Amount of bone lengthening affects blood flow recovery and bone mineralization after distraction osteogenesis in a canine cleft palate model.

OBJECTIVES: Distraction osteogenesis has been applied to the craniofacial region. To reduce the cleft width of patients with cleft lip and palate, alveolar bones are distracted toward the cleft. However, no reports have described limitations to the amount of lengthening that can be achieved by distraction osteogenesis in this area. Therefore, we investigated the healing process following different extents of distraction osteogenesis using a canine cleft palate model. METHODS: A 10-mm bone defect was made in the palates. A bony segment including the canine was prepared and translocated into the defect area at a rate of 1 mm/d for 6 or 10 days, resulting in two groups (6- and 10-mm groups). Canine pulpal blood flow was monitored for 100 days with Doppler flowmetry. Then, the animals were sacrificed and the regenerated bone area was evaluated radiologically and histologically. Statistical significance was confirmed with the Mann-Whitney rank test. RESULTS: Pulpal blood flow in the 6-mm group recovered to original levels earlier than in the 10-mm group. Cortical bone density in the regenerated bone, measured by peripheral quantitative computed tomography, was significantly greater in the 6-mm group than in the 10-mm group. The amount of regenerated bone in histologic sections was also significantly greater in the 6-mm group. CONCLUSION: We clearly showed that healing progress depends on the extent of distraction osteogenesis, highlighting the importance of limited distraction osteogenesis in the alveolar area.

The effects of hyperbaric oxygen on tooth movement into the regenerated area after distraction osteogenesis.

OBJECTIVE: To analyze the effect of hyperbaric oxygen on newly formed bone in distracted areas surrounding the root of a moving tooth by histological and radiological analysis. It was hypothesized that the application of hyperbaric oxygen to a tooth moving into the distracted area would accelerate ossification and vascularization of newly formed bone in the distracted space. DESIGN: Ten dogs were used. After creating a 10-mm-long bone defect, a bony segment was prepared and translocated into the defect area at a rate of 1 mm/d for 10 days. Following the distraction period, tooth movement was started and the dogs were divided into two groups. The HBO group received hyperbaric oxygen; whereas, the control group did not. At 150 days after tooth movement, the distracted area around the moving tooth was evaluated radiologically and histologically. Differences between groups were confirmed by a Mann-Whitney U test. RESULTS: Trabecular bone density and cortical and subcortical bone areas measured by peripheral quantitative computed tomography in the HBO group were significantly higher than those in the control group. Histological observations revealed regenerated bone and blood vessels 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 than in the control group. CONCLUSIONS: Applying hyperbaric oxygen to tooth movement into a distracted area appears to accelerate ossification and vascularization of regenerated bone in the that area.

[Observation of pulpal blood flow and bone mineralization after alveolar distraction osteogenesis in a canine cleft model].

OBJECTIVE: Distraction osteogenesis has been widely used for the craniofacial region and even applied to alveolar bones to reduce the cleft width of cleft lip and/or palate patients. However, there have been no reports on the limitations on the total amount of lengthening that can be accomplished by distraction osteogenesis in this area. Therefore, we investigated how different extents of distraction osteogenesis affect the healing process using a canine cleft palate model. METHODS: Six beagle dogs were used in this study. A bony segment including the canine was prepared and translocated into a 10-mm bone defect area, imitating a cleft, at a rate of 1 mm/day for six or ten days, resulting in two groups (6- and 10-mm groups). Canine pulpal blood flow was monitored for 100 days by Doppler flowmetry. The animals were then sacrificed and the regenerated bone area was evaluated using peripheral quantitative computed tomography (pQCT) and a histological process. Statistical significance was confirmed by the Mann-Whitney rank sum test. RESULTS: Pulpal blood flow recovered to the original levels significantly earlier in the 6-mm group. It was shown by pQCT evaluation that cortical bone density in the regenerated bone was significantly higher in the 6-mm group. The amount of regenerated bone in histological sections was also significantly higher in the 6-mm group than in the 10-mm group. CONCLUSION: We revealed that the amount of bone lengthening affects the progress of healing. These results suggest the importance of limited distraction osteogenesis in the maxillofacial area.

Mandibular distraction osteogenesis for treatment of extreme mandibular hypoplasia.

Distraction osteogenesis is an important option for the treatment of mandibular hypoplasia. This case report describes the treatment of a girl with mandibular hypoplasia and sleep apnea. She had a tracheostomy, followed by orthodontic treatment, including extraoral mandibular distraction osteogenesis to open the airway. Follow-up records 4 year 8 months after the distraction osteogenesis are presented.