Evaluation of surface roughness and color change of a light-cured and a heat-cured acrylic resin employed for fabrication of prosthetic bases after exposure to different types of disinfectants

Abstract

This study evaluated the changes in surface roughness and color of materials employed in the fabrication of prosthetic bases after immersion in disinfectants. Sixty specimens were fabricated using a round matrix; half of the specimens were fabricated with a heat-cured composite resin, and the other half with a light-cured composite resin. After polishing, the specimens were stored in distilled water at 37ºC from 48 to 52 hours, and then submitted to initial tests of surface roughness and color. The specimens were randomly divided into three groups and immersed in the following chemicals: G1 (1% sodium hypochlorite for 10 minutes), G2 (5.25% sodium hypochlorite for 5 minutes) and G3 (2% acidic glutaraldehyde for 10 minutes). The surface roughness and color tests were once again performed and the specimens were then stored in deionized water at 37ºC for 6 days. On the seventh day, the immersion was repeated; this procedure was performed at every 7 days during 1 month and the tests were repeated after the fourth week. The results were submitted to three-way analysis of variance (ANOVA) and to the Tukey test. Within the same groups of specimens, statistically significant differences were only observed for the light-cured resin, which presented slight changes after exposure to 5.25% sodium hypochlorite and 2% glutaraldehyde for the interval ?E2, which indicates differences in reading values between immersion after 30-day storage and the first immersion in the disinfectants.