Development of an Oxirane-acrylate Dental Composite System

A restorative composite composed of an interpenetrating network system with an oxirane based resin and meth-/acrylate monomers system will be developed. Oxirane (epoxy) monomers polymerize by a ring-opening mechanism following a cationic initiated mechanism while acrylic compounds propagate via a free radical polymerization. A ring opening pathway aids in reducing inherent shrinkage of the cured resin. High biocompatibility of the oxirane resin adds another benefit of applying the polymer composites as in vivo oral implants. The monomers will be photo-cured by visible light using an initiator system that produces highly reactive cations and radicals.

Oxirane-acrylate resin system without an inorganic nanoparticle reinforcing filler will first be studied to determine optimal ratios of monomers and cationic/free-radical photo-initiators to achieve significant cure under clinical conditions. Addition of a suitable reinforcing glass filler to the resin system will be the next step. Further investigation of this composite will proceed to achieve desired cure rates as well as adequate mechanical properties. Various monomers and different initiator ratios will be evaluated as well to determine the best candidates.

Mechanical and physical tests such as Rockwell15T hardness, contact angle, and 3-point bend tests will be done to characterize the specimens. Finally, several fluoro-acrylate compounds will be tested for their effects in improving hydrophobicity to aid in decreased water sorption and contribute to longevity of the composite. Antimicrobial activity will also be determined.

At the end of the project, we developed a hydrophobic composite with good physical and mechanical properties compared to a bisphenol-A glycidyl methacrylate control. This composite also showed significant anti-microbial properties.