Evaluation of the effect of periapical lesion diameter on stress distribution under tooth loading in canal-treated upper central incisors restored with fiber post by finite element analysis

Objective: In this study, it was aimed to investigate the structural stress distribution under static load by using finite element analysis (FEA) method in teeth restored with fiber post due to material loss and with periapical lesions of various sizes. Method: The sample models were simulated using the Solidworks 3D CAD model to apply the SEA method. ANSYS Workbench program (ANSYS, Canonsburg, USA) interface was used for structural analysis. Upper central incisor reference model without periapical lesions restored with glass fiber post (ParaPost Fiber White, Coltène/Whaledent, Mahwah, USA) and all-ceramic crown (IPS Empress, Ivoclar Vivadent, Schaan, Liechtenstein) and total of 5 models were analyzed, including models representing the periapical lesion with 2-, 4-,, 6- to 8 mm diameters. The analysis setups were prepared in accordance with the scientific literature, at an angle of 135° to the long axis of the tooth, to simulate the deformation behavior of the models in the most realistic way under 300 N loading conditions. Results: Equivalent stress values were calculated according to the Von Mises hypothesis, and stress distributions in the models were evaluated. It has been observed that the stress resulting from the application of load in all models is concentrated in similar regions on the models. However; It was observed that the intense stress area formed in the buccal middle third of the root was moved to the coronal side of the tooth with the increasing lesion diameter from the lesionless tooth. The region where the maximum equivalent stress occurs is the buccal region of the neck of the tooth in all models; values were found close to each other. The lesion sites in all models with a periapical lesion were areas where low stresses were observed. Conclusion: It has been confirmed that the presence and size of the periapical lesion in the teeth have an effect on the stress distribution in the different components of the tooth. Keywords: Periapical lesion, fiber post, finite element analysis