Stress Distribution Along the Implant-Bone Interface: A Pilot Study using Finite Element Analysis to Compare Tilted and Non-Tilted Implants under Different Loads

Introduction: This study used finite element analysis to evaluate stress distribution of implants placed at different angulations under two loadings. Stress was measured at the implant-bone interface. Methods: Four models of implant and bone were manufactured via three-dimensional optical scanning and point cloud data extraction. They included implants placed: 1) Without tilt 2) tilted at 15o, 3) tilted at 30o, and 4) tilted at 45o. A tissue-level implant was scanned, and a mandible bone model was extracted from cone-beam computed tomography systems. A 3D model of the implants in the mandible were constructed. The finite element analyses were carried out using simulation software. The physical interaction at implant-bone interfaces during loading were considered through bonded surface-to-surface contacts. Static loading (with axial forces of 150N and 300N) were applied to evaluate the implant-bone model. Results: The amount of stress along the implant-bone interface was greater under 300N loading than 150N loading. The stress along tilted implants were greater than that of non-tilted implants under both 150N and 300N. There was no significant variance among the various angles of implants. The displacements along the tilted implants were larger than those of nontilted implants. The stress distribution along the implant-bone interface increased when the loading increased. Conclusion: The tilted implants presented greater stress distribution. The in vitro stress distribution analysis using FEA will provide clinical guidance for implant placement.