Investigation of structural stress distributions under chewing force of prosthetic restorations on teeth with apical lesions restored with different post materials by finite element analysis

Investigation of Structural Stress Distributions Under Chewing Force of Prosthetic Restorations on Teeth with Apical Lesions Restored with Different Post Materials by Finite Element Analysis Objective: The aim of this study was to investigate the stress against force in an abutment tooth with apical lesion restored with different post materials using finite element analysis. Method: Four different SEA models were fabricated to represent the tooth conditions underlying prosthetic restorations restored with different post materials: (a) healthy mandibular premolars, (b) root canal treated fiber post premolars with periapical lesions underlying a threemember bridge, (c) root canal treated cast post premolars with periapical lesions underlying a three-member bridge, (d) root canal treated zirconia post premolars with periapical lesions underlying a three-member bridge. The occlusal static load on each of the tooth models was applied at a value of 300 N at a 45° angle parallel to the long axis of the tooth at the lingual inclination of the buccal apex of the tooth. These models were created by SEA method using Solidworks 3D CAD model. ANSYS Workbench program (ANSYS, Canonsburg, USA) interface was used for structural analysis. The existing mandibular premolar tooth was created with supporting tissues in accordance with the average anatomical dimensions of the periodontal ligament and alveolar bone, taking into account the literature data. The models used gutta-percha as the root canal filling material. All crowns were cemented with dual cure resin cement. Results: It was observed that the stresses caused by occlusal load application were concentrated in similar regions in all models (force applied pulley, buccal collar, root cervical and middle triad), and in the bridge prosthesis models, unlike the healthy tooth model, they were also concentrated in the binding regions. Conclusion: In the models with different post materials and bridge abutments, it was observed that the models with high elastic modulus (Model 3, Model 4) retained the stresses in the post structure and transmitted less stress to the surrounding dentin tissue, while the model with low modulus of elasticity (Model 2) did not retain the stresses in the post structure and transmitted them to the surrounding dentin tissue. Keywords: Lesioned tooth, fiber post, cast post, cast post, zirconia post, metal supported porcelain, bridge, finite element analysis