Acrylic resin for complete denture: effect of polymerization cycles at residual monomer released and porosity evidence

Abstract

The objective of the present work was to study the behavior of four water bath curing cycles of heat activated acrylic resin: cycle I – 65 °C for 30min; 50 °C for 23h and 30min; and 100 °C for 1h; cycle II – 50 °C for 24h and 65 °C for 1h; 30min to elevate at 100 °C and 1h to 100 °C; cycle III – 72 °C for 9h and cycle IV – 65 °C for 1h; 30min to elevate at 100 °C and 1h at 100 °C. The performance of both cycles was evaluated by the quantity of residual superficial monomer and the presence of porosity. The statistical test was based in ANOVA and Tukey test (5%). The results pointed out that the residual monomer presented statistical significant differences in the factor curing cycle. Porosity was verified in minimum degree in the cycle III, in appreciable amount in the cycle IV and neither to cycle I and cycle II. It has been concluded that the short cycle determined the presence of porosity and, for the long cycles, temperature elevation, in the end of the cycle, was important to the reduction of the residual monomer.