Surface roughness of a novel "ceramic restorative cement" after treatment with different polishing techniques in vitro

The aim of this study was to determine the surface roughness of a novel calcium aluminate cement (CAC) intended for posterior restorations after treatment with different polishing devices in vitro. Forty-eight CAC specimens were polished with diamond burs at 15550 rpm or 27000 rpm, Sof-Lex discs, Jiffy points, Shofu silicone points, and Aaba universal polisher. Amalgam specimens were polished with Shofu silicone points and used as reference. Roughness was measured using a profilometer. The smoothest CAC surface was observed after use of the fine Sof-Lex disc (roughness average [Ra] 0.26 microm). Diamond burs at higher speed, points, and polisher gave rather similar results (Ra 0.58-0.72 microm). An increase in surface roughness could be seen from using diamond burs at lower speed (Ra 2.3 microm). Extra fine Shofu points and Sof-Lex discs as a final step reincreased surface roughness. Polished amalgam showed the smoothest surface in the study (Ra 0.17). It can be concluded that the smoothest CAC surfaces were obtained with the fine Sof-Lex discs. Different polishing points and diamond burs at higher speed, which are suitable polishing devices for posterior restorations, also gave relatively smooth surfaces.