Effect of Thermocycling on Microhardness of Three CAD/CAM Provisional Materials

Author(s): Mohammad Mahdi Tavajoh, Farzan Younesi, Solmauz Eskandarion

Purpose: This study aimed to evaluate and compare the surface Microhardness of three CAD/CAM provisional restorative materials before and after Thermocycling.

Materials and Methods: In this in-vitro study, ten rectangular specimens (12 × 13 × 1.5 mm) were prepared from each of the following CAD/CAM provisional materials: Structur CAD (VOCO GmbH, Germany), Telio CAD (Ivoclar Vivadent, Liechtenstein), and Vita CAD Temp Monocolor (Vita Zahnfabrik, Germany). Surface Microhardness was measured using the Vickers test (20 g load for 10 seconds). All specimens underwent 5,000 thermal cycles between 5°C and 55°C to simulate six months of clinical service. Post-cycling Microhardness was measured, and results were statistically analyzed using Repeated Measures ANOVA.

Results: Before Thermocycling, Telio CAD exhibited significantly higher Microhardness compared to Structur CAD and Vita CAD Temp (p < 0.05). After Thermocycling, differences among the three groups were not statistically significant (p > 0.05). Telio CAD and Structur CAD showed a significant decrease in surface Microhardness post-Thermocycling, while Vita CAD Temp did not show a statistically significant change.

Conclusion: Thermocycling affected the surface Microhardness of CAD/ CAM provisional materials differently. While initial hardness varied among the materials, all showed comparable performance after simulated clinical aging. For temporary restorations lasting up to 6 months, none of the tested materials demonstrated a clinically superior advantage in terms of surface microhardness.