In this study, gamma rays were used for the first time to cure dental-base material. The effect of the radiation dose on the thermal and theological properties of poly(methyl methacrylate) (PMMA) used as a dental-base material was investigated. The commercial powder and liquid material (heat-curing-grade) were mixed and polymerized at 60 and 70 degreesC in a constant-temperature water bath for 30 min and then were cured by gamma rays, with total doses of 7.5, 15, 22.5, 30, 45, 52.5, 360, and 2160 krad. For each sample, the viscosity-average molecular weights were measured, and no significant differences were observed of total dose on molecular weights. A thermal investigation with differential scanning calorimetry showed an exothermic peak in the thermograms of samples that were not completely polymerized and crosslinked. The rheological nature of the samples was studied with dynamic mechanical analysis. A comparison of properties of gamma -ray-cured samples and those cured by other methods revealed gamma curing to be a superior method for producing high-molecular-weight homogenous polymers with low porosity and crosslinking. (C) 2001 John Wiley & Sons, Inc.