Water absorption characteristics of dental microfine composite filling materials. I. Proprietary materials

Long-term water absorption characteristics have been studied for four microfine composite filling materials over a period of some three years. By measuring gravimetrically the kinetics of successive absorption/desorption cycles, equilibrium uptake, diffusion coefficients, and solubility data have been obtained. Equilibrium uptake and solubility data are best rationalized if expressed as volume/volume rather than weight/weight. Diffusion coefficients were similar to those obtained previously for conventional composites.