Abstract
Light-activated composite resins were experimentally prepared from a silica filler and several kinds of dimethacrylates as base resins to study the relationship between their refractive indices and the depth and degree of cure of the resin.The monomer that had a similar refractive index to that of silica transmitted light effectively and was well cured by visible light and ultraviolet ray.Since the refractive index of the base resin became larger with polymerization, the transmittance of the cured resin containing a filler decreased markedly.All the resin monomer/silica filler pastes and those cured products transmitted more visible light than ultraviolet ray.The degree of cure was tentatively evaluated by the rate of the decrease of Knoop hardness inward from the surface irradiated with light, and was related to both the refractive indices of monomers and those of polymers.Thus, as for the refractive index of the base resin monomer for light-activated composite resin, it is desirable to use the monomers with refractive indices which are close to that of a filler and change little during polymerization.
