The Effect of Chitosan on Bone Formation in Distracted Mandibular Bone of Dog

Kim, Il Hwan; Park, Jae Woo

Abstract

The purpose of this experiment was to study the effect of chitosan on the osteogenesis in the distracted zones of mandibles. Eight dogs were used for this study. Mandibular distraction was started 5 days after the mandibular osteotomy at a rate of 2mm per day for a total of 10mm distraction for 5 days. The experimental group was divided into control group(n=4) and chitosan group(n=4) depending on the type of the injected material into the distracted area. On the day of completion of distraction, a 1ml volume of hyaluronic acid solution was injected in the distracted area of control group and 1ml of injectable solution of chitosan mixed with hyaluronic acid was done in chitosan group. After injection of the materials, the distraction device was left in place for 3 or 6 weeks to allow for bony consolidation. Two dogs in each group, a total of four dogs, were sacrificed at 3 weeks, and another four dogs at 6 weeks after completion of distraction, and bone specimens of the distracted mandibles were taken after radiographs for histologic examination. In the radiographs of the distracted areas of the mandibles, the control group had shown a mostly radiolucent zone but the chitosan group had shown the bilateral radiodense zones and central radiolucent zone. Bilateral radiodense zones were more extended into the center of the distracted area following passage of time and vertical thickness of the radiodense zone was about two times wider in 6 weeks than in 3 weeks after finishing bone distraction. In the histological findings, the control group showed whole fibrous tissue but the chitosan group showed bilateral new woven bones and central narrow fibrous interzone. In conclusion, there was more new bone formation in the distracted area of the mandible in case of injection of chitosan. These findings suggested that injectable chitosan appears to be effective in early bony consolidation in distraction osteogenesis.