Abstract
Use of light-activated composite resins have advantages over chemically activated composite resins, such as no need to mix pastes and more working time. However, the light-activated composites have a disadvantage in that they do not cure effectively at the base of the deep restoration, because a minimum intensity of light must reach it for an effective cure.
This study examined the effects of the refractive indices of base resins and fillers in the light-activated composites on the depth of cure. Several kinds of dimethacrylates were used as base resin monomers and colloidal silica was used as a filler. As a result, the monomer which has a similar refractive index to that of silica transmitted light effectively and cured deeply. The polymer had a larger refractive index than that of the monomer and the cured resin containing a filler hardly transmitted light.
It is inferred that the monomer which has a refractive index similar to that of the filler and does not change during polymerization will enhance the depth of cure of light-activated composite resins.
