From Virtual Surgical Planning to Clinical Accuracy: A Proof-of-Principle Study of 3D- Printed Patient-Specific Drill and Placement Guides for Surgically Assisted Rapid Palatal Expansion

Abstract Purpose Surgically assisted rapid palatal expansion (SARPE) requires accurate positioning of the distraction device to achieve controlled skeletal expansion while limiting dentoalveolar side effects. Conventional workflows remain technique-sensitive and depend largely on intraoperative judgement. This proof-of-principle study investigated the technical feasibility of a fully digital workflow integrating virtual surgical planning (VSP) with patient-specific drill and placement guides for a customized SARPE device and quantified the accuracy of transferring the planned device position to surgery in a single patient. Methods VSP included device positioning and screw trajectory planning. Patient-specific drill guide and patient-specific placement guide were designed as dentition-supported, one-fit-only devices and additively manufactured. A hybrid patient-specific SARPE device was positioned using these guides. Transfer accuracy was evaluated by surface-based superimposition of the planned device geometry and its postoperative position and quantified. Results Superimposition demonstrated close correspondence in the central palatal region containing the expansion screw, whereas the largest deviations occurred at the lateral fixation arms. Dice similarity coefficient was 0.17, the mean model-to-model surface distance was 2.78 mm, mean Hausdorff distance was 1.00 mm and maximum Hausdorff distance 5.70 mm. Conclusions This fully digital workflow was technically feasible and successfully implemented. Although transfer appeared most accurate in the functionally decisive central region, peripheral deviations and limited global overlap preclude interpreting this single case as evidence of established accuracy. Cohort studies with predefined regional accuracy endpoints are needed to determine reproducibility, identify sources of error and assess whether the workflow provides clinically meaningful benefits over conventional SARPE device positioning.