The aim of this study was to evaluate the effect of two polishing methods and chemical conditioning on the surface of hybrid composites.

Ninety cylindrical specimens (diameter: 8 mm, depth: 2 mm) were made with three hybrid composites - Filtek Z250, Tetric Ceram, DenFil. Specimens for each composite were randomly divided into three treatment subgroups - ① Mylar strip (no treatment), ② Sof-Lex XT system, ③ PoGo system. Average surface roughness(Ra) was taken using a surface profilometer at the time of setting and after immersion into 0.02N lactic acid for 1 week and 1 month. Representative specimens were examined by scanning electron microscopy. The data were analyzed using ANOVA and Scheffe's tests at 0.05% significance level.

The results were as follows:

Mylar strip resulted in smoother surface than PoGo and Sof-Lex system(p<0.001). Sof-Lex system gave the worst results.

The PoGo system gave a superior polish than Sof-Lex system for the three composites. However, the correlation to clinical practice may be limited, since there are several processes, such as abrasive, fatigue, and corrosive mechanisms. Thus, further studies are needed for polishing technique under in vivo conditions.