Water sorption and mechanical properties of light-cured proprietary composite tooth restorative materials

Seven light-cured proprietary composite restorative materials, P-50 (3M), P-10 (3M), P-30 (3M), FulFil (Caulk), Herculite (Kerr), Silux Plus (3M) and Silux (3M) were characterized in terms of water uptake at 37 degrees C. For several of the systems, elastic modulus and glass transition temperature were evaluated with a dynamic mechanical analyser (Autovibron DDV-II-C). Model systems such as bis-GMA (75%) + triethylene glycol dimethacrylate (25%), bis-GMA (30%) + triethylene glycol dimethacrylate (10%) + lithium aluminium silicate (60%), bis-GMA + triethylene glycol dimethacrylate (14%) + barium glass (silanated) (86%) and bis-GMA + triethylene glycol dimethacrylate (14%) + zinc glass (silanated) (86%) were also studied with reference to water sorption. It was concluded that the changes in elastic modulus tend to confirm the hypothesis that the matrix-filler interface contains water. Silux and Silux Plus accommodated the greatest amount of water at the interface. Silux Plus displayed a dramatic reduction in elastic modulus c. 0 degrees C, indicating possible melting of water clusters. It appeared that the only available hole for water clusters was at the matrix-filler interface.