Effects of material and coefficient of friction on taper joint dental implants

The aim of this study was: (1) to compare the coefficients of friction between commercially pure titanium (cpTi), titanium (Ti) alloy, and yttria-stabilized zirconia (YSZ) and: (2) to investigate the dynamic behavior of an implant system before, during, and after loading, by transient dynamic three-dimensional finite element analysis (FEA). Coefficients of friction were measured by a ball-on-disk frictional wear testing device. The preload in the screw shaft was calculated from geometric parameters. Two abutment model designs were created, namely a Ti alloy abutment model with a porcelain-fused-to-metal super structure and a YSZ abutment model with a porcelain-fused-to-zirconia super structure. Transient dynamic three-dimensional FEA was performed on ANSYS Workbench Ver. 15.0. The coefficients of friction of YSZ/cpTi, YSZ/Ti alloy, Ti alloy/cpTi, and Ti alloy/Ti alloy were 0.4417, 0.3455, 0.3952, and 0.3489, respectively. The preload generated in the abutment screw of the FEA model was set to be 158 N. Significantly differences were not found in the maximum von Mises equivalent stress between the Ti alloy and YSZ abutment models before, during, and after loading. The findings indicate differences in the coefficients of friction of cpTi, Ti alloy, and YSZ before, during, and after loading. Fractures caused by stress did not depend on the use of different materials (Ti alloy and YSZ) at the abutment.