Effect of repeated simulated disinfections by microwave energy on the complete denture base adaptation.

This study evaluated the effect of repeated microwave disinfections on the adaptation of the maxillar denture base using 2 different flask closure methods. Twenty stone cast-wax base sets were prepared for flasking by traditional cramp or RS system methods. Five bases for each method were submitted to 5 repeated simulated disinfections in a microwave oven with 650W for 3 minutes. Control bases were not disinfected. Three transverse cuts were made through each stone cast-resin base set, corresponding to canine, first molar, and posterior region. Measurements were made using an optical micrometer at 5 points for each cut to determine base adaptation: left and right marginal limits of the flanges, left and right ridge crests, and midline. Results for base adaptation performed by the flask closure methods were: traditional cramp (non-disinfected = 0.21 +/- 0.05mm and disinfected = 0.22 +/- 0.05mm), and RS system (non-disinfected = 0.16 +/- 0.05 and disinfected = 0.17 +/- 0.04mm). Collected data were submitted to ANOVA and Tukey test (alpha=.05). Repeated simulated disinfections by microwave energy did not cause deleterious effect on the base adaptation, when the traditional cramp and RS system flask closure methods were compared.