Effect of monomer structure on the mechanical properties of light-cured composite resins.

The effects of monomer structure on the mechanical properties of visible light-cured composite resins based on the seven types of aromatic dimethacrylates were investigated. The results of this study suggested that the mechanical properties of the composite resins were dependent upon the chemical structure of the dimethacrylate monomers employed. The composites based on dimethacrylates with hydroxy groups showed a relatively significant decrease in flexural strength, elastic modulus, and compressive proportional limit under wet conditions. The segmental mobility of dimethacrylate monomers considerably influenced the nature of cured composites. Bis-GMA-F-based composite showed superior mechanical properties to a conventional Bis-GMA-based material. The SEM observation of fractured surfaces revealed that failure mainly occurred through the resin matrix of the composite resins.