Effect of Recombinant Human Bone Morphogenetic Protein-2 on Mandibular Distraction at Different Rates in a Rabbit Model

This study aims to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on mandibular distraction at routine and rapid distraction rates. Eighteen New Zealand white rabbits were assigned to 2 groups, 1 treated at a routine distraction rate (0.9 mm/d) and the other at a rapid distraction rate (2.7 mm/d). rhBMP-2 was injected into 1 side of the distraction regenerate at the end of the active distraction period; the contralateral side was used as a control. The distraction regenerates were analyzed by plain radiography, microcomputed tomography, and histologic examination. The results showed that rhBMP-2 can promote bone formation at both rapid and routine distraction rates, but no statistically significant difference was observed between the bone morphogenetic protein injection sides of the rapid and routine distraction groups. In conclusion, the study indicates that rhBMP-2 can enhance bone ossification at both routine and rapid distraction rates. The addition of rhBMP-2 seems to be able to compensate for the rapid distraction rate in mandibular distraction osteogenesis. Further longterm follow-up and mechanical strength test for the support of implants or conventional prostheses are necessary.