Systematic biomechanical evaluation of different dental implant materials at various bone stock conditions using a statistical and subject-specific computer-based workflow.

Abstract

This computational study aimed to evaluate the bone-implant interaction of dental implants made from materials with varying Young's moduli under various conditions of bone quality. A subject-specific numerical workflow was developed by integrating boundary conditions obtained from a musculoskeletal multibody simulation (MMBS) into a finite element (FE) analysis of the mandible bone. Implants made from commercially pure titanium (cp-Ti), zirconia ceramic (ZrO₂), low-stiffness β-titanium alloy (β-Ti), and poly-ether-ether-ketone (PEEK) were evaluated during a clenching scenario. A systematic analysis was performed using statistical modeling to examine ten variations in bone quality, including cortical thickness and homogeneous bone stiffness. Additionally, two CT-based subject-specific comparisons were carried out using mandibles with distinctly different bone qualities. Implants made from materials with lower stiffness resulted in increased peri-implant strain and stress levels. In the statistical analysis, these effects were not significant when accounting for inter-individual variability of the bone qualities (p > 0.05). Cortical bone stiffness strongly correlated with peri-implant bone stress (r = 0.96 ± 0.01), while trabecular bone stiffness correlated with maximum (r = 0.71 ± 0.01) and minimum (r = -0.83 ± 0.02) principal strain in the bone. In the subject-specific analysis, stress and strain in the peri-implant bone increased for the low-quality bone and were significant for a PEEK-based implant (p < 0.001). Within the restrictions of the simplified numerical models and limited generalizability of the present findings, materials with lower stiffness may reduce peri-implant stress shielding but simultaneously increase stress at the bone-implant interface. However, their overall effect was not statistically significant when inter-individual variation in bone quality were considered.