EFFECTS OF FINISHING AND POLISHING PROCEDURES ON THE SURFACE TEXTURE OF RESIN COMPOSITES

Objectives, This study was designed to investigate the effects of fini shing and polishing procedures on the roughness and color of resin com posite surfaces.Methods. Four composites and three different polishing systems were evaluated. Forty disc (10 mm x 2 mm) specimens of each c omposite were prepared. Thirty of them were ground wet through 320-gri t paper, and the ground surfaces were used as the base line for the fi nishing procedure. Ten Mylar-covered specimens were used as controls. A color meter was applied to determine the color differences and a rou ghness meter was used to measure the surface roughness (Ra). Results. Microfilled composite demonstrated significantly less roughness (p les s than or equal to 0.01) than hybrid composite systems as tested by AN OVA and Scheffe's tests. Polishing procedures produced a decrease in t he roughness, ranging from 26 to 74%. Relative to the shade guide, the mean color difference values for all the composites after polishing w ere significantly greater than for the controls (p less than or equal to 0.01) and ranged from 1.08 to 8.15 units. A positive relationship b etween mean color differences and Ra values was determined by regressi on analysis (r = 0.55). Significance, A Mylar strip can create a smoot her surface than the other types of tested polishing procedures. Becau se of the greater values in color differences and surface roughness, t he shades of tested resin composites were lighter after the polishing procedures. A custom-made shade guide is suggested based on the result s of this study.