Milled surgical guides vs. freehand placement of orthodontic implants: a preclinical micro-CT study

Objective The present study evaluated the transfer accuracy of computer-aided designed and manufactured (CAD/CAM) milled guides compared with freehand placement of orthodontic temporary anchorage devices (TADs). Methods Sixty TADs were placed in 30 typodonts, using either CAD/CAM-milled guides or conventional freehand insertion. The freehand insertions were performed by one orthodontist and one oral surgeon. Micro-CT scans were obtained to determine actual TAD positions. Deviations from planned positions were assessed via vector analysis in vertical, horizontal, and transversal axes, as well as angular displacement. Linear mixed models with Items as random effects were applied to evaluate the influence of group and quadrant as fixed effects while accounting for repeated measures. Results Guided placement demonstrated significantly higher accuracy across almost all linear and angular dimensions compared with freehand insertion ( p < 0.01). Greater accuracy was shown for the oral surgeon compared with the orthodontist for freehand placement ( p < 0.01). Inter- and intra-observer agreement was excellent. Conclusion CAD/CAM milled guides significantly improved TAD placement accuracy compared with freehand insertion. This preclinical study supports their potential clinical benefit in single-session guided workflows, particularly for enhancing precision across different operator experience levels.