Effect of polishing technique on the surface topography and transmittance of the composite resin

Introduction:Clinically, it is common to observe the effects of composite restorations stratification only after the polishing.Aim:This study evaluated the effect of polishing technique on light transmittance and surface topography of a composite resin.Material and method:Specimens of the composite resin Filtek Z-350 XT (color A1E) were built-up using a metal matrix. One of the specimens surfaces was finished with 12-blade burs and polished using one of following techniques: SL (Sof-Lex), EH (Enhance) and DH (DHPro). No polishing was used as control. After the polishing procedures, the samples were measured to check the final thickness (1 mm). The light transmittance was measured using a spectrophotometer connected to an integrating sphere, considered only light in the visible spectrum. The surface topography was measured by laser interferometer, assessing the parameters Sdq (hybrid), St (maximum amplitude) and Sa (average of peaks and valleys). Data (n=5) were submitted to ANOVA and SNK's test, while Pearson's correlation test was used to related Ssq, St and Sa to transmittance (α=0.05).Result:All polishing systems increased the light transmittance when compared to control, whereas no difference was observed between them. Only the samples polished with SL and DH showed lower Sdq values than control. Although for St and Sa parameters, EH showed lower values than those observed for control. Sdq and St showed significant correlation with transmittance.Conclusion:All polishing systems were effective to increase the transmittance, while the reduction of Sdq and St values were related to this modification.