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ePaper created 2017-03-17, 11:21:45 | version 1.38.0
aesthetic rehabilitation case report | Fig. 7 Fig. 8 Fig. 9 Tooth 22 had received an endodontic treatment. This fact significantly limited the prosthetic options and had a negative effect on the prognosis of this tooth. The developmental stage of the cervical ver- tebrae assessed by the orthodontist using lateral cephalometric radiographs revealed that only min- imal transversal and horizontal growth was still to be expected for this patient. Due to this fact and the unfavourable prosthetic value of the abutment teeth, the prosthodontic team—in consultation with the patient—decided to place an all-ceramic adhesive bridge with two wings bonded to teeth 12 and 22. The aim of this treatment was to postpone the placement of implants as long as possible in or- der to ensure that the patient was fully grown when this intervention was carried out. By use of a fixed restoration, the team strived for the best possible support and preservation of the surrounding soft and hard tissues. First steps After removal of the fixed orthodontic appliances, the direct restorations of the maxillary lateral inci- sors were replaced by new composite restorations. Tooth preparation had already been carried out on these teeth to place the former metal-ceramic bridge. Hence, it was not necessary to remove large amounts of additional tooth structure, how- ever, the existing palatal preparations required refinement. Subsequently, gingiva management was carried out with retraction paste. An impres- sion was taken with the 3M True Definition Scanner and uploaded to the 3M Connection Center. The patient received a removable interim prosthesis (Fig. 5). Laboratory procedure In the dental laboratory, the digital impression file was downloaded, a physical model ordered and the data set imported into the Zfx CAD Software for the design of the adhesive bridge framework. The bridge was designed in full contour. The recommended parameters (minimum wall thickness, connector strength etc.) for the selected material—3M Lava Plus High-Translucency Zirconia—were entered into the software. Then, the bridge was automati- cally reduced to the framework (Fig. 6). This procedure is beneficial in that it provides for a uniform strength and optimal support of the veneering porcelain. The framework was milled, thinned out at the margins using a fine diamond rubber polisher, individualised with dyeing liquids, and sintered. The precise fit of the wings to the palatal tooth surfaces was confirmed on the model before the porcelain layering was performed (Fig. 7). Figure 8 shows the situation at the biscuit-bake try-in. Finally, the adhesive bridge was finished and glazed. On the model, a highly accurate fit was obtained (Fig. 9), and the restoration showed a natural appearance (Fig. 10). This is in part due to the high translucency of the framework material (Fig. 11). Clinical procedure With the use of a GC Fit Checker Advanced Blue (GC Europe), the precise fit observed on the model was confirmed intraorally (Fig. 12). Fig. 7: Precise fit of the sintered framework on the model. Fig. 8: Try-in of the restoration in its fired, unglazed state. Fig. 9: Precise fit of the wings in the palatal area. Fig. 10: Final restoration on the model: A natural colour gradient is obtained. Fig. 11: Light transmission through the translucent framework material. Fig. 12: Use of fit checker to verify the precise fit of the restoration. Fig. 10 Fig. 11 Fig. 12 CAD/CAM 1 2017 13