Depth of Cure in the UV Photopolymerization of Dimethacrylate-Based Dental Filling Materials

Abstract

The photopolymerization of dimethacrylate-based resins, employed as dental filling materials, is often limited in practice to a depth of 1 or 2 mm. Microhardness studies of these materials indicate that the degree of cure below the surface is relatively constant until a depth is reached at which the extent of polymerization rapidly decreases. Based on the kinetics of photopolymerization, two simple models were derived which appear to be qualitatively consistent with this behavior. One of these models was also in general agreement with the dependence of the depth of cure on the exposure time, radiation intensity, absorption coefficient of the material, and the inhibitor concentration in the resin.