS, Diplomate, American Board of Oral Implantology / Implant Dentistry.

Case by CDT Mathias Berger, France

Every patient is unique. Their specific backgrounds, functional needs and aesthetic demands need to be respected in any prosthodontic treatment plan. However, the importance of an individual treatment approach increases with the number of teeth to be replaced: After all, the impact of the restorations on facial aesthetics and on the patient’s quality of life is never greater than when all teeth are missing. Fortunately, adequate dental materials and techniques are available for a patient-centered, individual approach, no matter what challenges need to be overcome.

A patient with bruxism

In the present case, an elderly male patient with bruxism was in need of a new maxillary denture. Since the placement of five implants in the maxilla, he had no proprioception in this jaw. This lack of sensation had an impact on the overdenture to be produced: material and design needed to be carefully selected in a way that it would withstand uncontrolled chewing forces. As technical complications are easier to repair than biological complications, the overdenture should not be unbreakable – instead, the replacement of single units should be easily manageable.

Two-part denture design

The solution was a two-part design with a milled bar consisting of the gum area and tooth abutments (fig. 1) combined with single crowns. The material of choice for the bar was KATANA™ Zirconia HTML Plus (Kuraray Noritake Dental Inc.) with a uniform flexural strength of 1,150 MPa throughout the disc, while the single crowns were milled from KATANA™ Zirconia YML that offers natural translucency and strength gradation. While a monolithic design was selected for the posterior crowns, the six crowns for the anterior region received a micro-cutback for aesthetic micro-layering with CERABIEN™ ZR Porcelain. The shade scheme for individualization of the anterior crowns is shown in fig. 2. In a nutshell, customization was performed with the Internal Stains Cervical 1, Grayish Blue, Dark Grey and A+. The finishing layer on the incisors was created mainly using LT0 materials with some CCV-3 on the cervical and LT Natural on the mesial and distal lobes. On the canines, LT1 was used instead of LT0. The posterior crowns were merely finished with liquid ceramics (CERABIEN™ ZR FC Paste Stain, Kuraray Noritake Dental Inc.).

Fig. 1. Sintered bar milled from KATANA™ Zirconia HTML Plus.

Fig. 2. Chroma map for micro-layering in the anterior region.

Fig. 3 shows the finished single crowns with their individual, age-appropriate shade effects on the sintered bar. After checking the fit of the crowns, the gum areas of the bar were individualized using CERABIEN™ ZR Tissue Porcelain (fig. 4). Subsequently, the crowns were luted to the zirconia abutments (fig. 5), leaving screw access holes in aesthetically uncritical positions (fig. 6). The final overdenture ready for try-in is shown in fig. 7. Due to an excellent fit on the implants (fig. 8), it was possible to immediately fix the overdenture with the screws, close the access holes with composite and discharge the patient. The final appearance is shown in fig. 9.

Fig. 3. Finished crowns on the sintered bar.

Fig. 4. Bar with individualized gum areas.

Fig. 5. Placement of the central incisor crowns on the bar.

Fig. 6. Occlusal screw access hole in the finished overdenture.

Fig. 7. Overdenture ready for try-in.

Fig. 8. Intraoral try-in of the aesthetic overdenture.

FINAL SITUATION

Fig. 9. Treatment outcome.

CONCLUSION

This patient case is a good example of how important it is to respect the patient’s background, age and specific demands when producing dental restorations. Thanks to the great variety of restorative materials with different mechanical and optical properties available, it is possible to create suitable prosthetics for virtually every patient. However, for this purpose, it is important to stay up to date regarding new products launched and techniques developed. This way, it is often even possible to create beautiful and durable solutions in a simplified and efficient procedure such as micro-layering on innovative zirconia with a high aesthetic potential.

Dentist:

CDT MATHIAS BERGER

Case by Dr. Enzo Attanasio

The selection of the restorative material is a crucial step in prosthodontics. Hybrid ceramics offer a range of properties well-suited for various therapeutic situations, both in the presence of vital teeth and of endodontically treated teeth. Using the example of a clinical case, this article will explore the advantages associated with the use of hybrid ceramics in a cracked tooth syndrome scenario.

INITIAL SITUATION

The affected tooth in this case was a mandibular right second premolar (45 according to the FDI notation) with an old amalgam restoration (Figs. 1 and 2). The patient experienced pain upon chewing (specifically upon release). Clinically, there were visible horizontal and vertical crack lines. The tooth was vital and showed no signs of pulpal pathology. It was decided to replace the amalgam restoration and restore the tooth with an overlay made of the hybrid ceramic KATANA™ AVENCIA™ Block. There were two main reasons for this decision. First, whenever root canal treatment would be necessary in the future, the hybrid ceramic material would facilitate endodontic access cavity preparation (compared to any other ceramic material) and subsequent restoration with composite filling material. Second, hybrid ceramics offer greater resistance and improved mechanical properties compared to composite filling materials applied in an incremental layering technique.

Fig. 1. Initial situation: Occlusal view.

Fig. 2. Initial situation: Buccal view.

PREPARATION AND IMMEDIATE DENTIN SEALING

To remove the amalgam restoration and weakened surrounding tooth structure, the occlusal surface of the tooth was reduced by approximately 2 mm. For a smooth colour transition between the tooth and the restoration, the preparation outline was created at the level of interproximal boxes with a vestibular inclined plane (Fig. 3). Subsequently, Immediate Dentinal Sealing (IDS) was carried out (Figs. 4 to 10). This technique involves the use of a universal adhesive like CLEARFIL™ Universal Bond Quick, which is applied to the preparation without prior etching of the peripheral enamel. In the second step, a highly filled flowable composite is applied. In the present case, the material of choice was CLEARFIL MAJESTY™ ES Flow Super Low, applied in a thickness of just 0.5 mm. The preparation was refined using ultrasonic instrumentation: Sonic tips SFM7 and SFD7 (Komet Dental) for refining the boxes; SFD1F and SFM1F (Komet Dental) for margins and steps. Sharp edges were rounded with abrasive discs and then polished with fine polishers. It is crucial that the residual occlusal thickness (prosthetic space) is 1.5 mm, as required by the selected material.

Fig. 3. Prepared tooth structure prior to immediate dentin sealing.

Fig. 4. IDS: Application of the universal adhesive.

Fig. 5. IDS: Light curing of the adhesive layer.

Fig. 6. Thin layer of flowable composite applied to the preparation.

Fig. 7. Contouring, …

Fig. 8. … rounding off sharp edges …

Fig. 9. … and polishing of the sealed surface with dedicated instruments.

Fig. 10. Sealed tooth preparation ready for impression taking.

FROM SCANNING TO TRY-IN

Following digital scanning with the intraoral scanner Primescan™ (Dentsply Sirona), MDT Daniele Rondoni produced the restoration (Figs. 11 and 12). The cementation process involves an initial try in phase to assess the marginal fit of the overlay and the contact areas. Testing occlusion at this stage could be risky as it may lead to fracture of the restoration in case of excessive premature contacts. After try-in (when carried out without rubber dam), the restoration may be contaminated by blood, saliva, or glycerin gel used for the evaluation of fit and aesthetics. Therefore, it is necessary to clean the restoration before proceeding with adhesive phases. The use of a cotton pellet soaked in alcohol is an option, a cleaning agent like KATANA™ Cleaner may be even better as it chemically cleans the restoration and eliminates the contaminants.

Fig. 11. Hybrid ceramic overlay on the printed model.

Fig. 12. Separate overlay.

CONDITIONING OF THE TOOTH AND THE RESTORATION

Afterwards, the restoration was sandblasted (as recommended for most hybrid ceramics) with 50 μm aluminum oxide using AquaCare (Akura Medical) (Fig. 13), and then immersed in distilled water in an ultrasonic bath for 5 minutes. Meanwhile, rubber dam was placed over the entire sextant, the build-up was sandblasted like the intaglio of the overlay and a phosphoric acid etchant (Ultra Etch, Ultradent) was applied to the enamel, rinsed off and the area dried (Figs. 14 to 17). The clean restoration was subsequently conditioned with a silane containing 10-MDP (CLEARFIL™ Ceramic Primer Plus, Kuraray Noritake Dental Inc.) according to the manufacturer’s instructions (Fig. 18). What followed was the application of the universal adhesive (CLEARFIL™ Universal Bond Quick) to the intaglio of the overlay and to the preparation and light curing on both sites (Figs. 19 and 20). One of the advantages of universal adhesives compared to three-step adhesive systems is their minimal film thickness, which does not compromise the fit of the restoration.

It is important to protect adjacent teeth with metal matrix strips during adhesive phases to provide for proper fitting. These elements do not create operational difficulties, but serve their purpose: After restoration placement, the composite or cement used for placement will be easily removable from the mesial and distal surfaces of the adjacent teeth, as they are free of adhesive.

Fig. 13. Sandblasting of the overlay …

Fig. 14. … and the tooth structure.

Fig. 15. Selective etching of the enamel, …

Fig. 16. … followed by thorough rinsing. Adjacent teeth are protected by a metal matrix strip.

Fig. 17. Tooth structure after selective etching, rinsing and drying.

Fig. 18. Silane application.

Fig. 19. Application of the universal adhesive into the overlay.

Fig. 20. Treatment of the tooth structure with the universal adhesive.

DEFINITIVE PLACEMENT

In the present case, a heated composite paste (heated to a temperature of 55 °C) was extruded into the restoration, which was then placed by applying slow, gradual, and strong pressure (Figs. 21 and 22). Excess composite was removed with a scaler in the buccal and lingual areas and floss (e.g. SuperFloss®, Oral-B) in the interproximal areas. Several pressurization phases were performed until no more composite was observed at the tooth-restoration interface.

Fig. 21. Heated composite paste used for definitive placement.

Fig. 22. Restoration placed under rubber dam isolation.

Then, the composite was polymerized for 30 seconds from the buccal and lingual sides with two curing lights, before applying glycerin gel to the margins and polymerizing from occlusal for another minute (Fig. 23). If thorough attention is given to removing excess composite during placement phases, subsequent finishing steps will be quick and easy (Figs. 24 to 27). Finishing and polishing of the interproximal areas was accomplished with an EVA handpiece and 3M™ Sof-Lex™ Finishing Strips (3M). For finishing of the buccal and lingual areas, a medium-grit, flame-shaped diamond bur (diameter 14/16) was used. Finally, the margins should be polished using composite polishers like TWIST™ DIA for Composite (Kuraray Noritake Dental Inc.). After the local anesthesia wears off, one should observe the cessation of pain symptoms, as seen in the present case. The treatment outcome is displayed in Figures 28 and 29.

Fig. 23. Light curing through a layer of glycerin gel blocking the oxygen.

Fig. 24. Finishing of the buccal and lingual margin with a medium-grid, flame-shaped diamond bur.

Fig. 25. Finishing of the interproximal areas with EVA handpiece (fine grain).

Fig. 26. Checking the occlusal contacts.

Fig. 27. Occlusal polishing.

FINAL SITUATION

Fig. 28. Treatment outcome – buccal view.

Fig. 29. Treatment outcome – occlusal view.

CONCLUSION

For posterior teeth restored with amalgam and a significant level of destruction, restoration replacement with hybrid ceramic overlays can be a great option. Mechanical material properties are usually superior to those of layered composites, processing is possible chairside or labside and comparatively quick (no firing required), while the clinical placement procedure is similar to that involved in placing glass ceramics – with the major difference of sandblasting instead of etching the intaglio of the restoration. One of the most important benefits of hybrid ceramics over glass ceramics, however, is the ability to modify the restoration whenever desired. Endodontic access cavities are easily prepared and closed with composite, contact points are quickly adjusted and the surface is polished or re-polished in next to no time. Moreover, the wear properties are similar to those of tooth structure and patients are happy about a natural touch and feel. The aesthetic properties are quite impressive, too.

Clinical case by Dr. Frank Heldenbergh

The advancements in zirconia in contemporary dentistry nowadays allow for a wider range of applications, including in the anterior sector, and for chairside production using dedicated CAD/CAM systems. Even without a cutback, KATANA™ Zirconia Block (STML), combined with CERABIEN™ ZR FC Paste Stain (both Kuraray Noritake Dental Inc.), offer an extremely satisfactory aesthetic solution.

In the present patient case, the materials were chosen to replace old PFM crowns on the maxillary central incisors. The planned treatment was in accordance with the patient's wishes, and carried out in a single appointment.

CASE DESCRIPTION

The patient asked for a replacement of the existing crowns on the two maxillary central incisors (teeth 11 and 21, FDI notation). The porcelain-fused-to-metal (PFM) restorations had been in place for about thirty years (Figure 1). She desired aesthetic improvements and slight repositioning of these two teeth.

TREATMENT PLAN

In agreement with the patient, it was decided to perform the entire procedure in one appointment: removal of the existing crowns, digital impressions, production, and bonding of new restorations. The periodontium was healthy with no bleeding. The only uncertainty was whether the existing crowns were cemented onto inlay-cores or if they were Richmond crowns. A preliminary silicone impression was taken as a precautious measure: in case something unexpected prevented the new crowns from being bonded during the session, it would be easily possible to produce temporary crowns.

Fig. 1. Initial clinical situation.

TREATMENT

Using a diamond bur followed by a tungsten carbide bur, the existing crowns were removed, revealing that they indeed were Richmond crowns. Because the anatomy of the intra-radicular posts clearly contraindicates an attempt to remove these posts, it was decided to trim the crowns to transform them into inlay cores rather than risk further damage. The corono-peripheral preparations were reworked at the same time. One of the major challenges was related to the necessity of masking the metal of the transformed coronal-radicular reconstructions. Luckily, the space available was sufficient for the production of full zirconia crowns with a significant thickness (Figure 2). The target shade of the crowns was chosen in consultation with the patient (Figure 3).

Fig. 2. Situation after removal of the existing restorations.

Fig. 3. Shade determination using a shade tab: A2 was the appropriate shade.

Subsequently, impressions were taken using and intraoral scanner, the virtual models were checked and the crowns designed, considering the patient's request to have her two incisors slightly retracted (Figures 4 and 5).

Fig. 4. Virtual models of the patient’s teeth with the newly designed crowns, revealing the space available for a slight retraction.

Fig. 5. Designing of the two crowns.

The two crowns were milled from KATANA™ Zirconia Block 14Z A2 (Figure 6). A quick reminder: unlike lithium disilicate, zirconia prosthetic parts cannot be tried in immediately after milling, as they are around 20 percent larger than their final size after sintering. Final sintering was performed within about 18 minutes using the furnace SINTRA CS (ShenPaz Dental Ltd). After this process, the crowns may be tried on to check their fit, shape, shade and optical integration.

Fig. 6. Milled crowns in the CAD/CAM blocks.

For finishing of the restorations, different options are available. In this case, we decided not to limit ourselves to mechanical polishing of the prosthetic parts, as zirconia does not fluoresce like natural teeth. To add fluorescence as an optical feature, the surface was lightly stained and glazed with CERABIEN™ ZR FC Paste Stain (Figure 7).

Fig. 7. Crowns in the furnace after staining and glazing with liquid ceramics.

After firing, the two incisor crowns were tried in again using a try-in paste corresponding to the chosen resin cement system (PANAVIA™ V5, Kuraray Noritake Dental). In this way, the final appearance was simulated to validate the shade of the cement. The intaglio surfaces of the crowns were then sandblasted before applying CLEARFIL™ CERAMIC PRIMER PLUS as the restoration primer. The prepared teeth were treated with KATANA™ Cleaner (Kuraray Noritake Dental Inc.) to decontaminate the surface from proteins in saliva and possibly blood. Those clean surfaces are ideal for bonding. After thorough rinsing and drying, PANAVIA™ V5 Tooth Primer (containing MDP monomer for bonding with the hydroxyapatite and metal of the preparation) was applied according to the manufacturer’s instructions (Figure 8).

Fig. 8. Selected cementation system and try-in.

Subsequently, PANAVIA™ V5 Paste was applied into the first crown, which was then seated, followed by tack curing (brief photopolymerization for three to five seconds), excess removal and final light curing from all sides.

The procedure was then repeated for the second maxillary central incisor. The result instantly satisfied the patient, both in terms of aesthetics (adaptation, position of the new crowns, mimicry) and the comfort provided (Figures 9 and 10).

Fig. 9. Crowns immediately after placement.

Fig. 10. Aesthetically pleasing and comfortable result.

At a recall after four months, soft tissue conditions were ideal and the patient was happy with the outcome (Figures 11 to 13). The selected zirconia had nice optical properties, masking of the metal posts was successful and the natural surface texture contributed its share to a nice overall picture. The retracted position of the teeth was also perceived positively by the patient, while comfort and function were excellent.

DISCUSSION

Although lithium disilicate has so far been considered the material of choice for prosthetic work in the anterior region, zirconia is nowadays proving to be an extremely satisfactory alternative from every point of view: milling, strength, aesthetics, assembly (among other things, no hydrofluoric acid is required for bonding). KATANA™ Zirconia Blocks (STML) with a multi-layered colour structure in a single 4Y-TZP zirconia block, combined with CERABIEN™ ZR FC Paste Stain, offer a remarkable solution. This applies to treatments around the replacement of existing crowns as well as first-line treatments with less invasive preparations (verti-prep) than those required by other types of ceramics.

Fig. 11. The patient’s smile at a recall after four months.

Fig. 12. Great optical integration.

Fig. 13. Natural surface texture contributing to success Control pictures after four months taken by Emmanuel Charleux.

Case by Aleksandra Łyżwińska DMD, Warsaw, Poland

Dental injuries can be stressful for patients, parents of pediatric patients, and dentists alike. The following tips offer support in turning the treatment of crown fractures into a simple, quick and predictable procedure. In the case described, we opted for a reattachment of fractured crown fragments.

YOUNG PATIENT WITH A FRACTURED CENTRAL INCISOR

A 16-year-old patient presented immediately after an accident. Her maxillary left central incisor was fractured, involving half of the coronal enamel and dentin (Fig. 1). The pulp was not involved, but the fracture line was quite close to the pulp (Fig. 2). After examination and radiographic evaluation, the patient was anesthetized. When placing the rubber dam, it tore between the left central and lateral incisor (Figs. 3 and 4). Due to the patient’s young age and limited willingness to cooperate, the decision was made to proceed without replacing the rubber dam. This was expected to work well in this specific region due to the limited flow of saliva from the palate and a low associated risk of contamination.

Fig. 1. Fractured maxillary left central incisor at the day of the accident.

Fig. 2. Occlusal view of the maxillary anterior teeth with the pulp of the fractured central incisor shining through.

Fig. 3. Rubber dam placed and torn between the left central and lateral incisor.

Fig. 4. Occlusal view of the teeth isolated with rubber dam.

REMOVAL OF UNSUPPORTED ENAMEL PRISMS

In order to provide for a high-quality bond and natural aesthetics, unsupported enamel prisms should be removed. As the use of burs might be too invasive (removing too much structure) and thus hinder the alignment of crown fragments, air-abrasion with 50 μm alumina particles was the method of choice. To avoid iatrogenic pulp exposure, the deepest part of the affected tooth was protected with a colored flowable composite before sandblasting (Fig. 5). The adjacent teeth were protected using a metal strip (Fig. 6). Several seconds of air abrasion were sufficient to remove the enamel prisms and obtain a homogeneous enamel surface (Fig. 7). Subsequently, the colored flowable composite was removed from the dentin surface and the tooth fragment was treated in the same way.

Fig. 5. Preparations for sandblasting: Dentin area near the pulp protected with flowable composite.

Fig. 6. Protection of the adjacent teeth with a metal strip.

Fig. 7. Homogeneous enamel surface after air abrasion.

JOINING OF THE FRAGMENT WITH THE REMAINING TOOTH STRUCTURE

After air-abrasion treatment, the fit of the tooth and the fragment was checked and approved (Fig. 8). To improve retention of the fractured crown portion, it was bonded to a micro applicator using composite resin. Alternatively, prefabricated prosthetic carriers may be used. Then, selective etching of the enamel was performed on the tooth and the fragment (Figs. 9 and 10). During this procedure, the adjacent teeth were protected with a celluloid strip (Fig. 11). To better adapt the strip to the distal surface, a curved wedge was placed interproximally (Fig. 12).

The bonding system of choice was CLEARFIL™ SE Bond 2 (Kuraray Noritake Dental Inc.). After applying this adhesive to the tooth and the fragment (Fig. 13), a small portion of CLEARFIL MAJESTY™ ES Flow Super Low (Kuraray Noritake Dental Inc.) in the shade A2 was applied to the part of the fragment treated with adhesive.* After careful repositioning of the fragment and while holding it in place with the micro applicator, the composite was light cured.

Fig. 8. Perfect fit of the fragment to the tooth.

Fig. 9. Selective etching of the enamel on the tooth …

Fig. 10. … and the fragment.

Fig. 11. Position of the wedge …

Fig. 12. … used for better adaptation to the distal surface.

Fig. 13. Fragment treated with CLEARFIL™ SE Bond 2 PRIMER and BOND, which were both carefully air-dried, while the Bond was also light cured.

Fig. 14. Fragment back in place.

Fig. 15. Occlusal view of the teeth with the reattached fragment perfectly fitting the mould.

EXCESS REMOVAL AND POLISHING

Excess composite was removed with a scalpel blade and abrasive discs. The entire restoration was then polished using TWIST™ DIA for Composite (Kuraray Noritake Dental Inc., Fig. 16). A nice optical integration was obtained immediately after finishing due to fact that the fragment was stored in water during the waiting time and treatment. As observed with teeth isolated with rubber dam during treatment, teeth undergo dehydration outside the oral cavity. The effect is much stronger in the latter setting, making a fragment become chalky white. By keeping the fragment in water, dehydration is limited to a minimum and it is possible to properly evaluate the aesthetic outcome. This has a positive impact on patient satisfaction. In the present case, the fragment and the tooth structure had a similar appearance, both showing a slightly increased brightness as a result of manipulation under rubber dam or in the air, respectively.

Fig. 16. Immediately after polishing, the fragment has almost the same brightness as the tooth thanks to water storage. A slight dehydration effect is visible.

TREATMENT OUTCOME

To achieve optimal aesthetics and long-lasting gloss, the composite was repolished one week later (Fig. 17). This was accomplished with a light blue high-shine rubber polisher of the TWIST™ DIA for Composite system, followed by polishing with diamond paste and a goat hair brush.

Fig. 17. Treatment outcome after one week.

Teeth previously isolated with a rubber dam and the fractured crown fragment had undergone rehydration and returned to their natural colour. The colour adaptation is satisfactory. Harmonious light reflections on the labial surface of the treated tooth a beautiful, natural shine have made the fracture site nearly invisible. In addition to aesthetic value, good therapeutic results were also achieved - the tooth responds appropriately to stimuli and is pain-free.

CONCLUSION

The described approach is a valuable treatment option for anterior trauma cases with relatively large fragments that are still available. By reattaching the natural structure, the need for complicated and time-consuming multi-shade layering and free-hand modeling is eliminated, while all the remaining natural tooth structure is saved. Instead of preparing the tooth, a removal of the unsupported enamel prisms and roughening of the surface is absolutely sufficient. Key elements for a great optical integration and long-lasting success are the proper use of a high-performance adhesive as well as the selection of a composite that has the ability to properly blend into its environment and offers a nature-like gloss retention. The selected materials offer precisely these features, so that the great outcome may be expected to last.

*CLEARFIL MAJESTY™ ES Flow Super Low is indicated for cementation purposes. The cementation of tooth fragments, however, is not explicitly mentioned in the instructions for use. The decision to use the product in this context was made by the dental practitioner in charge of the treatment.