3D Printed Guides and Finite Element Analysis in Dental Autotransplantation: Biomechanical Efficiency and Clinical Workflow Optimization

BACKGROUND: This study evaluates novel osteotomy guides, a morphology-adapted custom drill, and root-immersion containers to enhance the precision in dental autotransplantation through in vitro experiments and finite element analysis (FEA). METHODS: About 30 mandibular Cone Beam Computed Tomography (CBCT) datasets were reconstructed to design reverse-engineered osteotomy guides and a steel custom drill based on root morphology statistics. About 90 3D-printed models (30 cases × 3 groups: guide-assisted, custom drill, and freehand) underwent socket preparation, with operative time and cavity dimensions quantified via optical scanning. Extracorporeal root canal treatment compared between teeth in root-immersion containers (n=30) and handheld teeth (n=30). FEA simulated flexible/rigid fixation to assess the apical stress and displacement. RESULTS: (1) Osteotomy time was shortest with the custom drill (3.70 ± 0.42 min), followed by guided (5.33 ± 0.35 min) and freehand (12.18 ± 0.98 min; p < 0.001). (2) Root-socket distances were 0.58 ± 0.10 mm (custom drill) and 0.94 ± 0.12 mm (guided), outperforming freehand (1.75 ± 0.19 mm; p < 0.001). (3) Root canal duration was comparable between container (13.77 ± 0.78 min) and handheld (13.89 ± 1.12 min; p > 0.05), but procedural consistency favored the container (p < 0.001). (4) Rigid splinting reduced apical stress and limited displacement to 1.2 mm versus 3-5 mm with flexible methods. CONCLUSION: The custom drill achieved efficient socket preparation with superior root adaptation, while the root-immersion container standardized therapy quality. Rigid fixation minimized biomechanical risks, collectively ensuring predictable autotransplantation outcomes.