完全脱位牙即刻与延迟再植根吸收的动态观察

目的：动态观察实验大鼠再植牙牙根吸收及愈合过程，辅助临床治疗及预防再植牙牙根吸收。方法：30只6周龄SPF级Wistar雄性大鼠，分为6组，每组5只，其中一组为空白对照组。实验组大鼠双侧上颌第一磨牙脱位后再植，每只大鼠随机选取一侧脱位牙齿即刻再植，对侧同名牙则于体外干燥保存30min后再植回牙槽窝。分别于术后1、3、7、14、21d处死，分离上颌骨，拍摄x线片，应用IPP软件测量上颌第一磨牙近中根根周透影面积。标本脱钙后制作切片、HE染色，进行组织学观察。结果：再植牙根尖周透影面积随时间延长而增大，干燥组表现尤其明显；组织学上表现为初期炎症反应较明显，随着炎症发展，牙根表面吸收陷窝逐渐增多、增大，后期即刻组牙髓及牙周膜修复反应明显，干燥组牙槽骨修复反应强烈，牙根、牙周膜逐渐被类骨质样组织替代。结论：再植牙初期以炎症反应为主，后期主要表现为修复反应，即刻与延迟再植导致牙周膜细胞活性不同决定了再植牙根吸收的进展。

Dynamic observation of root resorption following tooth replantation

Objective：To dynamically observe the resorption and healing process of replanted tooth in experimental rats, so that we can assist the doctor in curing and preventing the root resorption in clinic ally. Methods：The experiment was carried out on thirty 6- week-old SPF Wistar male rats （n = 5 ） , which were randomly divided into six groups, with one of them blank group. The bilateral maxillary first molars of each rat in experimental groups were extracted. We randomly chose one of the molars to replant in the socket immediately,and the other one in the air for 30 minutes before replantation. The rats were sacrificed on day 1 ,day 3 ,day 7 ,day 14 and day 21 after replantation. Then we segregated the maxillae and scanned the specimens with X-ray, measured the shadow areas around the mesial roots of the maxillary first molars with IPP software. After decalcification of specimens, tissue slices were made and stained with HE for histological observation. Results：The shadow areas around the replanted teeth expanded over time, especially in the delayed replanting group ; the histological reaction of the teeth displayed is that the inflammation was severe at first and the resorption lacunae around the root grew more and bigger with the developing inflammation, then the pulp tissue and periodontal ligament began to recover by themselves in immediate replanting group and alveolar bone recovered strongly with root and periodontal ligament replaced by osteoid tissue in delayed replantation group. Conclusions：The reaction of the replanted tooth is mainly inflammation at initial stage but at the later stage recovery is the chief manifestation. The root resorption progress of the replanted tooth mainly depends on the vitality of periodontal ligament cells.