Effect of bone loss on pullout behavior of shape memory alloy dental implant: finite element analysis and experimental study

Abstract

Abstract The purpose of this study is to examine the effect of bone loss around implant screws on the resistance of the screw connection to bone. This problem will be solved using the nonlinear finite element method in ABAQUS software. Loss of bone is caused by the formation of empty spherical cavities within the bone, which are randomly distributed throughout. Under the UMAT subroutine, the constitutive equations of shape memory alloy (SMA) materials will be introduced to the software. These equations will be employed to account for the superelastic behavior of the implant screws. An experimental study will be conducted in order to validate this finite element model. Direct tension tests are used in order to determine the experimental force-displacement curve of the implant pull-out. Finite element models will be evaluated by comparing experimental force-displacement curves with those generated by finite element models. Furthermore, the performance of titanium and shape memory implants is examined. Compared to a titanium implant, a shape memory implant causes an increase of approximately 130% in the displacement of the implant separation, which is a significant difference. Moreover, an additional 1% of cavities in the bone results in a 7% reduction in the pullout force and the adhesion between the implant and the bone. Additionally, a 200% increase in porosity results in a 20% decrease in cohesion force as a result of reduced bone density and crack points.