Fatigue characteristics of a high-strength porcelain.

The purpose of this study was to determine stress corrosion fatigue characteristics of Optec-hsp porcelain. Disks (1 mm thick and 12 mm in diameter) were prepared according to the manufacturer's firing recommendations. Samples were subjected to dynamic loading at multiple constant stressing rates. Dynamic fatigue was measured using a biaxial flexural strength test in a circulating bath. Inert strength was determined in a moisture-free environment. The mean fracture strength for the dry (moisture-free) samples was 167.9 MPa. Linear regression analysis of log fracture strengths vs log time to failure was performed to obtain fatigue parameters. For Optec, the n-value was 26 (SE 1.9) and sigma f0 was 91.3 MPa (SE 1.2 MPa).