Experimental tooth movement through mature and immature bone regenerates after distraction osteogenesis in dogs

The purpose of this study was to verify the influence of tooth movement on tooth roots and periodontal tissues when teeth were moved into mature, well-organized, and mineralized regenerate bone created after distraction osteogenesis compared with immature, fibrous, and less-mineralized bone. Six 15-month-old male beagles underwent 10 mm of bilateral mandibular distraction osteogenesis. After 2-week (group 1) and 12-week (group 2) consolidation periods, third premolars were moved distally into the regenerate bone with 100 g of orthodontic force for 12 weeks. Simultaneously, second premolars were also moved distally as controls. After completion of tooth movement, the experimental animals were killed, and their tissues were harvested for histological evaluation. When premolars in groups 1 and 2 were compared, group 1 showed higher rates of tooth movement until the eighth week of experimental tooth movement (P < .05). The amount of tooth movement was significantly greater in group 1 than in group 2 or in the control teeth (P < .05). In group 1, we observed considerable root resorption extending into the dentin, and the thickness of the dentin became approximately half that of the controls at the compression side adjacent to the distraction gap. This root resorption extended from the cementoenamel junction to the root apex. In group 2, root resorption on the compression side reached the dentin, but the root resorption was less than in group 1. These results indicated that heavy force and early orthodontic tooth movement are not recommended when teeth are moved through regenerated bone created by distraction osteogenesis, to avoid tipping and severe root resorption.