Can Polishing Systems Restore the Smoothness of Glazed Ceramics?

Aim: The purpose of this study was to analyze the surface roughness of three mechanically polished feldspathic ceramics by using two different polishing systems after simulated occlusal adjustment.

Methodology: Thirty feldspathic ceramic discs were fabricated: 10 with Duceram, 10 with Duceragold, and 10 with Symbio Ceram. All specimens were glazed, and 8 specimens in each group received simulated occlusal adjustment with diamond burs. Half of the 8 specimens was polished using the Edenta system, and the other half was polished using the Komet system. The mean surface roughness was measured before and after surface polishing using the Rugosimeter SL-201. Qualitative analysis of the ceramic surfaces was performed by scanning electron microscopy (SEM) in two glazed specimens and in two polished specimens. The data were submitted to analysis of variance for repeated measures, followed by Tukey's test (α=0.05).

Results: The Edenta system produced statistically lower surface roughness than the Komet system for the Duceram and Duceragold ceramics (p<0.05). However, for the Symbio Ceram ceramic, there was no significant difference between the Edenta and Komet systems (p>0.05). The application of diamond paste significantly decreased the roughness of the ceramic surface compared with the isolated application of the Komet or Edenta system. The SEM images showed that the mechanical polishing did not restore the surface smoothness of the glazed surfaces.

Conclusions: Neither the Edenta nor Komet systems reproduced the surface smoothness of glazed ceramics. The use of diamond paste considerably reduced the surface roughness. The Edenta system provided lower surface roughness than the Komet system.