螺旋弹簧与橡皮链远牵尖牙力学性能比较分析

Comparison and analysis of mechanical properties between coil spring and elastomeric chain in canine retraction

目的 比较分析螺旋弹簧与橡皮链远牵尖牙的力学性能,以助提高临床疗效。方法 第一部分为体外模拟实验,应用CH-0-1型齿科正畸力测量仪对5mm长的螺旋弹簧及三个圈长的橡皮链进行拉伸实验至于150克,比较两者在人工唾液中不同时期不同位移时力值衰减程度的力学性能。第二部分为临床应用研究。结果 在模拟口腔环境及尖牙移动的相同实验条件下,螺旋弹簧在28天内力值衰减明显低于橡皮链,前者衰减2.9％,后者衰减42.8％。在150克初始正畸力作用下,螺旋弹簧远牵尖牙的速率快于橡皮链。结论 螺旋弹簧的力学性能优于橡皮链,力值越持续,越适宜牙齿移动。力的持续时间是决定牙齿移动速率的重要因素。

Objective This study was designed to compare the mechanical properties between coil spring and elastomeric chain in canine retraction using sliding mechanics for the sake of providing clinical reference and improving treatment effect. Methods The first part was a stimulated experiment. The stretching test of coil spring with length of 5mm and elastomeric chain of three units was undertaken by CH-0-1 orthodontic force gauge to provide a force of 150 grams. The force decay between the coil spring and the elastomeric chain was compared in different periods and different displacement under a stimulated oral environment. The second part was a clinical study. Results Under a stimulated oral environment and canine movement in a clinical condition, the force decay of the coil spring was lower evidently than the elastomeric chain within 28 days. The former decayed 2. 9%, the latter decayed 42. 8%. The coil spring could improve the rate of canine retraction. Conclusion The coil spring is superior to the elastomeric chain in the mechanical properties. The more constant the force is, the more suitable the tooth movement. The duration of force application seemed to be a critical factor in regulating rate of tooth movement.