Autonomous robotic execution of nonlinear toolpaths for geometry-matched osteotomy in tooth autotransplantation: an in vitro study

Tooth autotransplantation requires recipient socket preparation that matches donor root morphology while preserving surrounding bone. We developed an autonomous multi-axis robotic system that executes nonlinear, surface-conforming milling trajectories to create a geometry-matched socket and compared it with a static tooth-supported guide in forty 3D-printed mandibular models representing single-rooted and double-rooted anatomies. Recipient sockets were planned by offsetting the donor root surface by 0.5 mm and eliminating insertion axis undercuts. The robot executed the planned milling path with a depth-stop Lindemann bur, whereas the guide workflow used guided pilot drilling followed by freehand refinement. Robot assistance reduced deep positional errors and improved agreement between planned and prepared socket geometry, with the most pronounced benefit in double-rooted models, while overall preparation time was comparable between approaches. These findings support further clinical validation to confirm that autonomous robotic, surface-conforming osteotomy can improve full-depth geometric fidelity and reduce unnecessary bone removal in technique-sensitive autotransplantation procedures.