Accuracy Assessment of 3D-Printed Surgical Guides for Palatal Miniscrew Placement: A Retrospective Study

Background: The aim of this retrospective study was to conduct an in vivo evaluation of the accuracy of surgical guides obtained via 3D printing technology that were used to transfer the 3D software-planned position and axis during palatal miniscrew placement. Methods: Twenty-four Caucasian subjects with permanent dentition underwent a CBCT examination to plan palatal skeletal anchorage using two miniscrews in the anterior palatal arch. A specific software function capable of identifying and displaying all CBCT scans passing through the planned miniscrew axis was used to identify the scan showing the maximum discrepancy between the planned and final miniscrew placement. The maximum insertion angle discrepancy and the maximum linear difference between the head and tip of the miniscrew were measured on the overlaid 3D STL models of the planned miniscrew position at CBCT with the final clinical position of the miniscrew. Results: Descriptive and inferential statistics were performed. On average, there was a discrepancy between the planned insertion axis and the final insertion axis of 2.95◦ (SD ± 1.13◦ ), with a 10 mm miniscrew length. Conclusion: Three-dimensional I.-printed surgical guides for palatal miniscrew placement show a mean deviation of 2.95◦ from the planned position, indicating good but improvable accuracy in placement.