[Water sorption and desorption on experimental composite resins]

The water sorption and desorption, and the diffusion coefficients of the water sorption and desorption were studied on the experimental composite resins with various filler contents in both chemically-cured and light-cured type. As the filler content increased, the rate of the water sorption and desorption on the composites decreased. And these properties associated with the prediction obtained from the law of mixture. The filler did not absorb water, so the effect of the filler content on the diffusion coefficients of the water sorption was to be associated with of the law of mixture. However, in the diffusion coefficients of the water desorption the effect of filler content could not be proved to be associated with the law of mixture. The diffusion coefficients of the water desorption were over 2 times larger than the those of the water sorption.