فهرست نشریات علمی دسترسی آزاد ایران

Background and objectives: Correct application of the Finite Element Method (FEM) can simulate tooth displacement and stress distribution in the periodontium under external forces and offer the correct prediction and appropriate therapeutical choices. The present study analyzed the alveolar bone's mechanical behavior under typical intrusion or oblique forces for several levels of reduced periodontium using a dynamic linear/ nonlinear simulation. Materials and methods: This study's modeling, meshing, simulation, and finite element analysis were carried out using SolidWorks software (2021, SP2, Dassault Systèmes). The mandibular and maxillary canines were modeled using cone beam computed tomography images. Teeth, lamina dura and cortical and cancellous bones were considered linear isotropic material, whereas the periodontal membrane was considered a hyper- elastic first-order Ogden material to account for its flexibility. Crown- to- root ratio (C/R) of 0.8, 1.25, 2 and 3.5 was simulated. All simulations were dynamic nonlinear/ linear to account for the natural displacements in the periodontium under occlusal forces. The teeth were submitted to intrusion or oblique (15 and 45 degrees) 100 Newton to simulate typical occlusal forces. Results: The maximum von Mises stress and maximum equivalent strain for all models increase with bone loss. Furthermore, the rate at which these factors increase from each bone loss step to the following increases noticeably after 6 mm of bone loss. The amount and rate of increase in the maximum stress and stress experienced by alveolar bone are higher for forces with higher degrees of deviation from the tooth axis. The maximum stress and strain for the intrusion, 15-degree and 45-degree models were 137Mpa/ 0.006, 268Mpa/ 0.013 and 800Mpa/ 0.040, respectively (All at C/R = 3.5). Conclusion: Reduction of alveolar bone level (increased crown- to- root ratio) leads to higher levels of stress and strain, which show a steep rise at the 6 mm of bone loss. This observation leads our attention toward tooth-specific occlusal consideration in patients with reduced periodontium.