直丝弓滑动技术拔牙矫治骨性Ⅱ类错的Steiner分析

Steiner analysis of treatment of skeletal class Ⅱ malocclusion using preajusted appliance and sliding mechanics

目的 :探讨直丝弓滑动技术拔牙矫治骨性 类错牙合的治疗变化和代偿机制。方法 :选择 16例骨性 类错牙合患者 ,平均年龄 12 .1岁。拔除 4个第一前磨牙 ,应用直丝弓滑动技术治疗。进行治疗前后 X线头影测量Steiner分析 ,并做配对 t检验和逐步回归分析。结果 :SNA角减少 1.1°,SNB角增加 1.3°,上切牙回收 4.1mm,下切牙回收 1.3mm。治疗后 U1NA角为 2 1.3°,L1NB角为 33.0°。得到回归方程 :ANB=0 .19× L1NB-0 .10× U1NA+ 0 .2 7。结论 :直丝弓滑动技术拔牙矫治骨性 类错牙合 ,可使上切牙大量的内收 ,下切牙少量后移 ,同时上下颌骨发生了生长或改建。矫治骨性 类错牙合的代偿机制主要依靠下切牙一定程度内的唇倾 ,而上切牙牙轴的代偿作用不太明显 。

Objective:To investigate the changes of some occlusion related parameters and compensation mechanism in correction of skeletal class Ⅱ malocclusion using preajusted appliance and sliding mechanics.Methods:Sixteen patients aged 12.1 years old on the average with skeletal class Ⅱ malocclusion were involved.Four first premolars of each case were extracted.All cases were treated by the straight wire appliances of Roth set up and sliding mechanics.Steiner analysis was performed before and after treatmen. Paired t test and stepwise regression analysis were used.Results:SNA was reduced by 1.1°,SNB was enlarged by 1.3° ,upper and lower incisors were retracted by 4.1 mm and 1.3 mm respectively.After treatment,lower incisors were a little proclined.The regression equation was:ANB=0.19×L1NB-0.10×UlNA+0.27。Conclusion:Correction of skeletal class Ⅱ malocclusion using straight wire appliance and sliding mechanics is mainly achieved by retraction of upper incisors and proclination of lower incisors.