正畸力对自体移植牙牙周愈合影响的实验研究

Effect of orthodontic force on periodontal healing after autotransplantation： an experimental study

目的观察术后施加正畸力时间对犬移植牙牙周愈合的影响，以期为临床提供参考。方法将4只犬的32颗上下颌切牙进行自体移植手术，分为术后不加力组（对照组）和术后1、2、4周加力4组，术后8周处死动物，将移植牙及牙周组织制作脱钙标本，以垂直于牙长轴方向进行切片，光镜下分别计算每颗牙根表面3种形态：正常牙周膜、牙根吸收和骨性粘连的观察点占全部240个观察点的百分比，比较各组百分比。结果与对照组相比，术后2周加力组牙根吸收和骨性粘连百分比均降低，骨性粘连降低至2．1％，与对照组（12．5％）差异有统计学意义（P〈0．05）。虽然术后1周加力组骨性粘连百分比（6．3％）降低，但牙根吸收增加为68．8％，与对照组（12．5％和41．7％）差异均有统计学意义（P〈0，05）。术后4周加力组正常牙周膜的百分比与对照组差异无统计学意义（P〉0．05）。结论术后2周加力更有利于牙周愈合，过早加力反而不利于牙周愈合。

Objective To investigate the effect of the continuous light force to the donor teeth on the periodontal healing after transplantation. Methods Thirty-two maxillary and mandibular incisors in four lO-month-old male Beagle dogs were autotransplanted. The pulps were removed in all teeth. The teeth were divided into four groups, one control and three experimental groups. In control group （ group 1 ） , the teeth were unloaded. In the other three experimental groups, continuous force （ 0. 49 N） was applied in the 1 st （ group 2 ） , 2nd （ group 3 ） and 4th （ group 4 ） week, respectively. The dogs were sacrificed in the 8th week. The tissue blocks were demineralized and sectioned perpendicular to the long axis of the teeth. The histological analysis was made. Results Histomophometric analysis revealed a significantly lower occurrence of replacement root resorption in the group 3 （2. 1% ） than in the control group（ 12. 5%, P 〈 0. 05 ）. The significant lower incidence of replacement root resorption, and a higher surface and inflammatory root resorption were found in group 2（6. 3% and 68. 8% ） than in the control group（12. 5% and 41.7%, P 〈 0.05 ）. No significant difference was found between group 4 and control group （ P 〉 0.05 ）. Conclusions The orthodontic force promoted the regeneration of the periodontal ligament and prevented dentoalveolar ankylosis, whereas excessive initial force might cause root and bone resorption.