Influence of color parameters of resin composites on their translucency

Objectives To determine the influence of color parameters and the difference in color parameters by the background on the translucency of resin composites. Methods Eight light-curing resin composites, a total of 41 shades, were investigated. The color of specimens was measured after polymerization on a reflection spectrophotometer with the SCE geometry over white and black backgrounds. The translucency parameter (TP), contrast ratio (CR) and the difference in color parameters by the background (ΔL*, Δa*, Δb* and image: values over the white background minus value over the black background) were calculated. Correlations between TP values, CR values at every 50-nm interval and the color parameters as well as the differences in color parameters by the background were analyzed with regression analysis. Results Correlations between TP values, and the color parameters and the differences in color parameters were significant except chroma difference (p < 0.01). The correlation between TP values and chroma was significant (r = −0.489 and −0.603, p < 0.01). The correlation between TP values and ΔL* was very high (r = 0.868). Correlations between the color parameters, the differences in color parameters and CR values were varied by the wavelength. TP values were highly correlated with the CR value at the wavelength of 700 nm. Significance More chromatic shades of commercial resin composites were less translucent. Translucency increased as the wavelength increases.