Three-dimensional evaluation of root dimensions and alveolar ridge width of maxillary lateral incisors in patients with unilateral agenesis

BACKGROUND The objective of this retrospective case-control study was to measure the maxillary lateral incisor root dimensions and quantify the labial and palatal bone in patients with unilateral maxillary lateral incisor agenesis (MLIA) after orthodontic treatment and compare them to non-agenesis controls using cone beam computed tomography. METHODS The labiopalatal and mesiodistal root dimensions, mesiodistal coronal dimensions, and labiopalatal bone and alveolar ridge widths of the maxillary lateral incisor were assessed on posttreatment cone beam computed tomography scans of 15 patients (mean age 16.5 ± 3.4 years, 9 females and 6 males) with maxillary lateral incisor agenesis and 15 gender-matched patients (mean age 16.08 ± 3.23 years) with no dental agenesis or anterior Bolton discrepancy. The Mann-Whitney test was used to distinguish any differences in root width, crown width, or changes in labial or palatal bone width between the two groups. RESULTS The median labiopalatal root width was narrower in the MLIA group at the level of the cementoenamel junction (CEJ) to 8 mm apical of the CEJ compared to controls (p ≤ 0.009). The mesiodistal root width was significantly reduced in the MLIA group at the CEJ and at 4 mm apical to the CEJ. The labiopalatal alveolar ridge width was significantly decreased at 2 mm apical to the CEJ in MLIA group. The mesiodistal crown width was significantly smaller in the MLIA group at both the incisal edge and at the crown midpoint. The bone thickness was similar in both groups. CONCLUSIONS Coronal and root dimensions in patients with MLIA were reduced compared to controls. Alveolar ridge width was also reduced in patients with MLIA, although bone thickness was not different than controls.