evaluation of the surface roughness of a standard abraded dental porcelain following different polishing techniques

Background/purpose: To evaluate the surface roughness of the metal ceramic VITA VMK 95, a standard dental porcelain used for metal-ceramic restorations. Materials and methods: Glazed ceramic blocks of VITA VMK 95 were grinded using a rugby-shaped diamond bur in order to mimic the chairside-adjustment process and then polished using two polishing techniques. Polishing was performed using Sof-Lex discs or Sof-Lex discs followed by polishing with brushes and a prophylaxis paste. To evaluate the surface roughness, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) using the Genie digital image capture system were performed. Average roughness (Ra), root mean square roughness (Rq), valley roughness (Rv), and peak roughness (Rp) were evaluated using CLSM. Results: The results were analyzed using one-way analysis of variance with the post hoc Tukey test at a significance level of 5%. There were statistically significant differences between the rough group and the two polished groups (P<0.05). There was no statistically significant difference between the two polished groups (P>0.05). Conclusions: Although the Sof-Lex discs significantly reduced the surface roughness, their use with the prophylaxis paste and polishing brushes did not cause a further reduction in the surface roughness.