Fracture Resistance of CAD/CAM Monolithic Zirconia Crowns Supported by Titanium and Ti-Base Abutments: The Effect of Chewing Simulation and Thermocyclic Aging.

The article focuses on evaluating the effect of chewing simulation and thermocyclic aging on the fracture resistance of CAD/CAM monolithic zirconia crowns supported by titanium (Ti) and titanium base (Ti-base) abutments. In an in vitro study with 40 mandibular first molar crowns, no statistically significant difference in fracture resistance was found between crowns cemented on Ti or Ti-base abutments, nor between aged (chewing simulation and thermocycling) and non-aged groups, with all specimens showing 100% survival after simulated aging. Failure modes primarily involved acrylic block fracture and decementation, while the zirconia crowns themselves showed no cracks or fractures. The study concludes that CAD/CAM monolithic zirconia crowns supported by either Ti or Ti-base abutments demonstrate sufficient fracture resistance for single posterior tooth replacement, though further long-term clinical studies are recommended to confirm these findings.