颈牵引装置矫治替牙期安氏Ⅱ类1分类错矫治时机的临床探讨

A study on the extraoral cervical traction in the treatment of skeletal ClassⅡdivision 1 malocclusion in mixed dentition

目的:比较替牙早期及替牙晚期骨性安氏Ⅱ类1分类错行口外颈牵引治疗的疗效,探讨合适的矫治时机。方法:样本包括11例替牙早期患者及15例替牙晚期患者,均为骨性安氏Ⅱ类1分类错牙合,ANB≥5°,分别予以口外颈牵引治疗。治疗前后摄取X线头颅侧位定位片,进行头影测量及统计学分析。2组治疗前后比较采用配对t检验,2组之间采用团体t检验。结果:2组上颌骨生长均受到了抑制,SNA角、上颌骨长度(A-Ptm)及ANB角均有减小。U1-SN角减小,上前牙前突得到改善。2组比较,替牙晚期组变化更明显,2组之间有显著性差异(P<0.01)。而上颌第1恒磨牙远移距离在2组间则无显著性差异(P<0.01)。结论:在替牙晚期对骨性安氏Ⅱ类1分类错患者行口外颈牵引治疗较为合适,有利于恒牙期的二期矫正治疗。

PURPOSE:To evaluate the effects of extraoral cervical traction on skeletal Class Ⅱ division 1 malocclusion of early or late mixed dentition and discuss the optimal treatment timing. METHODS: The sample consisted of two groups of skeletal Class Ⅱ division 1 malocclusion. One group with 11 cases was treated started in early mixed dentition while the other with 15 cases in late mixed dentition. All cases were treated with extraoral cervical traction headgear. Cephalometric analysis was conducted to evaluate the treatment effects. Student's t test was applied for statistical analysis. RESULTS: SNA, ANB and the length of maxilla (A-Ptm) were reduced and the inclination of maxillary incisor was decreased in both two groups. When comparing the two groups, it was found that the reduction of SNA was more notable, which means the inhibition of the maxilla was more evident in late mixed dentition. The difference was statistically significant(P<0.01). There was no significant difference on the distalization of the first upper molar between two groups(P<0.01). CONCLUSIONS: The extraoral cervical traction might be more effective in late mixed dentition to restrain maxillary growth in the treatment of skeletal Class Ⅱ division 1 malocclusion.