不同舌侧牵引力对关闭拔牙间隙速度影响的实验研究

Effect of varying lingual traction forces on the space-closing speed in a typodont model

目的在Typodont模型上,模拟临床应用颊侧镍钛丝拉簧加舌侧弹性牵引一步滑动关闭拔牙间隙的过程,研究在舌侧加不同力值对关闭间隙速度的影响。方法制作42个安氏I类双颌牙齿前突的标准Typodont模型,随机分成7组,每组6个模型,将模型的四个区左右配对分组,奇数牙弓的左上区和左下区为实验组,右上区和右下区为对照组;偶数牙弓与之相反。实验组使用颊侧镍钛丝拉簧加舌侧弹性牵引关闭间隙,分别加0、5、10、15、20、25、30g大小的舌侧牵引力;对照组单纯使用颊侧镍钛丝拉簧牵引关闭间隙,研究比较其对滑动速度的影响。结果对照组的间隙关闭速度显著低于5、10、15、20、25g舌侧牵引力实验组(P<0.05),显著高于30g舌侧牵引力实验组(P<0.05);15g舌侧牵引力实验组的间隙关闭速度显著高于其它各组(P<0.05)。结论应用颊侧镍钛丝拉簧加舌侧弹性牵引一步滑动关闭拔牙间隙速度显著快于传统的单纯使用颊侧镍钛丝拉簧,舌侧牵引力为15g时滑动阻力最小,间隙关闭速度最快。

Objective To investigate the influences of varying lingual traction forces on the space-closing speed in a typodont model.Methods Forty-two Angle Class I standard typodont models of bimaxillary teeth protrusion were divided into 7 equal groups.Four regions of the model were paired to groups,and in the odd-numbered models,the top left and bottom left regions served as the experimental group and the top right and bottom right regions as the control group;in the even-numbered models,the regions in the model were grouped oppositely.In the experimental group,the space was closed by niti wire extension spring in the buccal ridge combined with lingual elastic traction of 0,5,10,15,20,25 and 30 g.In the control group,the space was closed by exclusive niti wire extension spring in the buccal ridge.The space-closing speed were analyzed in all the groups.Results The space-closing speed was significantly lower in the control group than in the experimental groups with lingual traction forces of 5,10,15,20 and 25 g（P〈0.05）,but a traction force of 30 g resulted in a significantly lower speed than that in the control group（P〈0.05）.The space closing speed was the greatest in the experimental group with a traction force of 15 g（P〈0.05）.Conclusion Niti wire extension spring in the buccal ridge combined with lingual elastic traction results in faster space-closing speed than traditional exclusive niti wire extension spring.The speed is the fastest by applying 15 g lingual traction,which is also associated with the lowest slip resistance.