螺旋弹簧和橡皮链拉尖牙向远中的临床效果研究

Clinical effects of Ni-Ti coil spring and elastic chain on distal movement of canines

目的研究Ni-Ti螺旋弹簧和橡皮链施力后,尖牙远中移动速率、龈沟液(gingival crevicular fluid,GCF)中碱性磷酸酶(alkaline phosphatase,ALP)活性,探讨不同持续张力的正畸效果和生物学效应。方法用OPAK直丝弓矫治技术托槽,排齐整平后,采用0.018×0.025″SS的Ni-Ti方丝进行尖牙远中移动。然后,用初始力150g的Ni-Ti螺旋弹簧和橡皮链牵引尖牙向远中,21d后,采用游标卡尺测定牙齿移动距离,Beckman全自动生化分析仪检测龈沟液中碱性磷酸酶(GCF-ALP)的活性。结果螺旋弹簧和橡皮链施力21d后,尖牙向远中移动距离差异有显著性(P<0.05)。在螺旋弹簧和橡皮链持续牵引力作用下,GCF-ALP活性随时间推移逐渐增加,6个月时达到最高水平,与加力前比较,差异有显著性(P<0.05);6个月后,GCF-ALP开始下降,12个月时,橡皮链加力侧GCF-ALP活性基本恢复到加力前的水平。但在6和12个月时,GCF-ALP活性在螺旋弹簧施力侧显著高于橡皮链施力侧,差异有显著性(P<0.01)。结论螺旋弹簧拉尖牙向远中移动速率较快,产生的生物学效应较强而持久。

[Objective] To study the rate of distal movement of canines and the alkaline phosphatase activity in gingival crevicular fluid（GCF-ALP） after retracted by Ni-Ti coil spring and elastic chain, and the orthodontic and biological effects of different permanent strains. [Methods] Edgewise technology was used to push the maxillary canines moveing distally by Ni-Ti coil spring and elastic chain, which produced 150 g original force in both. 21 days later, the moving distances of canines were detected by vernier caliper, and GCF-ALP activity was analyzed by Beckman automatic analysis meter. [Results] After 21 days retracting, there were significant difference in moving distances of canines in Ni-Ti coil spring side and elastic chain side （P 〈0.05）. The GCF-ALP increased No ita time, and reached the highest level in Ni-Ti coil spring and elastic chain side, at the end of 6 months. The GCF-ALP activity was significantly higher than that before giving strains. However, the GCF-ALP activity gradually dropped to a low level, and recovered to the normal level in elastic chain side after 12 months. The GCF-ALP activity in coil spring side was significantly higher than that in elastic of 6 and 12 months respectively （P 〈0.05）. [Conclusion] Comparing with elastic chain, there are higher distal moving rate and more permanent biological effects in coil spring.