[Evaluation of rapid teeth movement through reducing resistance and distraction in Beagle dogs with cone-beam...

To evaluate the effect of rapid teeth movement through reducing resistance and distraction using cone-beam computed tomography (CBCT).

The left or right side of the mandible of 10 beagles (5 males and 5 females) was randomly selected as the control side (for the conventional distraction with a force of about 85 g) and the other side as the experimental side (subjected to reducing resistance and distraction). CBCT images were taken at 5, 10, and 15 days and also after retaining for 10 and 90 days after distraction for 15 days. The distance of teeth transportation, degree of inclination, alveolar bone density of the compressive area and root resorption were evaluated based on the CBCT images and Ez3D2009 visualization software.

No significant difference was found between CBCT-based measurement and direct measurement of teeth transportation distance within the mouths (P>0.05). Teeth inclination on the experimental side was slightly greater than that on the control side (P<0.05). The root resorption on the experimental side was minimal, and the bone density increased gradually along with the teeth migration. The experimental side showed a comparable newly formed alveolar bone density and similar X-ray features of the compressive area with the control side.

CBCT three-dimensional imaging can resolve the problems of overlapping and deformation of the two-dimensional images and is especially useful for measurement of teeth inclination and alveolar bone density in the process of reducing resistance and distraction.