Effect of latency period before mandibular distraction on early osteogenesis in rabbits

Abstract

Recently, distraction osteogenesis is widely used in the cranial and maxillofacial skeleton. However, the need for a latency period before mandibular distraction remains controversial, with recommendations ranging from 0 to 14 days. We used a rabbit model to determine the ideal latency period for mandibular osteodistraction. We performed a bilateral subperiosteal corticotomy of the mandible and applied an external distraction device. We used 0-, 2-, 5-, and 10-day latency periods. Distraction was done at a rate of 0.5mm per day (0.25mm per 12 hours) for 10 days to elongate the mandible by 5mm after each latency period. Hematoxylin-eosin stain was used for histological observation, and bone was labeled by several fluorescence substances, which can be observed with a fluorescence microscope.
In the 0-day latency group, the lengthened region was filled with fibrous tissue. Cartilage-like islands were found along the lengthened region. In the 10-day latency group, the lengthened region was almost completely filled with woven bone. In the 2-and 5-day latency groups, there was a distraction gap, with mineralization zones at the periphery of this fibrous interzone. The primary osteon remodeling zone were located at both ends of the mineralization zones. In the 5-day latency group, newly formed bone was observed around the periosteum. These results indicate that 5 days is the most suitable latency period for mandibular distraction in the rabbit.