Objective: To develop a low shrinkage, hydrophobic, degradation-resistant, antimicrobial dental composite using a fluorinated acrylate, and a difunctional oxirane. Methods: The effects of a fluorinated acrylate (2-(perfluorooctyl)ethyl acrylate; PFOEA), a difunctional oxirane (EPALLOY™ 5001; EP5001), and a three-component initiator system (camphorquinone/ethyl 4-dimethylaminobenzoate/4-Isopropyl-4′-methyldiphenyl iodonium Tetrakis (pentafluorophenyl) borate; CQ/EDMAB/Borate) on bisphenol A glycidyl dimethacrylate: triethylene glycol dimethacrylate (BisGMA:TEGDMA) composite surface hardness, degree of monomer-to-polymer conversion, hydrophobicity, translucency, mechanical properties, polymerization shrinkage and shrinkage stress, degradation, water imbibition, and antimicrobial properties were determined. Results: Overall the experimental composites had comparable mechanical properties and lower volumetric polymerization shrinkage and shrinkage stress as compared to BisGMA:TEGDMA controls. Addition of PFOEA increased composite hydrophobicity, but it decreased degree of cure, ultimate transverse strength, and translucency. It also decreased polymerization shrinkage and shrinkage stress. The use of the CQ/EDMAB/Borate initiator system was beneficial for the cure and mechanical properties of the 30% w/w PFOEA group. However, it decreased the hydrophobicity and translucency of those composites. The addition of EP5001, at the low concentration used in this work, did not contribute to reduced polymerization volumetric shrinkage or antimicrobial properties, but it did reduce shrinkage stress. Conclusions: A mechanically viable hydrophobic composite system with reduced polymerization shrinkage and shrinkage stress has been developed by adding PFOEA and EP5001. However, the addition of EP5001 did not render the composite antimicrobial due to the low concentration used. Further research is needed to determine the lowest concentration at which EP5001 provides antimicrobial activity. The composites developed here have the potential to improve longevity of traditional BisGMA:TEGDMA composite systems.
