Effects of specular component and polishing on color of resin composites

This study evaluated the effects of the specular component mode of specular component included (SCI) and specular component excluded (SCE), and the grit size of final polishing with SiC paper on color of different types of resin composites and shades. Resin disks of 2 mm in thickness were made with regular, opaque and enamel shades for each of the following: supra-nano spherical filled Estelite Σ Quick (EQ), organic filled hybrid Clearfil Majesty (CM), and S-PRG filled nano-hybrid Beautifil II (B2). One week after curing, the surface roughness and color were measured. Color differences between 3000- and 1000-grit, and between 3000- and 180-grit final polishing groups were calculated. Comparison of L*a*b* between SCI and SCE modes showed that the L* values with SCI were significantly higher than those with SCE in 1000- and 3000-grit groups for EQ and CM, and in 3000-grit group for B2. Comparison of total color differences (ΔE*ab) between SCI and SCE modes for all resin composites and shades in all polishing groups showed that the ΔE*ab with SCE were higher than those with SCI except for opaque shade of EQ with white background in 1000-grit group in which the ΔE*ab values were same. The effect of the specular component mode and polishing on color differed among the resin composites and shades.