Eight different cross-linking agents were added to the monomer component of a linear poly(methyl methacrylate) denture-base resin in various concentrations, and their effect on the impact resistance of the cured polymer studied. The cross-linking agents were chosen to provide a range of cross-linking chain lengths and degrees of chain flexibility. When tested under oral conditions, the polymers cross-linked with long and flexible chains did not show the marked reduction in impact resistance found in polymers cross-linked with shorter and stiffer cross-linking chains. It seems likely that by replacing EGDMA in denture-base resins with a cross-linking agent such as PEG 600 DMA, one could use a higher concentration with a consequent improvement in solvent resistance.
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