Three-dimensional evaluation of mandibular canine impaction characteristics and their relationship with lower incisor root morphometry

Background: To three-dimensionally evaluate the characteristics of mandibular canine impaction with the morphometry of the roots of the lower incisors. Material and Methods: Cone-beam computed tomography (CBCT) scans of 35 individuals (18 males and 17 females) with a mean age of 14.37± 10.26 years were evaluated. Forty-three impacted mandibular canines (IMbC) were evaluated. Their location, sector and level of impaction were determined. Likewise, the distances of the canines to the occlusal plane, the angulations with respect to the midline and adjacent lateral incisors, the length of the impacted canines, and of the lower incisors were measured. Finally, the presence of incisor root resorption was determined. Chi-square and Kruskal Wallis tests were employed (P<0.05). Results: The buccal position of the IMbCs was the most predominant (65.1%), and the location below the apical middle third of the lower incisor root was the most frequent (32.6%). No statistical significance was found between root resorption and location, level and impaction sector. Only mild root resorption and impaction sector 5 was significant (66.70%; P<0.001). The proximity of the follicle and crown of the IMbC did not affect the root structure of the lower incisors. 72.1% and 52.2% of mandibular canines did not present contact of the impacted canine or its follicle with the adjacent tooth respectively. Root lengths were similar in the different types of impactions (P>0.05). Conclusions: IMbCs are mostly positioned buccally and below the apical middle third of the root of the lower incisors.