Effect of different finishing and polishing techniques on the surface roughness of four ceramic materials after surface adjustment

Purpose: To measure and compare the surface roughness of glazed and polished monolithic ceramic materials with the surface roughness produced by different intraoral polishing systems on adjusted monolithic ceramic materials. Materials and Methods: Milled ceramic disks (10mm diameter x 2mm thickness) were manufactured and distributed according to the following groups (n=10): BruxZir (glazed and polished), Zenostar (glazed and polished), IPS Empress and IPS e.max. Surface roughness, expressed as Ra and RMS values, was measured using AFM and profilometer before and after adjustment and polishing with the following intraoral polishing systems: BruxZir and Dialite ZR (for BruxZir), Zenostar and Dialite ZR (for Zenostar), and OptraFine and Dialite LD for IPS Empress and IPS e.max Mean and standard error for each material and polishing system were calculated. Data were analyzed with T-test, one-way ANOVA, and Bonferroni post hoc tests. Results: In general, all materials presented a smoother surface at baseline than after adjustment and polishing. The AFM results showed that baseline values were not significantly different among the groups. Significantly lower Ra and RMS values (p<0.05) were obtained when BruxZir Polished was polished with Dialite ZR when compared to BruxZir System and IPS e.max specimens were adjusted and polished with OptraFine System in comparison to Dialite LD System. Statistically significant difference was found in Zenostar Glazed and IPS Empress groups (p<0.005) and lower Ra and RMS values were found using the Zenostar polishing system in Zenostar glazed respectively.;The profilometer results showed that the Ra and RMS baseline values of BruxZir polished and Zenostar polished were significantly lower than all other materials. After adjustment and polishing, BruxZir polished and BruxZir glazed specimens presented significant difference (p<0,005) and lower RA and RMS values when Dialite Zr was used compared to BruxZir. Conclusions: BruxZir zirconia resulted in a smoother surface with Dialite ZR polishing system compared to BruxZir polishing system, Zenostar zirconia produced a smoother surface with Zenostar polishing system compared to Dialite ZR polishing system and IPS Empress CAD and IPS e.max CAD presented a smoother surface with OptraFine polishing system in comparison to Dialite LD polishing system. The AFM complements the Profilometer information and should be recommended in surface roughness studies in dental ceramics.