Evaluation of Fracture Resistance of Different Monolithic CAD/CAM-Generated Zirconia Crowns after Artificial Aging-An...

Monolithic zirconia has gained widespread use in prosthetic dentistry due to its superior mechanical properties and aesthetics. However, variations in yttria content affect its fracture resistance, especially after artificial aging, which simulates long-term clinical performance.

Thirty zirconia crowns were fabricated using Cercon-ht (3% Y-TZP), Cercon-xt ML (5% Y-TZP), and Nexzrr-T multi (3% and 5% Y-TZP). Crowns were cemented onto acrylic dies with GIC luting cement and subjected to artificial aging in a steam autoclave (134°C, 0.2 MPa, five hours). Fracture resistance was tested using a universal testing machine, and data were statistically analyzed.

Cercon-ht (3% Y-TZP) showed the highest fracture resistance (6178.00 ± 114.39 N), followed by Nexzrr-T multi (3571.00 ± 171.62 N) and Cercon-xt ML (2178.00 ± 546.70 N). The differences were statistically significant (P < 0.001).

Zirconia with lower yttria content (3% Y-TZP) exhibited superior fracture resistance. Multilayer zirconia (3% and 5% Y-TZP) provided a balance between strength and aesthetics, making it a promising alternative for dental restorations.