Assessment of flexural strength and color alteration of heat-polymerized acrylic resins after simulated use of denture cleansers.

The purpose of this study was to assess flexural strength and color alteration of acrylic resins immersed in denture cleansers for different periods of time. Rectangular specimens (65 x 10 x 3mm) made from three heat-polymerized acrylic resins (Lucitone 550, QC-20 and Triplex) were assigned to three denture cleansers groups (Bony Plus, Corega Tabs and Efferdent Plus) and a control group (immersion in water). Soaking trials of 15 min and 8 h simulated 30 days of use. Flexural strength testing was carried out with 105 specimens on a universal testing machine. Color alterations were visually assessed by examination of photographs taken from 21 specimens. Flexural strength means (in MPa) were analyzed statistically by analysis of variance and Tukey's test at 5% significance level. There were significant differences (p<0.01) among the resins Lucitone (89.439 +/- 7.962), Triplex (88.024 +/- 5.167) and QC-20 (83.379 +/- 7.153). No significant differences (p>0.05) were found either among the denture cleansers (Bony Plus = 87.693 +/- 6.943; Corega Tabs = 86.955 +/- 7.114; Efferdent Plus = 86.195 +/- 7.865 and control = 86.536 +/- 7.012) or between the soaking periods (15 min = 86.875 +/- 7.625 and 8 h = 87.432 +/- 7.355) throughout the soaking cycles simulating 30 days of use. No color alterations were identified by visual examination. The findings of this study showed that chemical denture cleansers used according to the manufacturers' specifications did not cause flexural strength alterations or color changes in heat-polymerized acrylic resins submitted to soaking cycles that simulated 30 days of use.