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. Likewise, the proximity of their follicles and crowns does not seem to affect the root structure of the lower incisors, producing minimal and infrequent root resorption. Key words: Mandibular canine impaction, incisor root morphometry, cone-beam CT.

The objectives of the treatment of impacted canines differ according to the characteristics of dental malocclusion. Traction of the tooth is a conservative and viable alternative, which allows for maintaining stability and occlusal function. The following case report describes the treatment of an 11.6-year-old female patient, who presented bilateral impaction of mandibular canines in contact with the midline, mixed dentition in the inter-transitional period, class I angle malocclusion, with light crowding teeth. The treatment comprised three phases. The first phase, verticalization of the mandibular canines in mixed dentition, was performed to pull the impacted bilateral mandibular canines towards the dental arch to achieve their verticalization, maintaining the molar relationship, and the position of the upper and lower incisors. In the second phase, osteogenic rest was planned to relieve post-traction stress while awaiting the replacement of the mixed dentition. Finally, the third phase in permanent dentition was to align and level canines within the arch after extraction of the deciduous canines. For the viability of the permanent mandibular canines in the dental arch, orthosurgical traction was implemented, with a traction system with closed nickel–titanium coil springs with a transitory rigid dental-mucous-supported anchorage device, which allowed control and protection of the adjacent teeth and movements with helical forces of a controlled three-dimensional range. The results of the treatment were adequate, achieving consolidated molar and canine relationships, overjet, overbite, and optimal facial balance.