The biaxial flexural strength and reliability of four dental ceramics — Part II

Objectives: The biaxial flexural strength and reliability of four dental ceramics including: Empress glass ceramic (EM), Cerinate porcelain (CE), Corum porcelain (CO) and Alpha porcelain (AL) were compared. Methods: Twenty disc specimens per material were prepared overglazed and tested. The piston on three ball test was used to test the specimens in a universal testing machine at a crosshead speed of 0.15 mm/min. Weibull analysis provided m-values and the 1 and 5% probabilities of failure. Results: Mean strengths (Mpa ± SD) were: EM, 133.5 ± 21.5; CE, 109.1 ± 11.3; CO, 119.8 ± 19.2; and AL, 68.2 ± 9.9. There was no statistical difference between EM or CO and CO and CE strengths (P > 0.05). Weibull m-values included: EM, 6.60; CE, 10.20; CO, 5.27; and AL, 6.93. Cerinate had the highest m-value (P < 0.01) and good dependability. Conclusion: Empress was not stronger or more reliable than many of the frit materials.