不同Z角标准对正畸矫治难度指数分布情况的影响

The influence of distinct Z Angle standard on 156 class II malocclusions with the differential diagnostic analysis of Tweed-Merrifield

目的:应用Tweed-Merrifield分析法,观察不同Z角标准对正畸矫治难度指数分布情况的影响。方法:对156例安氏II类错进行Tweed-Merrifield鉴别诊断分析,所有病例进行两次难度指数计算,第一次完全按Tweed-Merrifield标准进行计算,为Tweed-Merrifield标准组,第二次将其中的Z角标准值按傅民魁标准计算,为傅民魁标准组。比较两组在治疗难度指数分布上的差异。结果:Tweed-Merrifield标准组中,治疗难度指数轻度22例(14.10%);中度72例(46.16%);重度62例(39.74%)。傅民魁标准组中,治疗难度指数轻度33例(21.15%);中度81例(51.92%),而重度42例(26.92%)。x2检验提示二者有显著的统计学差异(P<0.05)。Tweed-Merrifield标准下,样本的Z角难度指数均值为19.01±11.49;傅民魁标准下,样本Z角难度指数均值为11.71±12.63,二者有显著的统计学差异(P<0.01)。按两种不同标准值计算得出的Z角治疗难度指数均随治疗难度的增加而增加。结论:由于人种的差异,头影测量指标的正常值范围不同,得出的治疗难度也会不同,治疗追求的目标也不完全一致。在应用Tweed-Merrifield鉴别诊断系统进行诊断分析时,总难度指数分值应与各观察单因素相结合,从而客观、准确地反映患者的颅面和牙列特征。

Objective：To observe the influence of distinct Z angle standards with the method of Tweed-Merrifield differential diagnosis. Method：156 cases of Class II were selected to analyze with Tweed-Merrifield differential diagnosis. According to the Z angle standards,the samples were divided into two groups：the Tweed -Merrifield group and the Fuminkui group. The influence of the different standards on the malocclusion were investigated. Result：There is significant divergence between the two groups（P 0.05）. In the Tweed-Merrifield group,The percentage of the mild group,the moderate group and the severe group in all samples is 14.10 %,46.16 % and 39.74 %,while the percentage of the mild group,the moderate group and the severe group in all samples is 21.15 %,51.92 % and 26.92 % in the Fuminkui group. According to the Tweed -Merrifield standard the average of the Z angle Difficulty is 19.01±11.49;while with the Fuminkui standard,the value reduced to 11.71±12.63. Also have significant divergence （P 0.01）. Conclusion：Because of the difference of race, the normal value range of measurement is distinct,the Difficulty is different as well as the aim of the treatment plan is different also. To adopt the Tweed-Merrifield differential diagnosis system,the total Difficulty should combine with each solo factor,so as to indicate the cranial-facial feature of the patient objectively and properly.