Influence of polymerization techniques on denture base accuracy

Abstract

The purpose of this study was to verify denture bases accuracy, made with heat-cured acrylic res- in, under the influence of three po- lymerization cycles: conventional, dry heat and microwave energy. Thirty pattern casts were made with plaster stone from a rubber mold representing a normal eden- tate arcade. The experimental bas- es were made on the casts, which were divided, randomly, into three groups of ten elements each, being included in flask by the conven- tional technique. After the polym- erization and finishing, the resin bases were afixed on their casts with instantaneous adhesive. The plaster model-prosthesis set was positioned and afixed on a especific equipment to obtain the sections. Guided by instruments on fixation grip, with the aid of a manual saw, three saggital plane cuts were made on the region corresponding to the right (A) and left (C) crest of the ridge, on the palatal median region (B), and three lateral plane cuts corresponding to the distal of right and left canines (A), mesial of right and left first molars (B) and post dam region (C). The dimen- sional alteration occurred on the acrylic resin was evaluated with a comparative microscope in five referential points demarcated in each kind of cut. The numerical results were submited to a statisti- cal analysis and to the Tukey’s test to a significance level of 5%. All the evaluated techniques caused distortions, without significative statistical difference. There was no significative statistical difference on the lateral and saggital plane cuts, among the three studied polymerization techniques. When the maladjustment was analysed within the same techniques, the accuracy was significant among the plane cuts, in a same away. Key words: uper denture base, acrylic resins, types of po- lymerization, accuracy.