Orthodontic treatment changes in bone mineral density distribution of maxillary alveolar bone in adolescent patients

Objectives: To examine whether clinical cone-beam computed tomography (CBCT) images can be used to assess three-dimensional bone mineral density (BMD) distribution changes in the alveolar bone (AB), reflecting the biological outcomes of orthodontic treatment in adolescent patients. Materials and Methods: CBCT images of 40 patients (28 females and 12 males; initial mean age = 14.42 ± 1.34 years, range, 11.9-17 years) taken before and after orthodontic treatment with full fixed appliances (treatment duration = 20.50 ± 4.03 months) were collected retrospectively. The AB at maxillary first molar locations (FDI 16 and 26) was digitally isolated using imaging software. A frequency plot of gray values proportional to BMD was developed for each AB region. The mean as well as the fifth percentile low and high gray values (low5 and high5) were computed. Changes in AB morphological parameters and cervical vertebral gray values of the same patient were also compared. A paired test was used to compare the parameters before and after orthodontic treatment. Results: The gray values of the AB and cervical vertebrae significantly increased after orthodontic treatment (P < .02). Changes in AB parameters before and after orthodontic treatment showed significant but weak positive linear relationships with changes in cervical vertebral parameters (0.12 < r2 < 0.48, P < .04). Conclusions: Rapid growth and bone mineralization in adolescent patients partially contribute to increased AB BMD following orthodontic treatment. These findings provide baseline information for planning orthodontic treatment specific to adolescents.