Eruptive path of maxillary canines in patients with lateral incisor agenesis: a longitudinal follow-up.

Objectives: To evaluate the eruptive angle, mesiodistal position and height of permanent maxillary canines in patients with agenesis of the permanent maxillary lateral incisor (AL) from the mixed to the permanent dentition.

Materials and methods: The sample was composed of orthodontic records of subjects with and without AL. The agenesis group comprised 11 patients, 7 with bilateral and 4 with unilateral AL (8.6 ± 1.6 years, 4 males, 7 females). The control group comprised 9 patients (8.5 ± 1.0 years, 2 males, 7 females) without AL. Panoramic radiographs were analyzed at three timepoints: inter-transitional period (T1), second transitional period (10.1±0.9 years, T2) and permanent dentition (11.9±1.1 years, T3). The long axis angle of the permanent maxillary canine (α and β), the mesiodistal distance (d) in relation to the central incisor, and the height (H) from the cusp tip of the canine to the occlusal plane were evaluated. Intergroup comparisons were performed with t-tests, Mann-Whitney, and Chi-square tests (P < 0.05).

Results: A mesial position of the canine cusp tip relative to the distal of the permanent maxillary central incisor was observed for the agenesis group at T1, T2 and T3. From T1 to T2, the agenesis group showed greater occlusal displacement of the canine tooth germ.

Conclusions: In patients with AL, canine tooth germs showed more mesial displacement and erupted a mean of 4.5 mm closer to the maxillary central incisors. Eruption of maxillary canines tended to be accelerated during the late mixed dentition in patients with AL.