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CAD/CAM - international magazine of digital dentistry

24 I I case report _ full-arch restoration temporary bridge should be rigid (framework) and easily removable (screw fixation). Site #27 healed un- eventfully,protectedasitwasfrommechanicalstress. _Final bridge At the end of the six-month healing period, prepa- rationforthefinalrestorationbegan.Wearingthetem- porary bridge had allowed adjustment of the above- mentioned parameters (e.g. aesthetics, phonetics and lip support) and validation of the vertical dimension andintermaxillaryrelationship. The temporary bridge was removed, an implant stability percussion test was performed, and control radiographs were taken. The straight conical abut- ments that had been placed concomitant with the implants were tightened to 25 Ncm (as recommended by the manufacturer), except abutment #23, which wasangled(Fig.8). Animpressionofthefinalbridgewastakenwiththe same impression tray used for the temporary bridge. Pick-up transfer copings were interconnected using LuxaBite resin (DMG), and the impression was made usingImpregum(3MESPE).Themastermodel,includ- ing the conical abutment analogues and silicone soft tissue (representing the patient’s gingiva), was fabri- cated and then validated in the dentist’s office via a wax bite block (into which extra-hard plaster mate- rial was poured). The wax bite block was then tried in (Figs.9a–d). Using silicone indices (vestibular, occlusal and palatal)fromthetemporarybridge,awax-upwasfab- ricated in the laboratory (Fig. 10). The wax-up had to meet the aesthetic demands of the patient and be an exact replica of the temporary bridge (both anatomi- cally and aesthetically). The validated master model and wax-up were sent to the SIMEDA machining cen- tre, where the master model was scanned and a CAD modelwasdesigned(Figs.11a–d).APDF3-Dfileisused to validate the design, after which the manufacturing process can be initiated. All pieces are machined from titanium blocks using high-precision five-axis milling machines(Figs.12a–c). Titanium is a lightweight material and, more importantly, it is highly biocompatible and has superior mechanical properties. It is four times lighter than commonly used semi- preciousalloys.Actually,itisthelightestmetal used in dentistry. Furthermore, titanium is a self-passivating metal: it readily reacts with oxygen in air to form a tough layer of oxide, which protects against corrosion. Titanium is known to resist corrosion and chemical at- tacks extremely well. Furthermore, it is bac- tericidal, a key advantage for dental implants. Figs. 13a & b_The machined titanium framework. Figs. 13c–f_The final bridge. Fig. 13g_The patient’s new smile. Fig. 13h_A post-op panoramic radiograph with the bridge in place. CAD/CAM 3_2014 Fig. 13e Fig. 13fFig. 13d Fig. 13b Fig. 13cFig. 13a Fig. 13g Fig. 13h CAD0314_20-25_Marcelat 25.08.14 12:27 Seite 5

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