Biomechanical Effect of Different Biodentine Placement Levels in Regenerative Endodontic Procedures: A Finite Element Analysis and Fracture Resistance Study.

INTRODUCTION: The placement level of hydraulic calcium silicate (HCS) materials during regenerative endodontic procedures (REPs) may affect biomechanical performance of immature permanent teeth. This study aimed to evaluate effect of different Biodentine placement levels on biomechanical performance of immature permanent teeth treated with REPs using three-dimensional finite element analysis (FEA) validated by fracture resistance testing. METHODS: Standardized immature maxillary premolars (n = 10/group) were assigned to five groups: intact teeth (negative control), access preparation without restoration (positive control), and Biodentine placed above, at, or below the cementoenamel junction (CEJ), followed by adhesive restoration. The FEA was performed to evaluate stress distribution under occlusal loading. Fracture resistance and fracture patterns were assessed by compressive loading to failure. Data were analyzed groups using one-way ANOVA. RESULTS: Buccal cervical region exhibited highest stress concentration in all FEA models and corresponded to predominant fracture site during mechanical testing. Fracture resistance was the highest in intact teeth (1893.23 ± 63.30 N), followed by Biodentine placed below CEJ (1785.06 ± 69.11 N), at CEJ (1426.87 ± 96.09 N), above CEJ (946.61 ± 131.20 N), and positive control (724.48 ± 89.29 N). Biodentine placement below CEJ showed fracture resistance comparable to intact teeth and fewer non-restorable fractures (50%) than placement above the CEJ (70%) and positive control (80%). CONCLUSIONS: Biodentine placement level significantly influenced biomechanical performance of immature teeth treated with REPs. Placement below CEJ provided most favorable biomechanical performance by reducing cervical stress concentration, maintaining fracture resistance comparable to intact teeth, and decreasing non-restorable fractures.