Infrared Thermographic Evaluation of Exothermic Temperature Changes During the Setting Reaction of Six Dental Impression Gypsums: An In Vitro Linear Regression Model

Objective: To evaluate surface temperature changes during the setting reaction of six dental gypsums using infrared thermography. Methods: This experimental in vitro study evaluated six dental gypsum materials randomly allocated into six groups: three Type IV materials (Elite Rock, Dürum, and Velmix) and three Type III materials (Elite Model, Pentadur, and Duromix). Specimens were manually mixed for a few minutes using a gypsum spatula and a rubber mixing bowl and subsequently formed in triangular stainless-steel molds with a 2 cm base and 2 cm equal sides. Thermographic evaluation was performed using a Fluke TiS55+ infrared camera. Surface temperature measurements were recorded for each specimen at baseline and at 10 and 25 min. Results: Distinct thermal profiles were observed among the dental gypsum materials. Compared with the baseline, Type IV dental gypsum showed an increase in temperature of 1.05 °C at 10 min (95% confidence interval [CI]: 0.23–1.87; p = 0.012) and 2.46 °C at 25 min (95% CI: 1.64–3.28; p < 0.001). Compared with Elite Rock, the reference material, Dürum and Velmix showed significantly lower temperatures, with differences between −2.94 °C and −2.47 °C, respectively (both p < 0.001). Type III dental gypsum showed an increase in temperature of 6.16 °C at 10 min (95% CI: 5.50–6.82; p < 0.001), followed by an increase of 1.76 °C at 25 min (95% CI: 1.10–2.42; p < 0.001). Conclusions: Type III dental gypsums exhibited marked early increases in temperature, whereas Type IV dental gypsums showed more gradual and material-specific thermal patterns. These findings demonstrate differences in the thermal behavior of the evaluated dental gypsum materials during the setting reaction and support further investigation into the relationship between thermal behavior and other physicochemical properties, including dimensional stability and material performance.