The Influence of Fluorinated Divinyl Urethane Monomers and Fluorinated Fillers on Resin Composite Physical Properties and Chemical Biostability

Background: Salivary enzymes contribute to loss of resin composite material integrity and release of degradation products, suggesting that improving composite physical and chemical stability is required. Objectives: To study fluorine/urethane incorporation into resin composites and assess their influence on enzyme-mediated ester hydrolysis and mechanical strength. Methods: Fluorinated monomers and silanated barium borosilicate fillers were prepared and characterized by 1H-NMR [monomers] and thermogravimetric analysis (TGA)/X-ray photoelectron spectroscopy (XPS) [fillers], respectively. Composite formulations were assessed for mechanical strength, hydrophobicity, and biodegradation resistance using simulated human salivary esterase incubation conditions and ultra-high-performance liquid chromatography. Results: Eight different fluoro-monomers were assessed after incorporation into resin formulations at 35-55wt%. The best performing monomer was used alongside a fluoro/methacrylate silane and showed comparable mechanical/hydrophobicity properties but lower biostability relative to the control. Increasing the fluoro-contribution showed an optimum between reduced physical properties and improved biostability. Conclusions: Novel monomers should seek to remove/replace all vulnerable ester-containing monomers.M.A.S