Effect of Polishing on Surface Roughness of Nanofilled Resin Composite

Objectives: To evaluate the effect of different polishing instruments on surface roughness of nanofilled resin composite. Materials and methods: Resin composite, Filtek Z350^®, was condensed in an 5×4×2 mm³ block covered with a Mylar strip and then was polymerized with a curing unit for 40 seconds. 120 specimens were randomly devided into 6 groups equally. The first group was a control. The others were polished with Sof-Lex^® (3M), Enhance^® (Dentsply), Pogo^® (Dentsply), Composhape^® (Intensiv) and Jet bur^® (Kerr). The average surface roughness (Ra) were measured with a profilometer after polishing for 40 seconds, following manufacturer's instruction. Surface topography was assessed using a scanning electron microscope(SEM) from sample of each group. Data were analyzed by one-way ANOVA, at p<0.05 Results: The smoothest surfaces were produced with Sof-Lex^® (0.0164±0.008 μm) which were not statistically different from the control group (0.0156±0.0092 μm). However, polished with Pogo^® (0.0641±0.0601 μm), Enhance^® (0.1801±0.0839 μm), Composhape^® (0.1839±0.0732 μm)and Jet bur^® (0.2626±0.1112 μm) showed a statistically higher average surface roughness than the control group, respectively (p<0.05). Among the experimental group, they all showed statistical differences except between Enhance ^® and Composhape^®. Conclusions: Nanofilled resin composites displayed variable roughness depending on the polishing instruments used; Sof-Lex^® gave the best polished surface.