Effects of orthodontic treatment on human alveolar bone density distribution

The objective of this study was to examine if non-invasive clinical cone beam computed tomography (CBCT)-based degree of bone mineralization (DBM) measurement can be used to detect the different results from orthodontic treatment between the maxilla and mandible in human patients.

CBCT images were taken before and after orthodontic treatment from 43 patients (19 males and 24 females, 14.36 ± 1.50 years). A histogram of computed tomography (CT) attenuation value, which is equivalent to the DBM, was obtained from the alveolar cortical (AC), trabecular (AT), and enamel (E) regions of each image. Mean, standard deviation (SD), and coefficient of variation (COV) of the CT attenuation values were computed. The regional variations and percentage (%) differences between the E and alveolar regions of the CT attenuation parameters at the maxilla and mandible were analyzed before and after orthodontic treatment.

The AC had higher mean and variability (SD and COV) than the AT before and after treatment (p < 0.001). The variability was higher in the mandibular AC than in the maxillar AC (p < 0.01) independent of orthodontic treatment. The percentage (%) difference of variability of CT attenuation values changed for both AT and AC in the maxilla after orthodontic treatment, while that changed for only the AT (p < 0.02), but not for AC, in the mandible (p > 0.16).

The alveolar cortical region of the mandible responded differently to orthodontic treatment compared with other alveolar regions.

The CBCT-based DBM analysis can be used clinically to assess alveolar bone quality changes induced by orthodontic treatment to improve treatment planning and result evaluation.