KEY FACTORS FOR MINI-IMPLANT SUCCESS: THE CRITICAL ROLE OF CORTICAL BONE THICKNESS AND ORTHODONTIC FORCES IN ENHANCING STABILITY AND PREVENTING FAILURE

This study aims to analyze the biomechanical performance of titanium (Ti6Al4V) mini-implants (MIs) under orthodontic forces using finite element analysis (FEA) and to evaluate stress, strain, and displacement behavior within cortical and spongy bone under realistic clinical conditions.Materials and methods: A threedimensional finite element model of a mini-implant (2.0 mm diameter, 12 mm length) was developed using CT-based reconstruction of the mandible and periodontal ligament.The model was meshed with tetrahedral elements and simulated in ANSYS Workbench 19.2.Material properties for bones, teeth, ligament, and implant were defined as linear elastic, hom ogeneous, and isotropic.Orthodontic forces of 2N and 10N were applied at a 30 angle to re plicate molar intrusion scenarios.Stress, strain, and displacement distributions were analyzed for cortical and spongy bone, with special attention to localized areas of maximum impact.Results: Maximum von Mises stress and equivalent strain values were localized around the implant insertion site.Cortical and spongy bone demonstrated high resistance to applied forces, with stress and strain levels remaining below their fracture thresholds.The results highlighted the critical role of cortical bone thickness in ensuring prima ry stability.Displacement was minimal, with a maximum value of 0.028948 mm at the implant head under a 2N force, demonstrating functional stability.Forces exceeding 3N were identified as the threshold for potential spongy bone failure, reinforcing the appropriateness of 2N for orthodontic applications.Conclusions: The study confirms that mini-implants can effectively withstand orthodontic forces when inserted into adequate cortical bone thickness.The int egration of finite element modeling with clinical insights provides valuable guidance for optimizing mini-implant performance and minimizing adverse effects.These findings contri bute to improving treatment strategies and ensuring the longevity of orthodontic anchorage systems.