Effects of finishing and polishing procedures on the surface texture of resin composites

Abstract

Objectives. This study was designed to investigate the effects of finishing and polishing procedures on the roughness and color of resin composite surfaces. Methods. Four composites and three different polishing systems were evaluated. Forty disc (10 mm × 2 mm) specimens of each composite were prepared. Thirty of them were ground wet through 320-grit paper, and the ground surfaces were used as the base line for the finishing procedure. Ten Mylar-covered specimens were used as controls. A color meter was applied to determine the color differences and a roughness meter was used to measure the surface roughness (Ra). Results. Microfilled composite demonstrated significantly less roughness (p ≤ 0.01) than hybrid composite systems as tested by ANOVA and Scheffé's tests. Polishing procedures produced a decrease in the roughness, ranging from 26 to 74%. Relative to the shade guide, the mean color difference values for all the composites after polishing were significantly greater than for the controls (p ≤ 0.01) and ranged from 1.08 to 8.15 units. A positive relationship between mean color differences and Ra values was determined by regression analysis (r = 0.55). Significance. A Mylar strip can create a smoother surface than the other types of tested polishing procedures. Because of the greater values in color differences and surface roughness, the shades of tested resin composites were lighter after the polishing procedures. A custom-made shade guide is suggested based on the results of this study.