Establishment of residual ridge resorption model of rats after the mandible incisor was extracted
Wu Zhe, Sun Hongchen, Che Yanhai, et al.College of Stomatology,Jilin University,Changchun 130041,China
【Abstract】 Objective：To establish an experimental model of residual ridge resorption after mandibular incisor extraction and to study the occurrence mechanisms. Methods：Thirty male Wistar rats were used, the edge of the right mandibular incisor was cut every three days(a total of three times) and the incisor was extracted at three days after the final cut. The animals were sacrificed 0,1,2,4,8,12 weeks respectively after the extraction and the mandibles were dissected out. The length of the alveolar bone and the ratio of extracted side length to unextracted side length were measured on soft X-ray photographs and the mandibles were processed for histomorphometry.Eighteen male Wistar rats were used to observe the morphologic alteration of periodontal tissues by hematoxylin and eosin when the incisor crown was cut at different time intervals. Results： As compared with the unextracted side, the length of alveolar ridge of the extracted side was significantly decreased at 4,8,12 weeks;the ratio of extracted side length to unextracted side length significantly decreased at 4 week after tooth extraction（P<0.05）. In histomorphometry, new bone were seen at the tooth socket and the residual blood clot decreased at 2 week after tooth extraction; the tooth socket was filled with new formed bone at 8 weeks after tooth extraction and could not distinguish the threshold between the new bone and the alveolar bone. After the crown was cut, the periodontal tissue appeared to be edema, the principal fibrous bands was rupture and lose functional arrangement, blood sinus was increased, and all the above became serious as time passed. Conclusion： Extracting mandibular incisors may be a simple methods in developing an animal model of residual ridge.
【Key words】 Alveolar bone resorption;Animal models