Thermal Influence on the Mechanical Properties of CAD/CAM Ceramics: A Systematic Review

Aim: The influence of different heat treatments on the mechanical properties of CAD/CAM ceramics was assessed. Methodology: A systematic search in five databases and gray literature was performed. In vitro studies providing data about the influence of various thermal treatments on the mechanical properties of CAD/CAM ceramics were included. Results: Out of 6500 articles found, 15 were included for results analysis. In the disilicate group, e.max CAD showed the best results in flexural strength (FS) and Vita Suprinity in microhardness (MH) and fracture toughness (FT). In the zirconium oxide group, Incoris exhibited better performance in FS while Razor Zirconia demonstrated superior MH and FT. Eleven studies had low and four had a moderate risk of bias (RoB). Conclusions: Both reinforced vitreous ceramics and zirconia ceramics, when subjected to high temperatures for short periods of time, significantly improve their mechanical properties. Favoring the biomechanical behavior of restorations present in the oral cavity, they are always subjected to constant changes in temperature, forces of different nature, intensity, or direction, changes in acidity, presence of moisture, etc., which make this a difficult environment for their clinical survival.