Objective To compare the difference in strength degradation and morphology damage of two dental ceramic materials after Hertzian contact cyclic fatigue. Methods Hertzian contact technique was used to investigate the response of EmpressⅡglass ceramic and GI- Ⅱglass- infiltrated alumina ceramic to cyclic fatigue. Critical loads of specimens after different fatigue cycles were recorded. Results For EmpressⅡglass ceramic, critical load had significantly difference between specimens after 105 cycles loading. No significant difference of critical load was found in GI- Ⅱglass- infiltrated alumina ceramic after cycles loading. Conclusion GI- Ⅱglass- infiltrated alumina ceramic has better capability in resistance to cyclic loading. It may attribute to microstructure of material. EmpressⅡglass ceramic shows a brittle damage model.
