ABSTRACT
<p><b>OBJECTIVE</b>To observe the effect of simvastatin carried by poly (lactide-co-glycolide) (PLGA) on residual ridge resorption following tooth extraction.</p><p><b>METHODS</b>Sixty male Wistar rats were divided into experimental groups and control groups (30 rats/group). PLGA was immediately implanted with or without simvastatin into extraction sockets of the mandibular incisors. Soft X-ray photography, bone mineral density (BMD) and histopathologic study were conducted at 7, 14, 28, 56, and 84 days after implantation.</p><p><b>RESULTS</b>The relative length values of residual alveolar ridge of the experimental groups were greater than those of the controls at 14, 28, 56, and 84 days after implantation, and there was a significant difference between the experimental and control groups (P < 0.05). The BMD of the specific region was higher in the experimental groups [(7.101 +/- 0.025), (7.178 +/- 0.039), and (7.162 +/- 0.052) g/cm(2)] than that in the control groups [(7.074 +/- 0.014), (7.117 +/- 0.012), and (7.059 +/- 0.037) g/cm(2)] (P < 0.05) after 28, 56, and 84 days. Light microscopy showed that bone formation rate and quality of the experimental group were better than those in the control group at the same time.</p><p><b>CONCLUSIONS</b>Simvastatin carried by PLGA could induce bone formation of tooth socket. Local application of simvastatin would be potential to preserve the length and bone volume of alveolar ridge after tooth extraction.</p>