Clinical evaluation of 3D-printed templates for accurate and safe mini-screw implantation

Objectives: To develop mini-screw templates using three-dimensional (3D) printing technology to prevent root damage during implantation, and to evaluate the accuracy and safety of the implantation process. Methods: Thirteen patients requiring mini-screw implantation between the maxillary second premolar and first molar were recruited for this study. A total of 21 mini-screws were placed in vivo using patient-specific mini-screw templates designed with manipulation software. Following implantation, cone-beam computed tomography (CBCT) scans were obtained. The postoperative CBCT data were superimposed onto the preoperative scans using a correntropy-based registration algorithm to assess implant positioning. The accuracy and safety of mini-screw placement under the guidance of the 3D-printed templates were subsequently evaluated. Results: The mean 3D deviation at the mini-screw tail was 1.10 ± 0.48 mm. The deviations in the coronal, sagittal, and vertical directions were 0.31 ± 0.28 mm, 0.38 ± 0.29 mm, and 0.88 ± 0.51 mm, respectively. The actual deviation (0.39 ± 0.30 mm) was significantly smaller than the permitted deviation (1.04 ± 0.45 mm), with the difference reaching statistical significance (P < 0.05). Conclusions: The 3D-printed mini-screw templates demonstrated high accuracy and safety in guiding mini-screw implantation between the maxillary second premolar and first molar. The actual deviations observed were significantly smaller than the clinically accepted limits, indicating reliable positional control and minimized risk of root damage. Clinical significance: 3D-printed templates significantly enhance the precision and predictability of orthodontic mini-screw placement and provide a clinically reliable technique.