SURFACE EVALUATION OF ZIRCONIA MILLED BY CAD/CAM TECHNOLOGY
zirconia; surface roughness; CAD/CAM technology; diamond burs.
Objective: to evaluate the influence of diamond burs wear used to mill zirconia structures by the CAD/CAM system on the zirconia surface. Methods: 201 specimens were milled, using pre-sintered zirconia blocks, with dimensions of 8mm in diameter x 1,5mm in height by means of CAD/CAM technology (Amann Girrbach, Koblach-Austria). The sample milling process was performed using a set of three diamond burs, which were used until the end of useful life of 1.0 diamond bur, controlled by CAD/CAM system. After the milling process, the sintering process was carried out, followed by the polishing process, using mounted stones. The diamond burs were evaluated in scanning electron microscopy (SEM) before and after the milling process. Samples were also evaluated in SEM after the milling process. In addition, the surface roughness of the samples was evaluated using a non-contact optical profilometer to assess their topographic characteristics. Results: the SEM analysis of the diamond burs showed that at the end of the milling process, the diamonds of active zone were reduced. The SEM and optical profilometry sample evaluation showed that there was no significant change in the surface roughness of the zirconia.