无牙颌对兔颞下颌关节影响的组织病理学观察

Effects of total edentulousness on temporomandibular joints in rabbits:A histolo gical study

目的:探讨在无牙颌状态下颞下颌关节的组织学改变。方法:将14只健康成年新西兰白兔等量分为7组,其中1组为对照组,其余6组为实验组。实验组动物在全麻下一次性拔除全口牙齿,使其成为无牙颌状态,分别于术后1、2、4、8、16周和26周将实验动物麻醉过量致死后,将双侧颞下颌关节完整取出,进行组织学观察。结果:实验组动物的髁状突纤维层疏松、玻璃样变性,纤维间的间隙增宽,表面粗糙;增殖层、肥大层和钙化软骨层均变薄或消失;骨髓腔内有灶性出血及显微骨折现象;关节盘纤维间间隙增宽,表面有断裂现象,关节盘软骨细胞灶性增多或聚集;关节盘与髁状突发生粘连。结论:牙列缺失后颞下颌关节发生退行性改变,从而支持无牙颌与颞下颌关节紊乱病有关。

Objective:To study the effects of total edentulousness on t he temporomandibular joints in rabbits. Methods:14 adult New Zea land white rabbits were divided into 7 groups with 2 animals in each. One group was the control and the other six groups were experimental. In the experimental groups, all the teeth of the rabbits were extracted under general anesthesia. Th e rabbits in each experimental group were sacrificed respectively at 1,2,4,8,16 and 26 weeks after operation. Then the bilateral temporomandibular joints of eac h experimental animal were removed entirely and examined histologically. Results:In all the experimental groups, changes were observed in the con dyle microstructure: the fiber layer loosened and hyalinized, the spaces between fibers enlarged, and the surface of fiber layer became rough; the proliferative cell layer and the calcified cartilage layer as well as the hypertrophic layer became thinner or partly disappeared; focal hemorrhage occurred in marrow cavity . Meanwhile,in the discs, the spaces between fibers increased; the surface of th e discs cracked. Micro-fracture in condyle was found and clustering of chondroc ytes in the discs were oberved occasionally. In addition, the condyles adhered t o the discs somewhere. Conclusion:Total edentulousness may lead to temporomandibular joint degeneration.