螺旋扩弓器在前方牵引治疗替牙期骨性Ⅲ类错畸形中的疗效评估

Role of expansion screw in treatment of skeletal Class Ⅲ malocclusion with maxillary protraction in mixed dentition

目的 探讨螺旋扩弓器对前方牵引治疗替牙期安氏Ⅲ类骨性错牙合疗效的影响。方法 选择8.5~11.0岁替牙期安氏Ⅲ类骨性错牙合的患者32例,随机分为2组,A组16例采用单纯前方牵引,B组16例先行上颌快速扩弓2周后再行前方牵引。治疗时间为6~9个月。疗程结束后,将2组患者的术前、术后头颅侧位片进行描点测量,用SPSS 13.0统计软件进行统计处理,对2组矫正前后的变化进行配对t检验分析。结果 1A组中有3例在疗程结束时前牙呈对刃关系,其余13例治疗结束后反牙合解除,前牙覆牙合、覆盖正常;B组患者16例在疗程结束时反牙合全部解除,前牙覆牙合、覆盖正常。2矫治后2组SNA、Ptm-A、ANB、Wits、U1-SN、ANS-Me、FH-MP均明显增大,差异有统计学意义（P〈0.05）,且联合扩弓组的Wits、ANS-Me、FH-MP增大较单纯牵引组显著,差异有统计学意义（P〈0.05）;单纯牵引组的U1-SN增大及SN-PP、L1-MP的减小较联合扩弓组显著,差异具有统计学意义（P〈0.05）,组间差异也有统计学意义（P〈0.05）。结论 前方牵引治疗替牙期安氏Ⅲ类骨性错牙合,无论是否联合扩弓,都能取得显著的效果,联合扩弓的方法可减少上下前牙的唇倾、减少腭平面的逆时针旋转,效果更令人满意。

Objective To investigate the effect of anterior protraction with expansion screw in the treatment of skeletal Class Ⅲ malocclusion in mixed dentition. Methods Thirty-two children with skeletal Class Ⅲ malocclusion were ran- domly divided into two groups. Sixteen patients of group A received simple protraction, while the other sixteen patients of group B received the rapid maxillary expansion for two weeks followed by maxillary protraction. The treatment time was six to nine months. After the treatment, the cephalometric measurement in lateral X-ray film was done to compare the differ- ence using t-test by SPSS. Results （1）In group A,the anterior teeth of both jaws met along their incisal edges in 3 cases, and crossbite was relieved ,anterior overbite and override recovered in 13 cases ;While in group B ,crossbite was relieved, anterior overbite and override recovered in all 16 cases. （2）After the treatment, SNA, Ptm-A, ANB, Wits, U1 -SN, ANS-Me, FH-MP increased significantly in both groups （P 〈 0.05 ）. Wits, ANS-Me, FH-MP in group A increased more significantly when compared with group B （P 〈 0.05）. The increase of UI-SN and the decrease of SN-PP and L1-MP in group B changed more significantly as compared with group A. Conclusion The maxillary protraction, with or without rapid ex- pansion, can obtain significant effect in the treatment of skeletal Class Ⅲ malocclusion. The combined treatment can re- duce the labial axial inclination of anterior teeth, and mandibular counterclockwise rotation.