Morphometric evaluation of the alveolar bone around central incisors during surgical orthodontic treatment of high-angle skeletal class III malocclusion.

Abstract

To evaluate morphometric characteristics of alveolar bone around the incisors of high-angle skeletal class III patients receiving surgical orthodontic treatment. Thirty high-angle skeletal class III patients (mean age, 20.94±3.25years) underwent cone-beam computed tomography before treatment (T0), after pre-surgical orthodontic treatment (T1) and after treatment (T2). The vertical bone level (VBL), alveolar bone thickness (ABT), alveolar bone area (ABA) and position of upper and lower central incisors (UCIs and LCIs) were evaluated. The ABT included five levels (4, 6, 8mm from the cemento-enamel junction, midroot and root apex level). One-way repeated measures ANOVA with Bonferroni's multiple-comparison test and matched t test was performed to compare variables. Before treatment, the average labial ABT was approximately 1mm in UCIs and 0.38~0.79mm in LCIs, and the VBL of the LCIs was over 2mm. After treatment, the VBL increased by 2.19±1.96mm (P<.001) on the lingual side of UCIs and 2.78±2.29mm and 3.09±2.52mm on the labial and lingual sides of LCIs, respectively (all P<.001). ABT at every level decreased significantly, decreasing by 1.66±1.93mm at the 8mm level of UCIs and 1.06±1.01mm at the apex of LCIs (P<.001). The lingual ABA of UCIs and LCIs decreased by over 50% (P<.001). In high-angle skeletal class III patients, the condition of alveolar bone around UCIs and LCIs was extremely poor before treatment. Further alveolar bone resorption occurred during surgical orthodontic treatment. More attention should be paid to the movement of anterior teeth in cases of severe alveolar bone loss.