Microvascular soft tissue changes in alveolar distraction osteogenesis

Objective. The aim of the study was to quantify the effect of distraction osteogenesis on the changes in vascular density in the human oral mucosa. Material and methods. Alveolar distraction was performed in 10 patients with alveolar ridge deficiencies, while in the contralateral nondistracted site an implant was placed. The distraction device was activated after 7 days of latency starting with a distraction rate of 1 mm a day for a 1-week period. After completion of distraction the segments were held in fixation for 6 weeks. Microvascular images were obtained with the use of orthogonal polarization spectral imaging. From day 1 postoperatively until the end of consolidation, microvascular changes in capillary density were assessed. Results. All patients had a good response to the osseous distraction. No dehiscence or infections were observed. In all patients microvascular changes consisted of a bilateral decrease in capillary density and capillary index immediately following surgery. No significant differences between the distraction site and nondistracted implant site were observed during the latency phase or consolidation phase. Capillary vessel count revealed a mean of 14.6 +/- 2.7 vessels per visual field (VF) at day 5 of distraction versus 16.6 +/- 2.9 vessels/VF in the nondistracted site, which increased to a mean of 33.4 +/- 4.0 vessels/VF at day 10 of distraction compared to 24.0 +/- 0.8 vessels/VF in nondistracted implant sites. During the consolidation period the mean number of vessels was comparable to preoperative levels (mean 26.0 vessels/VF). The increase in capillary density and capillary index was more pronounced during the activation phase of distraction compared to the implant site. Conclusion. The increase in vascular response during distraction osteogenesis mainly occurs in the activation phase of distraction