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ePaper created 2018-01-31, 10:01:59 | version 1.38.0
| case report Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 10: The CAD data of the digital impressions of the prepared teeth and the mock-up are superimposed. Fig. 11: Veneers ready for placement. Fig. 12: Restorations on the model after CAD/CAM-supported fabrication of the ceramic veneers. Fig. 13: Adhesive cementation of the ceramic veneers with a rubber dam in place. Transfer to the mock-up We created a silicone key of the vestibular surfaces with the help of the wax-up and applied a thin layer of composite material into the key using a spatula (IPS Em- press Direct; Fig. 3). Once light-cured (Bluephase with Polywave LED), the resulting composite veneers for teeth 15 to 25 were placed on the model and stabilised with wax (Figs. 4a & b). Once the wax-up was finalised, it was duplicated and cast in stone. We created a silicone key from this model to assist the dentist in the preparation of the teeth. The silicone key was created in two steps using two different silicone materials, one with a high hardness (Silico Dur, Cendres+Métaux) and the other with a low hardness (3M ESPE Express). The silicone key served to create the mock-up and the temporaries. Tooth preparation and data transfer to the lab The mock-up was inserted with the help of the sili- cone key and the surface texture was reworked using a polishing system (Astropol; Fig. 5). The aesthetic effect was validated with photographs and videos. The patient could also inspect the pictures (Figs. 6 & 7). Then, the teeth were prepared using a ball-shaped bur whilst the mock-up was in place (Galip Gürel 2003) (Fig. 8). This procedure meets the requirements of minimally invasive dentistry. An impression of the prepared teeth (Fig. 9) was taken using an intraoral scanner and the temporaries were fabricated with the help of the silicone key. At this point, the dentist is required to take two optical impressions: first, an impression of the prepared teeth and, second, an impression of the temporaries in the mouth. In addition, a conventional silicone impression of the prepared teeth is taken. The dental technician will use this impression to produce a physical model to check the fit and contact points of the milled ceramic veneers. Creating the final restoration For the CAD construction, the two data sets (temporar- ies, prepared teeth) were superimposed in the software (Fig. 10). Subsequently, the shape of the temporaries was matched to the preparation margins. Each component was examined (preparation margin, thickness, contact points, etc.) separately before the data was transmitted to the milling unit for machining (Fig. 11). For the fabrication of the veneers, we decided to use the IPS Empress CAD Multi blocks, which feature a lifelike shade transition from the dentine to the incisal. We selected a block in shade A1. Each veneer was positioned in the block in such a way that the translucency of the incisal area matched our requirement. Once the veneers were milled, we checked their fit on the prepared dies of the model and assessed their contact points with each other. The surface texture was lightly reworked (Fig. 12). To achieve a highly aes- thetic result, we additionally characterised the veneers with Stains and Essence materials (IPS Ivocolor) before we glaze-fired them (Fig. 11). 24 CAD/CAM 1 2018