Effects of Latency on Bone Formation during the Consolidation Period of Rabbit Mandibular Distraction

Objective: To investigate the effect of latency on bone formation during the consolidation period in mandibular distraction osteogenesis in rabbits.Materials and Methods: Thirty young adult Japanese white rabbits were divided into 4 groups. Nine animals each were allocated to groups A, B and C, where bilateral mandibular corticotomy was performed and an external distraction device fixed. Three animals were used as controls for each experimental group (group D). Latency periods of 0 days (group A), 5 days (group B), and 10 days (group C) were observed before the start of distraction. Distraction was carried out at a rate of 0.25 mm every 12 hours to lengthen the mandible for 10 days. The rabbits were sacrificed at 3 stages — immediately after completion of distraction, after 5 days of early consolidation, and after 10 days of late consolidation — in all groups. The distracted mandibles were examined using haematoxylin and eosin stain for histology at various stages. The bone mineral densities were examined using peripheral quantitative computed tomography after 10 days of consolidation.Results: Histological study showed that the 10-day latency group exhibited good bone formation when compared with the 0- and 5-day latency groups during the early stages of consolidation. However, bone mineral densities of the experimental groups showed no statistically significant differences after 10 days of consolidation.Conclusion: A change in latency does not alter the properties of the regenerate bone in rabbit mandibular distraction osteogenesis after a period of consolidation.