[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.