Fatigue characteristics of five types of implant-abutment joint designs

This study evaluates the fatigue limits for five implant-abutment combinations. Each implant-abutment system was tightened with a closing torque of 32 N-cm. The test specimen was loaded at an inclination of 30 degrees with respect to the loading axis after fixing it 11 mm away from the fixed point. A cyclic compression load was applied at loading cycles of 10 Hz using a hydraulic dynamic testing machine (Model 8516, Instron, USA). The highest and lowest mean static strength was observed in the EXZRTS (1772.2 N) and INTIWS (893.8 N), respectively. The fatigue limits that guarantee a life of 5×106 cycles ranged from 300 N to 800 N. The mean static strength of the external hex type was higher than that of the internal type. However, the fatigue strength of the internal type was higher than that of the external hex type. The fatigue strength of the external hex type with a zirconia abutment was higher than that with the titanium abutment. Fatigue fracture of the zirconia abutment occurred after crack propagation by chipping in the contact position of the margin.