不同种类固定矫治器在切牙排齐初始阶段的摩擦力对比研究

摘要

Objective To compare the changes of the kinetic friction force and maximum static friction force of different fixed appliances during the initial leveling stage of incisors .Methods Typodont models of maxillary lateral incisors displaced 3mm horizontally were made and divided randomly into four groups including Group A of MDD ,Group B of MBT ,Group C of Tip‐Edge and Group D of self‐ligating .Each group consisted of five samples . The NITI wire of 0 .30mm was served as the alignment wire .The experimental typodont models were bathed in the constant temperature water of 45℃ for 30 minutes .The universal material testing machine was used to test the friction force of each model before and after the water bath .The kinetic friction force and the maximum static friction force were recorded .Results The kinetic friction force and the maximum static friction force increased with the ranking order as Group D ,Group A ,Group C and Group B before the water bath ,and there were significant differences between the groups (P<0.05) .The friction force changed after the water bath ,and the reduction rate was the lowest in Group A and the highest in Group D . Except between Group B and Group C , there were significant differences between the groups (P<0.05) .Conclusion The friction force of the MDD appliance is low during the initial levelling stage of the maxillary lateral incisors ,which has negative effect on the orthodontic leveling and aligning to a certain degree .Therefore ,the feature of its light force correction needs further verifications in both scientific research and clinical practice .%目的：比较4种不同类型固定矫治器在上颌切牙排齐初始阶段的动摩擦力和最大静摩擦力的变化。方法 Typodont模型上翻制上颌双侧侧切牙腭向水平3 mm异位的模型，随机分为4组，分别为A组（MDD）、B组（MBT ）、C组（Tip‐Edge）和D组（自锁），每组5个样本。0.30 mm镍钛圆丝作为初始排齐弓丝，45℃恒温水浴30 min ，使用万能材料试验机对水浴前后各组模型进行动摩擦力和最大静摩擦力的测试并记录。结果4组矫治器水浴前最大静摩擦力和动摩擦力的力值排序为：D组＜ A 组＜C组＜B组，组间比较，差异有统计学意义（P＜0.05）。水浴后摩擦力降低率计算结果为：A组最小，D组最大，除B组与C组比较差异无统计学意义（ P＞0.05）外，其余各组间比较差异均有统计学意义（ P＜0.05）。结论 M DD矫治器在上颌切牙排齐初始阶段摩擦力较低，一定程度上影响牙齿排齐效果，其轻力矫治的特点有待进一步研究及临床验证。