Exotherm behavior of the polymer-based provisional crown and fixed partial denture materials

Objectives: The objective of this in vitro study was to evaluate the exothermic reaction during polymerization of the polymer-based provisional crown and fixed partial denture materials. Methods: Three dimethacrylate-based materials and one monomethacrylate-based material were selected. The specimens were pre-conditioned to 23 °C. Temperature changes of the materials during polymerization were recorded in a model test-cavity overlying a type K thermocouple. Peak temperature, time to reach peak temperature and total peak area were determined. The data were statistically analyzed using one-way ANOVA at a significance level of 0.05. Results: All materials exhibited exotherm release ranging from 5.1 to 12.7 °C. Trim gave a peak temperature that was not significantly lower (p>0.05) than those of Protemp 3 Garant and Luxatemp, but fast set Temphase showed a significantly higher (p<0.05) peak temperature than the other materials. All materials showed no significant differences (p>0.05) in the total peak area. Trim showed the slowest exotherm reaction; its time to reach the peak temperature was ca. 10 min after mixing, while ca. 2 min for the other materials. Significance: The dimethacrylate-based materials (except for fast set Temphase) exhibited no significant differences in peak temperature and total peak area from the monomethacrylate-based material with slower exotherm reaction. A reformulation of the dimethacrylate-based materials could be envisaged to generate a material with a slightly slower setting and a reduced peak temperature.