Three-dimensional assessment of alveolar bone changes and root resorption in extraction patients after fixed orthodontic treatment: A prospective study.

Background: The aim of this study was to evaluate the alveolar crestal bone height, alveolar bone thickness, and root resorption in mandibular incisors after fixed orthodontic treatment.

Methods: A total of 35 patients (mean age 17.02 ± 3.24 years) with moderate to severe mandibular anterior crowding requiring first premolar extraction were included. Cone beam computed tomography scans of the mandibular anterior region were obtained from the patients before and after orthodontic treatment. The alveolar crestal bone height, cortical bone thickness (CBT) (at apex and midroot level), labial and lingual alveolar bone thickness, and root resorption were assessed for all mandibular incisors. Paired Student's t test was used to compare pretreatment and post-treatment alveolar bone changes and root resorption.

Results: A significant decrease in lingual crestal bone height was observed in all mandibular incisors after orthodontic treatment (P < 0.001). Lingual CBT decreased at the midroot level significantly for all mandibular incisors after completion of orthodontic treatment (P < 0.001). A significant decrease in total lingual bone thickness was observed in all mandibular incisors (P < 0.001). Root lengths of mandibular incisors decreased significantly in the sagittal and coronal sections after orthodontic treatment (P < 0.001).

Conclusions: Fixed orthodontic treatment with premolar extraction results in a significant reduction of alveolar crestal bone height, CBT (at midroot level), and alveolar bone thickness on the lingual aspect of mandibular incisors. Significant orthodontically induced inflammatory root resorption was observed in all mandibular incisors after orthodontic treatment.