Evaluation of masseter, temporal and lateral pterygoid muscle botox and stress on the temporomandibular joint with bite plate use in patients with bruxism by three-dimensional finite element analysis

Aim: The aim of this study is to compare the stress changes that will occur in the temporomandibular joint of the use of botox to the masseter, temporal, and lateral pterygoid muscles in patients with bruxism, using 3D finite element analysis. Materials and Methods: A 3-dimensional jaw model was created using tomography data from an adult patient with bruxism. Bone .stl model was obtained from tomography data in 3DSlicer software. Reverse engineering and three-dimensional CAD activities were carried out with ANSYS Spaceclaim software, adapting solid models to the analysis environment and creating optimized mesh activities were carried out with ANSYS Workbench software; LS-DYNA solver was used to solve the finite element models created. Seven different loading scenarios of botox application and bite plate use were created on three main models in which the temporomandibular joint was displaced unilaterally and bilaterally anteriorly, within the normal condyle-disc-fossa relationship. Von Mises stress distributions in the masticatory muscles, articular fossa of the TMJ, mandibular condyle and joint disc during clenching of the teeth were examined in all three main models. Results: In the non-displacement models, the stresses were mostly concentrated in the middle region of the condyle and disc, in the posteromedial of the glenoid fossa. A reduction in the stress observed in the condylar disc and glenoid fossa was observed with the use of Botox and bite plate. The combined application of masseter-temporal botox with the use of bite plate in the models was much more effective in reducing the stresses on the condyle-disc-fossa than the application of botox to the masseter-temporal-lateral pterygoid muscles. Conclusion: Due to the anatomical difficulty of botox application to the lateral pterygoid muscle, the complications of blind injection due to the difficulty of unguided intramuscular injection, the primary treatment option for bruxism with and without displacement may be the use of a bite plate with botox injection into the masseter and temporal muscles, which gives better results in reducing intra-articular stress. Keywords: Bruxism, Botox, Bite Plate, Finite Element Analysis