Abstract
To improve the light permeability of the visible light-cured composite resin, the influences of the difference between refractive indices of monomer and filer, and the grain size of filler on the light permeability of light-cured composite resin were investigated by measuring depth of cure. When the refractive index of monomer approached that of filler, the depth of cure of composite resin approached the maximum. The refractive index of matrix resin, however, increased with polymerization of monomer. These results suggested that a monomer with about 0.012〜0.015 lower refractive index than that of filler was most suitable for the monomer component of the light-cured composite resin. When the size of filler was approximately of the same order of magnitude as the wavelength of the visible light, the depth of cure was minimum. This result suggested that the microfiller and the macrofiller were more effective filler component of the light-cured composites resin than the submicron filler. In addition, the light polymerization activities of the monomers used for experimental composite resins were evaluated by measuring the residual monomer in these cured resins by means of HPLC. The monomer with lower viscosity had higher reactivity than that with higher viscosity.
