目的

探讨牙周膜牵引成骨中不同牵引速率移动牙张力侧牙周组织改建，及在牵引频率一定情况下的最适牵引速率，为临床应用提供客观理论依据。

方法

将7 只犬的下颌左右两侧随机分组，按每天牵引速率分为0.2、0.6、1.0 mm/d 三组和常规对照组、空白对照组。 实验组固定牵引频率1 次/天，每组分别以不同的牵引速率（0.2、0.6、1.0 mm/d）进行牵引，牵引1 周后维持3 d。 常规对照组使用镍钛螺旋拉簧对移动牙施力1 周。 取材行HE、Mallory's 三色染色，观察移动牙张力侧牙周组织改建。

结果

0.2 mm/d 组和0.6 mm/d 组移动牙张力侧牙周膜显著增宽，均显著宽于常规对照组，牙周膜细胞丰富，血管扩张，有明显新骨生成；1.0 mm/d 组牙周纤维断裂，组织水肿，未见新骨的生成。

结论

与常规对照组相比，牙周膜牵引成骨能促进牙周组织改建，加快牙齿移动。 但是牙周膜存在承载极限，在其极限范围内，牙周膜改建随牵引速率的增加更加活跃，超过其极限范围，牙周膜改建停止，出现永久性损伤。

Objective

To study the periodontal ligament （PDL） remodeling on tension side of moved-tooth through distraction osteogenesis with different distracting rate and find a suitable rate of distraction under a fixed distracting frequency.

Methods

The bilateral mandible of 7 male dogs were randomly divided into five groups according to the frequency of distraction：0.2， 0.6， 1.0 mm/day group， conventional control group and blank group. In experimental groups， the distractors were activated with a rate of 0.2， 0.6 and 1.0 mm/day respectively， once a day for one week； In conventional control group， the NiTi coil spring with 150 g force was used for tooth movement. The histological change of PDL was observed with HE and Mallory's trichrome stain.

Results

The histological study revealed that the periodontal ligament on tension side widened significantly in 0.2 mm/day and 0.6 mm/day groups compared with conventional control group. Fibroblasts and osteoblasts enriched in PDL and new bone spicules formed actively.Periodontal ligament lesions were observed and no new bone was formed in 1.0 mm group.

Conclusions

Distraction osteogenesis can accelerate the remodeling of periodontal ligament on tension side compared with conventional control group. Within the physiological load bearing capacity， the periodontal ligament remodeled more actively with the increasing rate. Above the load bearing capacity， periodontal ligament remodeling stops and permanent damage can be caused.