Effect of Implant Diameter and Length on Stress Distribution for Titanium and Zirconia Implants by Using Finite Element Analysis (FEA)

Purpose: The purpose of this study was to analyze stress distribution patterns in implant restorations created in different length and diameter made of titanium and zirconia by using three dimensional finite element analysis (FEM) with straight and 15° angled abutment. Materials and Methods: For titanium models; Ti-6Al-4V for implant fixture, connection element and abutments (straight and 15° angled abutment), yttrium tetragonal zirconium polycrystal (Y-TZP) for zirconium framework, Felds phatic porcelain for superstructure material and for zirconia models; Y-TZP for implant fixture, connection element, abutments (straight and 15° angled abutment) and zirconium framework, Felds phatic porcelain for superstructure material were used. The implants and their superstructures were modeled using CAD software Creo Elements-Pro5.0 and the mandibula was modeled using MIMICS 13.1 software. Optimum finite element modelled was obtained using 3-matic segmentation of MIMICS. The solid models of mandibular incisors were transferred to mesh model in FEM (ANSYS/Workbench 12.1) to analyze. The models simulated implants were placed in vertical position in the lost incisor of anterior mandible. First model simulated the titanium and zirconia implants with a diameter of 3.8 mm and lengths of 9.0 mm, 10.5 mm, 12.0 mm and 15.0 mm for each model. Second model simulated titanium and zirconia implants with a diameter of 4.6 mm and lengths of 9.0 mm, 10.5 mm, 12.0 mm and 15.0 mm for each model. Third model simulated titanium and zirconia implants with a diameter of 5.8 mm and lengths of 9.0 mm, 10.5 mm, 12.0 mm and 15.0 mm for each model. This process was repeated for implants with 15° angled abutment. Loading of implants, respectively in an axial, a lingual and a mesiodistal direction with average masticatory forces of 114.6 N, 17.1 N and 23.4 N simulated in an oblique direction. The values of equivalent Von Mises Stress at the implant-bone interface were calculated for all variations using finite element analysis. Results: A comparison between titanium and zirconium implants with maximum stress for implants of the same length but different diameters, same diameters with different lengths and straight and 15° angled abutment showed nearly similar variances. Conclusion: With in the limitations of this study, increasing implant diameter is better than decreasing implant diameter both for titanium and zirconium models but raising implant length is worse than decreasing implant length with applied masticatory forces.