狗牙周膜血管构筑及正畸力作用下的即时改变

The Microvasculature of the Dog's Periodontal Ligament and Its Immediate Response to Orthodontic Forces

将狗一侧下颌前磨牙施以２００ｇ近中水平向正畸力，作用时间为２ｈ，另一侧作为对照组进行自身对照。分别将甲醛墨汁和树脂灌注液经双侧颈外动脉插管和下牙槽动脉插管灌入牙周膜血管。用光镜和实时图像分析仪观察分析墨汁切片，用扫描电镜观察牙周膜微血管铸型。结果显示，牙周膜微血管系统中有形态特殊的血管吻合支和毛细血管襻；在牙周膜与牙龈、牙髓、牙槽骨和邻牙牙周膜之间存在广泛的交通支，形成一个有机的牙周血运网络系统；一些微静脉在穿出Ｖｏｌｋｍａｎ＇ｓ管前形成“储水池”样膨大结构。借助于扫描电镜，可以从微血管铸型上的血管内皮细胞核压迹的特征来判别微动脉和微静脉。定量分析结果显示实验组牵张区牙周膜微血管体密度大于对照组对应区；

The purpose of this study was to examine the microvascular architecture of dog's periodontal ligament (PDL) and its immediate response to horizontal orthodontic force. A force of 200 g was applied mesially to the mandibular premolar of a dog for 2 hours, the distal side served as the contrast side. Formalin ink was perfused into the carotid arteries bilaterlly through the cannulas. After perfusion the mandible was decalcified, celloidin embedded, serially sectioned and stained with eosin. The sections were then observed by light microscope and analyzed by image analyzer. Vascular corrosion casts were prepared by the similar way with the formalin ink perfusion and examined by scanning electron microscope. The results showed: there were extensive interconnections among the PDL, dental pulp, gingiva, alveolus and the neighbour tooth PDL, which would benefit the maintenance of health and functions of the dental pulp and the periodontal tissues. Arterioles and venulae could be confirmed by the presence of characteristic differences of nuclear impressions in endothelial cell under the scanning electron microscope. The quantitative analysis showed that the tensioned PDL sites in the experimental group had a higher microvascular volume density than the corresponding sites in the contrast group, while the pressed PDL sites in the experimental group had a lower microvascular volume density than the corresponding sites in the contrast group. This should result from the hydraulic mechanism in the PDL.