The effect of three processing cycles on some physical and chemical properties of a heat-cured acrylic resin.

Samples were tested by following three processing methods: two processing cycles recommended by the manufacturer and quick violent boiling. Samples processed by following the recommended cycles showed statistically significant differences with regard to impact strength and Brinnel hardness, but without differences in the expected clinical behavior of the resin. Residual monomer ratio was higher when the boiling point was not reached, which seems to confirm the plasticizing effect of residual monomer. Samples were less brittle and less hard. Violent boiling increased porosity and lessened impact strength.