Fatigue failure parameters of IPS-Empress porcelain

The purpose of this study was to determine the stress corrosion fatigue characteristics of a heat-pressed ceramic material, IPS-Empress. Disks (1 mm thick, 12 mm in diameter) were prepared, polished, and subjected to dynamic loading at multiple constant stressing rates. Fatigue tests were conducted in a circulating bath using a biaxial flexure test. The inert strength of the samples was determined in oil. The mean fracture strength for the inert tests was 135.7 MPa. Linear regression analysis of log fracture strengths vs log time to failure was performed to obtain fatigue parameters. For IPS-Empress the n value was 31 (SE 3.5) and sigma f0 was 83.3 MPa (SE 1.3 MPa).