Dumitru Leahu

Case by Dumitru Leahu

INTRODUCTION

Complex anterior rehabilitations require careful control of shape, colour and optical properties. In this implant-supported restoration, a KATANA™ Zirconia YML framework was combined with CERABIEN™ ZR and CERABIEN™ MiLai (all Kuraray Noritake Dental Inc.) to achieve the desired aesthetic outcome.

FRAMEWORK DESIGN

A 1mm vestibular cut-back and a free zirconia incisal third were incorporated into the framework design to provide sufficient space for the ceramic layers. KATANA Zirconia YML was used for the implant-supported restoration (Fig. 1). The sintering temperature was 1,550 °C.

Fig. 1. Framework design with a 1mm vestibular cut-back and a free zirconia incisal third.

MATERIAL:

KATANA Zirconia YML

CERABIEN ZR BASE BUILD-UP

The first ceramic firing with high-fusing CERABIEN ZR porcelain was used to create well-defined and stable concavities with sufficient value and brightness (Fig. 2). The materials used were 0.5 NW Body, Enamel 1, LTx, Tissue 3 and Tissue 4. The firing temperature was 940 °C.

Fig. 2. Base build-up with CERABIEN ZR using 0.5 NW Body, Enamel 1, LTx, Tissue 3 and Tissue 4.

MATERIAL:

CERABIEN ZR

INTERNAL CHARACTERISATION

Internal characterisation was performed with CERABIEN MiLai internal stains (Fig. 3). Cervical 2 + Bright (mixed in a ratio of 40/60), White + (A+) + Bright (50/10/40), and Tissue Red + Bright (60/40) were applied as indicated. The firing temperature was 700 °C. The internal stains were used to reproduce the internal anatomy and characterisation of the restoration and to support the colour match with the natural teeth (Figs. 4 to 6).

Fig. 3. Internal characterisation with CERABIEN MiLai internal stains.

Fig. 4. Detail of the incisal characterisation. (left)

Fig. 5. Detail of the cervical characterisation. (right)

Fig. 6. Intraoral reference for matching the restoration to the natural teeth.

FINAL BUILD-UP WITH CERABIEN MILAI

The bridge was finished with low-temperature CERABIEN MiLai porcelain. LT1, LTx and ELT₁ were used for the final build-up (Fig. 7). The firing temperature was 780 °C. Tissue 1 was subsequently applied to create the final gingival shape (Fig. 8). This time, the firing temperature was 740 °C. Figures 9, 10 and 11 show the finished restoration extraorally, at intraoral try-in and after definitive placement on the implants.

Fig. 7. Final ceramic build-up with LT₁, LTx and ELT₁.

Fig. 8. Gingival build-up with Tissue 1.

Fig. 9. Finished implant-supported bridge.

Fig. 10. Final restoration at try-in.

Fig. 11. Final intraoral result.

CONCLUSION

The presented hybrid approach combines the advantages of high- and low-fusing porcelains for the aesthetic individualisation of anterior zirconia restorations. The high-fusing CERABIEN ZR porcelain can be used to establish the basic morphology and optical foundation before proceeding with lower-temperature characterisation and final layering. As the previously fired CERABIEN ZR layers remain stable during the subsequent CERABIEN MiLai firings, the restoration can be further individualised while maintaining the structures already established.

UNCOMPROMISED.
UNMATCHED.
YOURS.

Case by DT Dumitru Leahu

Aesthetically motivated restorative treatments are steadily gaining popularity. White teeth following the American example, ideal proportions and a natural surface texture is what many patients request when presenting at a cosmetic dental practice. In those cases, the particular challenge is in selecting a treatment that enables the restorative team to meet the patient’s expectations without harming the otherwise healthy tooth structure.

This was exactly what we tried to accomplish in the presented case of a young man who was unhappy with the appearance of his maxillary anterior teeth. The existing veneers on his maxillary central and lateral incisor did not have the desired colour and shape. Hence, the patient expressed the wish to replace the restorations and do what would be needed for a bright, natural and youthful smile.

Fig. 1. Initial clinical situation: Smiling patient.

Fig. 2. Appearance of the maxillary incisors with restorations that do not meet the patient’s aesthetic demands.

TREATMENT OPTIONS AND TREATMENT PLAN

To improve the young patient’s smile aesthetics, a replacement of the existing veneers seemed most appropriate. To provide for a perfect dental and facial harmony, we decided to produce laminate veneers using the refractory die technique for all six maxillary anterior teeth. However, full veneers were only planned for those teeth that had already been prepared for the existing restorations. In the canine region, we opted for an even more conservative approach: Two non-prep feldspathic partial veneers with infinity margins were to be produced.

CLINICAL PROCEDURE

For this purpose, the old restorations were removed and the previously prepared teeth were refined with rotary instruments to develop ideal veneer preparations with smooth surfaces and well-defined finish lines. The margins were located supragingivally instead of subgingivally to increase the simplicity, accuracy and predictability of clinical procedures like impression taking and adhesive cementation. The marginal fit and long-term stability of the restorations are also likely to be improved by placing this measure, which is, on top, less invasive and hence healthier for the patient. The surface of the canines was merely roughened. To get a clear picture of the patient’s aesthetic expectations, the dental practitioner took an impression, which was send to the dental laboratory. Here, we developed a wax-up, which was transferred into the patient’s mouth in the form of a mock-up. This mock-up served as a temporary restoration and allowed us to evaluate the shape, surface texture and shade of the planned restorations in situ. In consultation with the patient, the mock-up was modified slightly, while the information about the approved shape, texture and shade was transferred back into the laboratory via images and a preliminary impression.

Fig. 3. Temporary restoration in the patient’s mouth.

Fig. 4. Situation after tooth preparation with supragingival preparation margins.

TECHNICAL PROCEDURE

Based on the precision impression, a master cast was produced. This cast served as the basis for the production of removable dies and a high-precision alveolar model. Finally, the dies were duplicated using the refractory die material NORI-VEST (Kuraray Noritake Dental Inc.) needed for veneer production with the desired technique. On those dies, the preparation margins were marked with a pencil, while the surface that would come in contact with the porcelain was treated with a plaster separating agent to facilitate removal of the veneers from the model.

Fig. 5. Dyes placed in the impression.

Fig. 6. Stone Super Rock EX type IV for production of the alveolar model.

Fig. 7. High-precision alveolar model with six separate removable dies.

Fig. 8. Model with duplicated refractory dies, marked irregular preparation margins and separator liquid on the surfaces.

Then, the first layer of synthetic feldspathic porcelain (CERABIEN™ ZR Opacious Body White, Kuraray Noritake Dental Inc.) was applied. After the initial bake, a second layer of Opacious Body, which allows a shining through of the original tooth colour, was used to build up the integration structure. Following the second bake and assessment of the available space with the aid of a silicone index, we built up the cervical, body and incisal areas with the respective porcelains (A1B, CCV-1, and Enamel 1), before a final layer of Luster (LTX and ELT3) was applied. Morphological corrections were carried out after the final bake, and the essential anatomical surface details including line angles, cervical portion and incisal grooves were marked with coloured pencils. This served the purpose of integrating the desired natural surface texture into the laminate veneers with rotating instruments (PA and PB rubbers, from SHOFU). When it comes to checking the final surface details, the application of golden (Eyes Texture from MPF) texture powder offers valuable support in order to see the imperfections of surface and to correct it. It clearly reveals all the surface cracks, tiny grooves and other characteristic effects. Final polishing was accomplished with MPF all bright Diamond Paste, followed by self-glazing bake program with CERABIEN™ ZR FC Paste Stains in order to add some effects.

Fig. 9. Second layer of CERABIEN™ ZR Opacious Body applied to create integration and mamelons.

Fig. 10. Evaluation of the available space using a silicone index.

Fig. 11. Building up of the cervical and body areas.

Fig. 12. Surface of the veneers marked with coloured pencils: Vestibular view.

Fig. 13. Surface of the veneers marked with coloured pencils: Occlusal view.

Fig. 14. Evaluation of the created surface details using MPF Eyes texture.

Fig. 15. Palatal view of the veneers with texture powder.

In Figures 16 to 18, the final restorations are shown on the alveolar model. The veneers and partial veneers restore the maxillary anterior teeth to their optimal proportions. While the shade of the restorations is quite bright as desired by the patient, the natural shape and surface texture will make a major contribution to a natural and aesthetic harmony. Looked at separately, the minimal thickness of the veneers and partial veneers is revealed (Fig. 19). The margins are extremely thin, so that even the partial veneers will allow for a smooth optical integration without any visible finish line (infinity margin).

Fig. 16. Finished full and partial veneers on the model.

Fig. 17. Detailed view of the first quadrant.

Fig. 18. Detailed view of the second quadrant.

Fig. 19. Extremely thin veneers and partial veneers.

ADHESIVE CEMENTATION AND FINAL OUTCOME

After successful try-in, the adhesive surfaces of the restorations were treated with a buffered nine percent hydrofluoric acid (Ultradent™ Porcelain Etch) for 90 seconds according to the manufacturer’s instructions. During this step, it is extremely important to observe the recommended protocol, as excessive etching may weaken the ceramic structure. Subsequently, the teeth were cleaned and the veneers then adhesively cemented starting with the two central incisors and proceeding one by one. The selected light-curing adhesive cementation system (Variolink Esthetic LC) includes a universal restoration primer, phosphoric acid and a universal adhesive for the tooth structure. For restorations with limited light penetration, the use of dual-cure resin cement might be beneficial. The treatment outcome is shown in Figures 20 to 24.

Fig. 20. Portrait picture of the patient after treatment.

Fig. 21. Close-up of the patient’s smile.

Fig. 22. Lateral view of the new smile from the right.

Fig. 23. Lateral view of the new smile from the left.

Fig. 24. Overall optical integration of the veneers in the anterior region of the maxilla.

Fig. 25. Close-up of the final treatment outcome confirming a smooth transition from restorations to tooth structure and harmonic pink and white aesthetics.

CONCLUSION

The described conservative treatment approach can be challenging as the produced full and partial veneers are extremely thin. Especially during try-in and adhesive cementation, care must be taken not to break them.

At the same time, however, the full and partial veneers are a great option particularly for young patients asking for cosmetic dental treatment. They allow for minimally to non-invasive tooth preparation, while it is possible to play with the proportions and shade of the teeth. Even the colour of the underlying dentin can be nicely revealed for a more vivid appearance, and a smooth transition from natural tooth structure to restoration can be achieved even if the finish line is in no way hidden by the gums. In the present case, the restorative team succeeded in restoring the young patient’s smile in a bright and natural way – giving him exactly the smile he desired.