Effect of resin stages on the dimensional accuracy of denture bases

Abstract

The purpose of this study was to verify the dimensional accuracy of denture bases influenced by acrylic resin stages, cured in water bath cycle, in relation to flasking methods. Thirty wax maxillary bases were made and randomly assigned into 2 groups of 15 specimens according to the flasking method used. Each group was subdivided into 3 groups of 5 specimens, and the acrylic resin was used at its stringy, doughlike and rubbery stages. The acrylic resin dough was pressed in metallic flasks by the conventional and RS systems and submitted to the water bath curing cycle at 74°C for 9 hours. After cooling at room temperature the resin bases were removed from flasks, finished and fixed on stone casts with instantaneous adhesive. The resin base-stone cast sets were transversally sectioned into 3 sections and the base-stone gap measured at 5 points in each section. The results were submitted to ANOVA and Tukey’s test and showed that the use of the acrylic resin at its stringy, doughlike and rubbery stages presented statistically significant different values, with lower discrepancies for the RS system packing method. The best results were observed in section A and the worst in section C in both packing methods.