Impact of Thermocycling and Artificial Aging on the Flexural Strength and Fracture Resistance of CAD/CAM Dental Ceramics: A Systematic Review and Meta-Analysis

Background: CAD/CAM dental ceramics are widely used for indirect restorations because of their favorable esthetic properties, biocompatibility, and mechanical performance. However, long-term exposure to thermal fluctuations, moisture, and cyclic loading may compromise their structural integrity. This systematic review and meta-analysis evaluated the effect of artificial aging protocols on the mechanical properties of CAD/CAM dental ceramics. Methods: A systematic search was conducted in PubMed, Embase, Scopus, Web of Science, LILACS, Google Scholar, and ProQuest from inception to June 2026. In vitro studies evaluating CAD/CAM ceramics subjected to thermocycling and/or artificial aging protocols were included. The primary outcomes were flexural strength and fracture resistance. Random-effects meta-analyses were performed using standardized mean differences (SMDs) or pooled means with 95% confidence intervals (CIs). Subgroup analyses were conducted according to ceramic category, and sensitivity analyses were performed using a leave-one-out approach. Results: Five studies comprising 16 independent comparisons were included in the flexural strength meta-analysis, while five studies contributed 11 comparisons to the fracture resistance analysis. Artificial aging protocols significantly reduced the flexural strength of CAD/CAM ceramics (SMD = −1.68; 95% CI: −2.28 to −1.08; p < 0.00001). The greatest reduction was observed in zirconia-based ceramics (SMD = −3.31), followed by hybrid/PICN ceramics (SMD = −1.37) and lithium disilicate/lithium silicate ceramics (SMD = −1.25). Feldspathic and glass-based ceramics showed no significant reduction. The pooled fracture resistance after aging was 1312.85 N (95% CI: 1131.59–1494.10 N), indicating that most CAD/CAM ceramics maintained clinically relevant fracture resistance despite aging. Conclusions: Artificial aging protocols adversely affect the flexural strength of CAD/CAM dental ceramics, particularly zirconia-based materials. Nevertheless, fracture resistance generally remains within clinically acceptable ranges. Material composition plays a critical role in determining susceptibility to aging-related degradation, highlighting the importance of ceramic selection for long-term restorative performance.