Materials and methods: Three types of provisional restorative materials produced for CAD-CAM systems were examined: Vita CAD Temp (Vita Zahnfabrik, Germany), Telio CAD (Ivoclar Vivadent, Liechtenstein) and Ceramill Temp (Amann Girrbach, Austria). A total of thirty disc specimens with 2 mm thick and 10 mm diameter were produced (n=10). Vickers hardness was measured under a load of 10g for 10s. All specimen groups were subjected to 5000 thermo cycles and hardness measurements repeated. One-way ANOVA and post hoc Tukey’s test were used for statistical analysis.

Results: Hardness values (HV) of CAD-CAM provisional materials decreased after thermo-cycling, however, it was not statistically significant (p>0.05).

Conclusion: Thermo-cycling affects the hardness of CAD-CAM provisional materials tested. Thermo-cycling was directly related to the reduction of microhardness values for the CAD Temp and Ceramill Temp. These findings may support clinicians to advice patients who have to use temporary restorations for a long time to avoid thermal changes in the mouth.