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

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).

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.

(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.

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.