Impacted maxillary canines and their relationship with lateral incisor resorption: a cone beam computed tomography (CBCT) study

Objective The spatial position of a canine can affect the level of proximal root resorption and the success of orthodontic treatment. The aim of this study was to examine the mesiodistal and vertical position of impacted maxillary canines and to assess their relationship with the lateral incisor by using cone beam computed tomography (CBCT). Material and method One hundred and sixty-nine CBCT scans of patients presenting with maxillary impacted canines were included in the study. The buccopalatal, mesiodistal (classified as sectors I, II, III, IV from distal to mesial) and vertical (cervical, middle, apical) position of the maxillary impacted canines were determined. The positional effect on the morphology (width, length, and depth) and resorption was assessed on the roots of the maxillary lateral incisors. Obtained data were statistically analysed by using Student t-test, the Mann Whitney U and Chi-Square tests. Results Of the maxillary impacted canines, the 34.72% that had associated resorption on the adjacent lateral incisors were buccally positioned, and 65.28% were palatally positioned. While 45.58% of sector I impacted maxillary canines were buccally positioned, 68.31% of sector IV impacted maxillary canines were palatally positioned. Furthermore, there was a statistical significance between the mesiodistal position and palatal or buccal maxillary canine impaction (p < 0.05). In addition, the vertical position of the impacted maxillary canines was also related to their mesiodistal and buccopalatal positions (p < 0.05). Conclusion While all maxillary impacted canines had the potential to cause lateral incisor resorption, there was no close relationship related to the canine’s buccopalatal, mesiodistal and vertical position. Nevertheless, if an impacted maxillary canine migrated towards the midline, the buccopalatal and vertical position of the tooth changed from buccal to palatal and cervical to apical, respectively.