Surface roughness and Candida albicans biofilm formation on a reline resin after long-term chemical disinfection and toothbrushing.

STATEMENT OF PROBLEM: Routine cleaning of a denture may increase the surface roughness of the material. PURPOSE: The purpose of this study was to investigate the effect of denture cleansers and time on the roughness and Candida albicans biofilm formation on a reline resin. MATERIAL AND METHODS: Specimens of Tokuyama Rebase Fast II (20 x 10 x 2 mm) were prepared and divided into 9 groups (n=15): Test groups were toothbrushed (30 cycles per day) in 1 of the following solutions: water, soap, or toothpaste. After toothbrushing, the specimens were immersed in solutions of water, sodium perborate, or chlorhexidine. These treatments were done once a day for 365 days. The surface roughness was evaluated at 0, 7, 15, 30, 90, 180, 270, and 365 days, and the C albicans biofilm formation was measured after 365 days. The roughness data were analyzed by 3-way repeated measures ANOVA and the Tukey test (alpha=.05), and the C albicans biofilm formation was analyzed by 2-way ANOVA. RESULTS: Significant differences were found in the toothbrush and time interaction and in the toothbrush, immersion, and time interaction (P<.001). No significant differences were found between the toothbrush agent and chemical disinfection (P=.085) or between chemical disinfection and time interaction (P=.604). Brushing with dentifrice (PPb and PCh) showed a gradual decrease in surface roughness. The comparison among groups showed that PCh produced the lowest values of roughness. For C albicans biofilm formation, no significant differences were found among the experimental groups. CONCLUSIONS: The roughness values ranged from 0.31 to 0.69 mum for all evaluated groups. For all groups, no significant differences were found in the quantification of C albicans.