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10 CASE STUDY tion should be made of the same material because this guarantees maximum stability. If possible, we now always try to carry out Platform Switching. This is defined as the diameter of the abutment being less than the diameter of the implant. The resulting shift of the gap in the implant-abutment connection from outside to inside on the implant shoulder is intended to have a positive effect on the establishment of the biologic width and to stabilize the soft tissue on the shoulder. However, this only works with adequate soft tissue thickness [24]. Because CAMLOG does not currently offer any titanium adhesive bases with which such Platform Switching could be done, we use standard abutments that can achieve this. The dental technician must then grind these abutments back so that the connection geometry is not violated and the material remains suffi- ciently stable (Fig. 26) . The subsequently visible, individual part of the abutment is then built up on this customized part. The wax superstructures are then scanned and milled in zirconia with the future cement gap to be located epigingivally (Fig. 27 and 28) . After sintering we cement the polished titanium abutment to the zirconia superstructure (Fig. 29) . The customiza- tion with zirconia means that we have created an abutment that comes very close to a natural tooth in the emergence profile (Fig. 30) . It should be noted that the angle with which the zirconia penetrates the soft tissue is not less than 45 degrees because otherwise the gingiva is not displaced but instead compressed, which is likely to cause it to regress. The part of the zirconia that will be located beneath the mucosa must be polished to a high shine so that plaque cannot adhere to the surface. As a result of the high biocompatibility of the zirconia in the emergence profile, a hemi- desmosomal attachment of the gingiva can take place, which in the optimal case prevents migration of bacteria apically. Nowadays we prefer to use crowns made of lithiumdisilicate for posterior teeth in almost all cases because these are prepared as monolithic restorations and can be adhesively retained. The crowns are waxed up and pressed in-house because the stability of pressable ceramic is higher than milled ceramic. After preparation and customization, the results are perfectly fitting and highly est- hetic crowns (Fig. 31 and 32) . The healing caps are removed to cement the finished restoration. A stable peri- implant cuff of soft tissue is apparent (Fig. 33) . The implants are rinsed with CHX and filled with 1% CHX gel. Then the hybrid abutments are screwed onto the implants with a defined torque of 20 Ncm. We use an insertion key that helps us to also check whether the impression was carried out precisely (Fig. 34) . After five minutes the abutment screws are retightened with the defined torque to prevent subsequent loo- sening of the screws. The screw channels are filled with foam pellets and sealed with a light-cured composite. A foam pellet has a number of advantages: it is quickly inser- ted, it protects the screw head from any composite that penetrates the channel, and it does not develop any wicking effect as cotton swabs do, for example (Fig. 35) . Full-ceramic crowns should always be used with adhesive because studies have shown that fractures often occur after conventio- nal cementing [27]. In the lateral view the location of the subsequent cement junc- tion can be seen on the abutments (Fig. 36) . We prefer to position these in non-vi- sible areas epi- or supragingivally to ensure Fig. 25: The impression was taken with an individual tray using the open tray impression technique. Fig. 26: Individualized titanium abutments served as adhesive bases for the hybrid abutments because the reconstruction should be done on Platform-Switching abutments. Fig. 32: The perfectly fitting IPS e-max Press crowns were stained and polished. Fig. 31: The crowns underwent full-contour wax-up and pressing. Fig. 27: The hybrid abutments were modeled in wax for CAD/CAM fabrication. The later cement gap was located epigingivally. Fig. 33: After removing the healing caps, stable soft-tissue cuffs around the implant could be seen.