1985 Volume 4 Issue 1 Pages 62-67,122
The color and optical properties of three anterior and four posterior composites were determined from reflection spectrophotometric data and Kubelka's equations. Samples were aged for 300 hours at 43°C, 90% relative humidity, intermittent water spray, and continuous exposure to a 2500 watt xenon light. After aging the composites were generally darker, more chromatic, and more opaque. Values of S (absorption coefficient) and K (scattering coefficient) increased and values of XI (infinite optical thickness) decreased. The light-cured composites were less stable than the chemically cured ones.