Three-Dimensional Deformation and Wear of Internal Implant-Abutment Connection: A Comparative Biomechanical Study Using Titanium and Zirconia

Purpose: The aim of this study was to investigate the influence of the abutment material and the connection geometry on deformation and wear at the internal implant-abutment connection area (IAC), using an optical scanner. Materials and Methods: Thirty-two internal conical titanium implants, and two types of prefabricated abutments (zirconia or titanium), each (n = 8) with different connection geometries (hexagon or nonhexagon) were prepared. The inner surfaces of the implants were optically scanned before and after loading for 100,000 cycles in a simulated wet environment. The scanned data were superimposed to calculate potential three-dimensional (3D) deviations. Surfaces of the two respective implants in each group were examined using scanning electron microscopy to observe fretting wear patterns. A two-way analysis of variance (ANOVA) was used for the statistical analysis. Results: The 3D deviation (deformation) was detected at the IAC in relation to the loading direction. The average 3D positive deviation and maximum positive and negative deviations at the IAC were significantly higher with zirconia abutments than with titanium abutments, regardless of connection geometries (all P .05). However, the average 3D negative and standard 3D deviations were similar between the two materials (both P > .05). The effect of connection geometry was not significant (P > .05). After cyclic loading, an irregular wave-pattern furrow was observed on the connection area of the implant with the titanium abutment, whereas a long and straight groove was detected on that with the zirconia abutment. Conclusion: Based on this analysis, the deformation and the wear at the IAC could be significantly affected by the material of the prefabricated abutment. Keywords: deformation, implant-abutment connection, prefabricated abutment, titanium, wear, zirconia