Fluorinated bis-GMA as potential monomers for dental restorative composite materials

Bisphenol A-glycidyl methacrylate (bisGMA) is one of the most widely used monomers in the preparation of dental restorative composite resins. However, this monomer has high viscosity and high hydrophilicity, leading to high volume shrinkage and high water content of the resulting dental restoratives after polymerization. We hypothesized that the viscosity and hydrophilicity could be dramatically reduced by transforming the hydroxyl groups of bisGMA into fluorinated esters. To test this hypothesis, we synthesized a new fluorinated bisGMA analogue (perFB-bisGMA) through the esterification of bisGMA with perfluorobutyryl chloride. The chemical structure of perFB-bisGMA was confirmed by NMR and STIR studies. PerFB-bisGMA had a much lower viscosity and much higher hydrophobicity than bisGMA. BisGMA and perFB-bisGMA were copolymerized through light-initiated polymerization. With the increase of perFB-bisGMA content, the mechanical properties of the copolymers were not negatively affected, yet the polymerization shrinkage was reduced, and the hydrophobicity of the copolymer was increased, suggesting that fluorinated esters of bisGMA could be attractive candidates to copolymerize with bisGMA for dental restorative applications.