Finite Element Analysis of Stress Distribution in Immature Permanent Incisors Following MTA Apexification with Different Coronal Base Materials.

BACKGROUND/AIM: Immature permanent teeth with necrotic pulps present thin dentinal walls and open apices, making them highly susceptible to cervical fractures even after apexification. This study aimed to compare stress distribution patterns produced by different coronal base materials following mineral trioxide aggregate (MTA) apexification using three-dimensional finite element analysis (FEA). MATERIALS AND METHODS: A CBCT-based model of a maxillary immature incisor was reconstructed and modified to simulate six restorative scenarios: control (sound tooth), MTA + conventional glass ionomer cement (GIC), MTA + resin-modified glass ionomer cement (RMGIC), MTA + bulk-fill flowable composite, MTA + conventional composite resin, and MTA + flowable composite resin. A 100 N oblique load (45°) was applied, and von Mises stress, displacement, and periodontal ligament strain were analyzed. Inter-model comparisons were performed using one-way ANOVA with Tukey post hoc tests (p < 0.05). RESULTS: All models exhibited maximum stress concentration in the cervical third of the root. Bulk-fill flowable composite and RMGIC generated lower cervical stress and more homogeneous distribution compared with GIC or conventional composite resin. Conventional composite resin produced the highest stress concentration due to its higher stiffness. Derived biomechanical metrics confirmed statistically significant differences between groups (p < 0.05). CONCLUSIONS: The coronal base material strongly affects the biomechanical behavior of immature incisors restored after MTA apexification. Selecting low-modulus, stress-dissipating materials such as bulk-fill flowable composites or RMGICs may minimize cervical stress and potentially reduce fracture risk. These computational findings warrant validation through in vitro and clinical studies.