Optical properties of esthetic restorative materials and natural dentition.

The diffuse reflectance spectra of dental ceramic and composite resin specimens were analyzed by the Kubelka-Munk (K-M) theory of light scattering materials. This enabled the prediction of the spectra and color of differing thicknesses of these materials on various backgrounds, which were in good agreement with observation. The reflectance spectra of natural enamel and dentine sections were also measured on white and black backgrounds. This allowed the calculation of the K-M scattering (S) and absorption (K) parameters, which were compared with those of the restorative materials. The Chroma of these tooth sections increased slightly with the age of the patient, but the Hue and Value showed no systematic variation. Comparisons of the measured Munsell color for a range of composite resins and ceramics with that of the natural tooth sections showed that they generally exhibited a similar range of colors.