Francesco Ferretti

Case by Francesco Ferretti, MDT

Is it possible to produce lifelike porcelain veneers using lithium disilicate and a porcelain system with a reduced number of internal stains and porcelains designed for micro-layering? This is what we wanted to find out when we decided to test the new CERABIEN™ MiLai line-up. As loyal users of the CERABIEN ZR family for porcelain layering on zirconia, we hoped that the new product would offer similar handling and optical properties.

The CERABIEN™ MiLai line-up consists of 15 internal stains and 16 porcelains, which are - like CERABIEN ZR - based on synthetic feldspathic porcelain technology from Kuraray Noritake Dental Inc. With a comparatively low firing temperature of 740 °C (or 1,364 °F), the system may be used on zirconia as well as silicate ceramic restorations, provided that the CTE value of the materials is between 10.2 and 10.5 × 10^-6/K (50 °C – 500 °C). This is true for lithium disilicate, our preferred base material for the production of ceramic veneers. The thickness of the porcelain layer is usually smaller than 0.5 mm, which allows us to exploit the aesthetic potential of the underlaying ceramic, while creating some individual effects for the underlying structure and the enamel. A clinical case predestined for the use of the new system is shown below.

Fig. 1. Young male patient with discoloured composite restorations on his maxillary central incisors.

Fig. 2. The patient was unhappy with his smile aesthetics, so that it was decided to place more durable ceramic veneers.

Fig. 3. Appearance of the central incisors after minimally invasive tooth preparation.

Fig. 4. Veneers made of lithium disilicate individualized with CERABIEN™ MiLai placed on the model.

Fig. 5. Intraoral view of the teeth after adhesive cementation of the veneers.

Fig. 6. Close-up view of the anterior teeth.

Fig. 7. Smooth optical integration of the veneers: They show some individual effects and are virtually indistinguishable from natural tooth structure of the adjacent lateral incisors.

Fig. 8. Black-and-white photograph of the maxillary anterior teeth.

Fig. 9. Smile aesthetics.

Fig. 10. Beautiful treatment outcome.

COMPACT SYSTEM

The compact line-up of CERABIEN™ MiLai with its nicely developed internal stains and porcelains enables us to imitate the patient’s natural teeth very well in the great majority of cases. Shades are easily selected and the favourable consistency of the porcelains facilitates application in thin layers. Due to the reduced thickness of the porcelain layer, it is possible to play with the optical properties of the underlying lithium disilicate, creating a final restoration with a natural appearance despite the simplified procedure.

Case by Francesco Ferretti and Marco Nicastro

Aesthetic restoration of anterior teeth using KATANA™ UTML Full anatomical crowns, with vestibular stratification and BOPT*¹.

^{*1 Biologically Oriented Preparation Technique}

Initial situation

Final result

Shows excellent aesthetic properties of KATANA™ UTML and the perfect integration in harmony with pink tissues.

Figure 1. The patient requested a solution for an aesthetic problem due to unnatural look of old restorations and black triangles coming from past history of periodontitis. The resulting retraction of the tissues had left the margins of the prosthesis clearly visible, and the loss of the papilla peaks, together with the numerous black spaces between the crowns, required a complex therapeutic approach.

Figure 2. The treatment plan for the periodontal problems con-sisted of a non-surgical approach, with scaling and root planing, and the replacement of the previously fixed prostheses to recondition the marginal tissues and facilitate the restoration of a new, aesthetically pleasing gingival architecture.

Figure 3. From a functional point of view, we decided to reduce the deep frontal bite to restore a correct overjet-overbite ratio. This reduction was also important from an aesthetic point of view, as it allowed us to shape the various elements correctly.

Figure 4. We usually remove old prostheses before beginning a periodontal treatment, and make a first, provisional restoration to create an environment in which the soft tissues can heal. If we have to work beyond the cement enamel joint (CEJ), we prefer a vertical preparation for posts, and the purpose of the provisional restoration is to condition the marginal tissues using Dr. Loi’s BOPT.

Figure 5. For the BOPT, the vertical preparation of the post has a finish line that extends inside the gingival sulcus. The temporary conditioning of the tissues induced by the provisional prosthesis allows us to modify the level of the gingival parables to a certain extent.

Figure 6. The image on the left shows the clinical healing of the tissues one month after the initial periodontal treatment. The role of the provisional restoration, appropriately realigned, is clear. The conditioning of the tissue has been achieved by means of the provisional restoration, which has modified the level and shape of the marginal tissue. Once filled with correctly fitted crowns, the interproximal spaces will be further reduced after the definitive restoration.

Figure 7. The correct management of the provisional restoration is crucial for the healing of the tissues. The placement of a provisional restoration before the periodontal therapy has allowed us to create the right environment for complete healing. At the same time, the vertical preparation has allowed us to gradually condition the marginal gingival tissue by shortening or lengthening the provisional restoration as necessary.

Figure 8. One of the advantages of a vertical preparation is that taking the final impression is easy, because the absence of a horizontal finish line greatly simplifies the procedure. On the other hand, the BOPT also requires the taking of an impression of the sub-gingival portion of the preparation. The dental technician will have to decide marginal shape of restorations according to the position of the gingival line in consultation of the clinician, and based on the tests conducted with the provisional restoration.

Figure 9. After the casting of the model, we prepared the gingival area to accommodate an ideal configuration of gingival parables.

Figure 10. After making a wax model, we assessed whether the height of the gingival zenith level could be further corrected. This photo shows that gingival level of 21 was not yet ideal, so we stretched it distally.

Figure 11. Once the wax model was complete, we extracted the element from the model and evaluated its protrusion. It was only after joining the gingival protrusion to the arbitrary margin of the preparation that we proceeded to a scan and milled the crowns.

Figure 12. The restoration was carried out with Katana™ UTML zirconia based on the new formulation of cubic zirconium oxide. This ultra tralucent material was chosen because we were working with light and non-discolored posts.

Figure 13. We finished the crowns on a positional impression to help to improve the gingival adaptation; we had some dispersion of the tissues in the first precision impression due to the use of retractors. We finished the crowns with CZR FC Paste Stain colours and glaze.

Figure 14. The surface colours and the slight contrast created are highlighted in this black-and-white image taken with a blue filter.

Figure 15. In this translucent image, we can see the natural translucent effect of KATANA™ UTML and invisible fusion between abutments and crowns.

Figure 16. Clinical image one year after cementation made with PANAVIA V5; this shows the good clinical condition of the marginal tissue, with no signs of inflammation or bleeding. The BOPT allowed us to optimise the level of the gingiva without resorting to periodontal surgery, while the shape of the new crowns has made it possible to close all interproximal spaces for an optimally aesthetic result.

Figure 17. The brightness of the restorations (thanks to the use of a particularly translucent zirconia) combined with the shape of the incisors, has greatly im-proved the aesthetic of the restoration, even though the condition initially appeared to be particularly unfavourable.

Figure 18. Compared to the previous prostheses, the incisal reduction allowed not only for the optimisation of the functional phase by reducing the overbite, but also made it possible to achieve a more natural aesthetic, with the contour of the incisal margins following that of the lower lip.