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ePaper created 2017-01-24, 10:47:27 | version 1.38.0
18 I I clinical_ implant restoration The printed model is scanned using the Planscan (Fig. 7). To ensure the abutment color is properly blocked out, an emax LT block (Ivoclar/Vivadent) should be used to fabricate the final restoration. emax has the strength to be conventionally ce- mented provided the occlusal thickness is 2 mm or more. Because the milled custom is shaped essentially like a natural tooth, preparation fabrication of the final restoration is completed in much the same fashion as any natural tooth. The only exception is margin ramp and axial spacer settings. As the abut- ment generally has ideal taper and contours, I will set the margin ramp at .5 and the axial spacer at .05 (Fig. 8). Also for implant crowns, it is important to mill in detail mode to get the most precise fit to the abut- ment as possible. The abutment has ideal taper and is perfectly smooth, which allows the mill to create a very intimate fit when the conical bur is used to mill the internal aspect of the crown. Also always perform a mill simulation in detailed mode to ensure there is no internal binding of the restoration. Theeasiestwaytocheckforinterferenceistosim- ply flip the simulation screen over and check to see if any blue bleeds through in the axial areas (Fig. 9). If any blue bleeds through the tan model, go back to the design screen and open the axial setting by .01 and simulate again. Keep nudging the spacer out until you get the tightest fit without interference. Anexcellent-fittingcrownisproducedbythemill with extremely accurate margins (Fig. 10). Proximal and occlusal contacts are evaluated on the printed model/analog and adjusted as needed while the emax is in the purple phase. The restoration is stained and glazed in the same manner as a tooth-retained crown (Fig. 11). One of the big advantages of using emax for an implant restoration vs a layered restoration is the reduction in fracture potential. Traditional layered ceramics are more prone to chipping in implant ap- CAD/CAM 3_2016 Fig. 7_ Printed model and analog scanned using the Planscan. Fig. 8_ Crown is designed. Fig. 9_ Flipped Mill Sim model. Note the lack of axial interference. Fig. 10_ Precision fit of the milled emax to the titanium abutment. ‘The open source nature of the Planmeca FIT system allows users the flexibility to utilize their systems in a variety of workflows to provide care for our patients.’ Fig. 7 Fig. 9 Fig. 8 Fig. 10