2024 Volume 37 Issue 2 Pages 155-163
Objective : To measure the fatigue strength of commercially available implants by subjecting three different implant abutment connections to cyclic loading tests.
Methods : The three connection mechanisms used were the external joint (EXT), internal joint (INT), and taper joint (TAPER) systems. In addition, two types of commercially pure titanium (ASTM Grade 4) one-piece implants were prepared and used as controls ; the first was a solid type (Cont.) and the second, a hollow structure with a φ2.24 mm central axis (Cont. H).
The test specimens were mounted on a 30° inclined block and then placed in a fatigue testing machine. Cyclic sinusoidal loads were applied at 10 Hz, and the load and deformation of the test specimens were measured for each load cycle. The cyclic loading continued until the test specimen failed or reached five million cycles. If a test specimen failed, another specimen was retested using a 100 Nmm lower bending moment. The maximum load value achieved in five million cycles was considered the maximum fatigue load.
Results : The results of the cyclic loading test showed that the maximum fatigue loads for Cont., Cont. H, EXT, INT, and TAPER were 164, 55, 200, 237, and 291 N, respectively. The corresponding bending moments were 900, 300, 1,100, 1,300, and 1,600 Nmm.
Conclusion : The results of the fatigue tests of cyclic loading showed that INT had approximately 18％ higher fatigue strength than EXT, while TAPER had about 45％ higher fatigue strength than EXT. While these results may not be universally applicable to all implant systems, they suggest that the type of connection mechanism is an important factor for selecting implant systems from the perspective of preventing fatigue fractures.
