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Six different cross-linking agents were added to the monomer component of an autopolymerizing denture base resin, and their effects on the water sorption and solubility were investigated. The results of this study suggested that the chemical nature of the polymer versus that of the water molecule directly affected the water sorption of denture base resin. The addition of a cross-linking agent decreased the solubility with increasing concentration.

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The authors investigated the composition and structure of six hard auto-polymerizing reline resins. The chemical compositions, glass transition temperatures, molecular weights and particle size distributions of the powders, and the chemical compositions of the liquids were examined. The powder compositions were classified into three groups. The first group contained poly(methyl methacrylate). The second contained poly(ethyl methacrylate) and poly(methyl methacrylate/ethyl methacrylate) and the third contained poly(ethyl methacrylate). The average molecular weights of these powders was about 2 x 10(5). The indexes of molecular weight dispersion suggested that all powders contained polymers that had a narrow molecular weight distribution. The particle size distribution of these powders was classified into two groups. The first group was mainly in the range of 50-100 microns and the second mainly between 20 and 50 microns. The composition of the liquids was classified into three groups. The first group contained a monofunctional methacrylate monomer. The second contained a monofunctional methacrylate monomer and a plasticizer and the third contained monofunctional methacrylate monomers and cross-linking agents. The results of this experiment showed the differences in composition among the products. This will be useful for examining the relationship between the composition and mechanical properties of hard autopolymerizing reline resins.