Effect of Treatment Model on Biomechanical Behaviour of Maxillary Incisors with External Cervical Resorption at Different Progression Levels

Objectives: The aim was to evaluate the biomechanical behaviour of maxillary incisors with external cervical resorption at different progression levels after receiving different treatment options under occlusal forces using finite element analysis. Materials and Methods A 3D model of an intact maxillary incisor was constructed and then modified to have external resorption (ECR)cavities with different progression levels in buccal cervical area. Models with ECR cavities confined to dentine repaired using either with Biodentine, composite resine or GIC were generated. Models with ECR cavities with pulp invasion requiring direct pulp capping were simulated as repaired using Biodentine only or 1 mm thick Biodentine and either composite resin or GIC for the rest of the cavity. Also models with root canal treatment and ECR defect repaired using either with Biodentine, composite resine or GIC were generated. A force of 240 N was applied from incisal edge. Principal stresses in dentine were evaluated. Results GIC showed more favorable results compared to other materials in ECR cavities confined to dentine. The use of solely Biodentine presented more favorable Pmin stresses compared to other materials in ECR cavities with close pulp proximity. Exceptionally, the models localized in coronal third of the root with circumferential extension of the cavity more than 90° showed more favourable results for GIC. The presence of root canal treatment had no prominent effect on stresses values. Conclusions The use of GIC in ECR lesions confined to dentine is recommended. However, Biodentine may be a better option for the restoration of ECR lesions that are close to pulp with/without root canal treatment. Except when the circumferential extension of the cavity is more than 90°, the use of GIC can be more advantageous.