Multi-directional Fatigue Test of Dental Implant System

Objectives: Basically, fatigue of dental implant system has characterized with sinusoidal cyclic loading based on the ISO 14801 standard, which only can be applied single loading force to verify their dynamic fatigue. To obtain further mechanical properties of implant system, this study examined fatigue test with multi-directional loading as a masticated simulation.
Methods: A total of 12 dental implant system were fixed in the specified loading jig to apply masticated loading force, and loaded up to occur fracture on certain cycles per ISO 14801 standard. The value of dynamic vertical force has fixed from 80 % of static fracture load. A test was carried out using a Force 5 (AMTI, Massachusetts, US) multi-directional simulator, group 1 has applied single vertical loading (30°, 15 Hz) while the group 2 has simultaneously applied multi-loading with mesiodistal (±15°, 1 Hz), faciolingual (±15°, 1 Hz), and vertical direction (15 Hz). For the fatigue limit between single and multi-directional loading, the fracture cycles were measured from this testing results, paired t-tests were used for significance of two groups (p<0.05).
Results: Number of failures and failure rates per cycle differed significantly between two groups, fatigue limit was higher at single directional loading (group 1), than that of group 2 (p<0.05).
Conclusions: Fatigue failure was significantly more likely with multi-directional loading. Applying of multi-direction needs to try to get more failure information from the point of giving a masticated simulation.