THE INFLUENCE OF COMONOMER COMPOSITION ON DIMETHACRYLATE RESIN PROPERTIES FOR DENTAL COMPOSITES

During the polymerization of multifunctional monomers for dental resto rations, typical final double-bond conversions range from 55 to 75%. T he low conversion results in a large amount of extractable monomer, re duced adhesion to the filler, and the potential for increased swelling . In this work, the ability to increase the maximum conversion by opti mizing the copolymer composition is explored. A series of multi-ethyle ne glycol dimethacrylate monomers of various lengths was used as a mod el system to determine how the copolymer composition affects the final conversion, the mechanical properties, and the predicted shrinkage. I t was found that the ultimate conversion can be significantly increase d, shrinkage decreased, and mechanical properties maintained. It was f ound that up to 30 wt% of poly(ethylene glycol) 600 dimethacrylate cou ld be added to diethylene glycol dimethacrylate without reducing the s trength and increasing the conversion. Results for other comonomer com binations were similar.