How does the rate of dentoalveolar distraction affect the bone regenerate produced?

Introduction: This experimental study was designed to evaluate how the rate of dentoalveolar distraction into a bony defect affects bone quality and quantity. Methods: Using 6 adult foxhound dogs and a randomized split-mouth design, we evaluated the differences between regenerate bone produced by distracting segments of bone containing the second premolars at either 1 or 2 mm per day for 5 days, followed by a 6-week consolidation period. Microcomputed tomography was used to evaluate bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. Results: The lingual aspect of the regenerate exhibited more bone than did the buccal aspect, and all but one of the 12 specimens showed less than 1 mm of vertical bone deficiency in the regenerate area. No differences were found between the 1-mm per day and the 2-mm per day rates for bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. With the exception of trabecular separation on the 2-mm per day side (P = 0.030), there were no statistically significant differences between the mesial, middle, and distal segments of the regenerate. Compared with control bone, the regenerate bone was less dense, and had less bone volume, a higher trabecular number, and approximately half the trabecular thickness. Conclusions: Bone regenerate produced by rates of 1 and 2 mm per day of dentoalveolar distraction was similar in quality and quantity. Although less mature, the size and shape of the regenerate bone produced by rapid dentoalveolar distraction was comparable with the control bone.