3D finite element assessment of insertion angle influence on mini screw stress distribution and its clinical implications: A Systematic review

To systematically review 3D finite element analysis (FEA) studies assessing how orthodontic miniscrew insertion angle impacts stress distribution in surrounding bone. Fourteen in vitro 3D‑FEA studies up to June 2025 were identified through searches of PubMed, Cochrane Library, Semantic Scholar, and Google Scholar. Inclusion criteria required comparison of stress around miniscrews inserted at different angles. Two independent reviewers screened articles and extracted data via a predesigned form. A customized risk-of-bias tool-evaluating mesh quality, material properties, boundary conditions, and loading protocols-was applied. The majority of included studies indicated that miniscrews inserted at 90° relative to cortical bone exhibited lower stress concentrations at the implant-bone interface compared to oblique angles (30°-60°). Oblique insertion was associated with elevated cortical stress and increased displacement risk. Stress distribution was more favorable in the maxilla than in the mandible, likely due to cortical thickness differences. Within the limitations of computational modeling, perpendicular (90°) insertion of orthodontic miniscrews offers biomechanical advantages by reducing peri‑implant stress. Clinicians should consider this insertion angle to enhance primary stability and minimize miniscrew failure.