Impact of considering bone remodelling in risk assessment of mandibular implant-supported bridges

Efforts have been made to improve the prediction of implant treatment outcomes through biomechanical analyses using finite-element (FE) analysis. Particularly, a bone remodelling numerical model has been recently applied to forecast long-term stability. However, there is a scarcity of research on the long-term biomechanical stability of implant-supported bridges. This study investigates the impact of integrating a bone remodelling numerical model into FE analysis to evaluate the biomechanical stability of mandibular implant-supported bridges. To evaluate the impact of integrated bone remodelling, FE analyses were performed with and without a bone remodelling model. The bone remodelling model was implemented in Abaqus as a user subroutine, UMAT, used to define a mechanical behaviour of material. Cases were compared based on the number of fixtures used in the implant-supported bridges and the initial bone quality to assess risks in different treatment scenarios. The peri-implant bone density distribution ultimately showed higher values than the initial value after bone remodelling. The study analysed differences in microstrain proportions within the peri-implant bone, with and without bone remodelling, following simulated masticatory activity. Absence of bone remodelling consideration results in elevated microstrain, especially among elderly patients with fewer implants and in the second molar position. This omission leads to an overestimation of differences in high microstrain proportion based on implant position (senior, Group 1: 18.91%p) and number of implants (senior, second molar: 13.8%p). Initial bone quality has a significant influence on bone remodelling. The absence of long-term analysis exaggerates the risks for all considered cases. This study emphasizes the importance of incorporating bone remodelling considerations into the stability analysis of implant-supported bridges, particularly when they are used with fewer implants and for elderly patients.