EXPERIMENTAL IN VITRO COMPARISON OF THREE DIFFERENT FINISHING AND POLISHING METHODS FOR CERAMICS

Aim. The main purpose of this research is to compare different finishing and polishing methods for dental ceramics, in order to valuate their efficacy to eliminate superficial roughness caused by occlusal touch-ups. Materials and methods. 39 small ceramic disks (Ceramco III) were made in laboratory, to be used as samples during the experiment. All samples were superficially scratched with a mechanic coarse-grained mill (Komet 125 μm), to simulate a chair occlusal touch-up. The disks were randomly divided into three groups. The disks in the first group were finished using Shofu rubber tips, points and polishing disks (One Gloss, Mini-Buff disk, Ceramaster points); the disks in the second group were finished and polished with 3M disks (Sof-Lex); finally, the disks in the third group were finished with Kerr disks and polished with Kerr brushes (Opti disc + Opti Shine ). In all three groups the polishing phase was carried out using both Ultra II diamond paste (Shofu) and installed polishing instruments.The finished samples were analysed with a laboratory profilometer (ZEISS-TSK Surfcom 1400 A n. serie GE1909FL) and some parameters to valuate the superficial roughness were determined. The data thus obtained were then analysed with ANOVA, Duncan and Student tests. Results. The procedure used on the second group proved itself to be the most effective: superficial roughness significantly decreases after finishing, more than in the other groups. The use of diamond paste, together with the three procedures, always improves the superficial situation. In this phase too, the second group had the best results on eliminating roughness. Conclusion. The use of Sof-Lex is proved to be the most effective one. Final polishing, in all three procedures, improves every sample’s surface.