Temperature and dimensional changes in the two-stage processing technique for complete dentures

Objectives: This study concerned the temperature and linear dimensional change of heat-cured acrylic resin in the two-stage processing technique for complete dentures. Methods: Thermocouples were incorporated in the acrylic resin for recording temperatures. Measurements between reference marks were made by a high-resolution digital measuring microscope. Results: No increase in temperature associated with the exothermic nature of the polymerization reaction was recorded. The temperature of the resin followed the waterbath temperature closely. The temperatures recorded at various regions were in phase with each other. The total linear shrinkage of the base after two processing cycles was less than 1% and compares favourably with studies on the single-stage processing technique. Conclusions: Temperature differential is excluded as a reason for the warpage of dentures. The dimensional changes of the denture base resulting from the two-stage processing technique cannot be considered to be of any clinical significance.