Optical properties of composites of selected shades in white light.

Light reflectivity, scattering coefficient, absorption coefficient, infinite optical thickness, and contrast ratio were determined in white light, for seven shades of a conventional composite and five shades of a microfilled composite, from reflection spectrophotometric data using Kubelka's equations. Significant differences among shades were observed for each property. Values of infinite optical thickness ranged from 2.97 to 5.90 mm among the shades studied.