The Effect of Biomechanical Loading Parameters on Stress and Strain Behavior of Orthodontic Mini-Implants: A Finite Element Study

Background/Objectives: This study evaluated the influence of key biomechanical pa-rameters—orthodontic force magnitude, loading direction, and insertion depth—on stress and strain distribution in orthodontic mini-implants using three-dimensional fi-nite element analysis (FEM). Methods: A three-dimensional model of a titanium or-thodontic mini-implant inserted into a mandibular bone segment was developed and analyzed under varying force magnitudes (1–10 N), loading directions (30°, 45°, and 60°), and insertion depths (5–7 mm). Cortical and cancellous bone components were included, and static loading conditions were applied using simplified, linear elastic material assumptions. Results: Stress and strain levels increased with higher force magnitudes, with implant stresses approaching critical values at loads above 9 N. Cor-tical bone stresses remained within physiological limits, whereas cancellous bone ex-ceeded damage thresholds at forces greater than 3 N. A 60° loading direction reduced implant bending and strain, while deeper insertion significantly decreased strain and displacement, indicating improved primary stability. Conclusions: Optimal mechani-cal behavior occurred under 1–3 N forces, 60° loading direction, and 6–7 mm insertion depth. Loads above 9 N approached fatigue and interfacial risk. These findings align with prior experimental evidence and provide quantitative guidance for.