Effects of Hyperbaric Oxygen on Tooth Movement after Distraction Osteogenesis

Objectives: We have reported that bone mineral density (BMD) of regenerated bone is increased in adult beagle dogs after distraction osteogenesis (DOG) with hyperbaric oxygen (HBO) compared with that without HBO. Clinically, orthodontic tooth movement into the regenerated bone after DOG has been performed for the reconstruction of occlusion, but it is unknown how alveolar tissue is changed by tooth movement into regenerated bone. The purpose of this study was to examine the effect of HBO on newly formed bone in distracted areas surrounding the root of a moving tooth by histological and radiological analysis. Methods: Ten female beagle dogs (age 11.3±0.7 months) were used in the study. After creating a 10-mm length bone defect, a bony segment was prepared and translocated into the defect area at a rate of 1 mm/day for 10 days. Following the distraction period, tooth movement was begun and the dogs were divided into 2 groups. The HBO group received HBO while the control group did not receive HBO. One hundred fifty days after tooth movement, the distracted area around the moving tooth was evaluated radiologically and histologically. Differences between groups were confirmed by the Mann-Whitney rank test (P<0.05). Results: Trabecular bone density and cortical and subcortical bone area measured by peripheral quantitative computed tomography were significantly higher in the HBO group than those in the control group. Histological observations revealed regenerated bone and blood vessel formation in the tension site of the moving tooth in the HBO group. The regenerated bone structure measured by bone histomorphometry was larger and more active in bone formation in the HBO group compared with controls. Conclusion: Applying HBO to tooth movement into a distracted area appears to accelerate ossification and vascularization of regenerated bone in the distracted area.