EFFECT OF BONE MORPHOGENETIC PROTEIN ON A RABBIT MANDIBULAR DISTRACTION OSTEOGENESIS

ABSTRACT

Distraction osteogenesis refers to the biological process responsible for new bone formation between bone segments by gradual distraction after osteotomy. Recently, distraction osteogenesis has been widely used in the craniomaxillofacial skeleton. For the past several years, various inconveniences including a protracted total distraction period required patients to wear a distractor frame longer. Furthermore, side effects such as pin tract infections and soft tissue swelling may arise due to the long treatment period. These drawbacks form the rationale of this study which purports to seek a method by which the total distraction period can be reduced. This paper examines how bone morphogenetic protein(BMP), known to facilitate osteogenesis, influences bone formation when applied in distracted area. We used a rabbit model and performed a subperiosteal corticotomy of the bilateral mandible and then applied an rhBMP-2 and external device. sixteen rabbits were divided into 4 group by differnet latency periods, and by BMP group and control group. Distraction was done at rate of 0.7mm per day to elongate by 4.2mm after each latency period. After distraction, it allowed consolidation for 7 days or 14 days. At the end of consolidation, rabbits mandibles were harvested and clinical examination, radiogrphic evaluation, histological and histomorphometrical examinations were conducted. The results were new bone formation were increased in the BMP treatment site than in control on every latency group at consolidation 1 and 2 weeks, More bony trabeculae area was formed in the BMP treated site on shorter latency periods than in control on longer latency periods and More bony trabeculae was formed in the BMP treated site at consolidation 1 week than in control at consolidation 2 weeks. As the results, BMPs stimulate bone formation. Also tissue adhesive as the carrier of BMP are useful for clinical application.