Effects of Simvastatin on Mandibular Distraction Osteogenesis

Purpose: The aim of this study was to evaluate the effects of local and systemic simvastatin application on distraction osteogenesis. Materials and Methods: Eighteen New Zealand white rabbits underwent unilateral mandibular distraction osteogenesis. After 7 days of neutral fixation, 0.4 mm twice per day, distraction was performed for 10 days. Simvastatin was applied locally during the osteotomy phase with a gelatin sponge carrier and systemically during the distraction osteogenesis period by oral gavage. All animals were killed at the end of the consolidation period of 14 days. The distracted mandibles were harvested and evaluated by plain radiography, by peripheral quantitative computed tomography, and with histomorphometry. Results: Radiographic evaluation with peripheral quantitative computed tomography showed that the area of the regenerate increased by 9.6% in the local simvastatin group and by 19.3% in the systemic simvastatin group as compared with the control group. In both experimental groups the density of the regenerate increased by 6.7% as compared with the control group. Statistical evaluation of radiographic data showed that all of these changes were not significant. Histomorphometric evaluation determined that there was no statistical difference among groups with regard to the ratios of bone tissue volume to fibrous tissue volume and bone tissue volume to marrow tissue volume. Conclusions: The results of this study suggest that simvastatin's effect on enhancing distraction regenerate is limited with the applied doses and methods. (C) 2008 American Association of Oral and Maxillofacial Surgeons