This systematic review aimed to assess whether the initial apical position of impacted maxillary canines, evaluated using cone-beam computed tomography CBCT, influences three-dimensional root displacement during orthodontic traction. An extensive literature search was conducted in PubMed/MEDLINE, Web of Science, Embase, Scopus, and the Cochrane Library up to November 2025. Prospective and retrospective clinical studies including pre-treatment CBCT assessment and reporting either direct apical displacement or CBCT-derived three-dimensional position parameters were considered eligible. Study selection, data extraction, and quality appraisal were carried out independently by two reviewers. Seven studies met the inclusion criteria. Substantial heterogeneity was observed in imaging protocols, reference systems, traction mechanics, and outcome measures, precluding quantitative synthesis. Only two studies directly quantified three-dimensional apical displacement using CBCT–CBCT or CBCT–STL superimposition methods, predominantly suggesting bodily movement patterns; although, this is based on limited direct evidence, with velocities ranging from 0.29 to 0.84 mm/month. The remaining studies provided indirect evidence based on angular changes, positional parameters, or traction duration. Taken together, the available evidence suggests that unfavorable initial apical positions, including palatal or bicortical impactions and increased root angulation, may be associated with greater biomechanical complexity and longer traction duration. Although CBCT-based three-dimensional evaluation provides clinically relevant diagnostic information, standardized measurement protocols are required to improve comparability and reproducibility across studies.
García et al. (Sat,) studied this question.