Water Uptake of a Silorane-Based Composite Used in Restorative Dentistry

The mechanical properties of the resin-based composites used in restorative dentistry are known to be influenced by the presence of water. The aim of this study was to characterize in vitro the parameters of water uptake of a silorane-based composite (SBC). Polymerized discs of one SBC (Filtek Silorane(A (R))), two different resin-based composites (RBCs: Grandio(A (R)), G, and Tetric(A (R)), T), and a compomer (Hytac(A (R)), H), either immersed in distilled water or held in dried air, were compared. Specimens were weighed over one year, and variations in their weight, the kinetics of water uptake, and the diffusion coefficient D were determined. The equilibrium time was one week for the two RBCs, about two months for the SBC, and about six months for the compomer. The water uptake was in the range of 17-21mg/mm(3) for the SBC and the compomer, but about 8 mg/mm(3) for the RBCs. The values of D (10(-12) m(2) s(-1)) were 15.96 for the SBC, 23.26 for G, 45.87 for T, and 27.39 for H. The SBC showed a decrease in the diffusion coefficient, its equilibrium time was about two months, and its total water uptake was close to that of the compomer.