Vasilakou Nefeli, Araujo Eustaquio A, Kim Ki Beom, Oliver Donald R
Orthodontic resident, Department of Orthodontics, Saint Louis University, St. Louis, Mo.
Professor, Department of Orthodontics, Saint Louis University, St. Louis, Mo.
Am J Orthod Dentofacial Orthop. 2016 Dec;150(6):997-1004. doi: 10.1016/j.ajodo.2016.05.012.
This retrospective study included a sample of 300 randomly selected patients from the archived records of Saint Louis University's graduate orthodontic clinic, St. Louis, Mo, from 1990 to 2012. The objective of this study was to quantify the changes obtained in phase 1 of orthodontic treatment and determine how much improvement, if any, has occurred before the initiation of the second phase.
For the purpose of this study, prephase 1 and prephase 2 records of 300 subjects were gathered. All were measured using the American Board of Ortodontics Discrepancy Index (DI), and a score was given for each phase. The difference of the 2 scores indicated the quantitative change of the complexity of the treatment. Paired t tests were used to compare the scores. Additionally, the sample was categorized into 3 groups according to the Angle classifications, and the same statistics were used to identify significant changes between the 2 scores. Analysis of variance was applied to compare the 3 groups and determine which had the most change. Percentages of change were calculated for the significant scores.
The total DI score overall and the scores of all 3 groups were significantly reduced from before to after phase 1. Overall, 42% improvement was observed. The Class I group showed 49.3% improvement, the Class II group 34.5% and the Class III group 58.5%. Most components of the DI improved significantly, but a few showed negative changes.
Significant reductions of DI scores were observed in the total sample and in all Angle classification groups. This indicates that early treatment reduces the complexity of the malocclusions. Only 2 components of the DI showed statistically significant negative changes.
这项回顾性研究从密苏里州圣路易斯市圣路易斯大学研究生正畸诊所1990年至2012年的存档记录中随机抽取了300名患者作为样本。本研究的目的是量化正畸治疗第一阶段所取得的变化，并确定在第二阶段开始之前是否有任何改善以及改善程度如何。
为了本研究的目的，收集了300名受试者第一阶段前和第二阶段前的记录。所有记录均使用美国正畸委员会差异指数（DI）进行测量，并为每个阶段给出一个分数。两个分数的差值表明了治疗复杂性的定量变化。采用配对t检验来比较分数。此外，根据安氏分类将样本分为3组，并使用相同的统计方法来确定两个分数之间的显著变化。应用方差分析来比较这3组，并确定哪一组变化最大。计算显著分数的变化百分比。
从第一阶段前到第一阶段后，总体DI总分以及所有3组的分数均显著降低。总体而言，观察到改善了42%。安氏I类组显示改善了49.3%，安氏II类组为34.5%，安氏III类组为58.5%。DI的大多数组成部分有显著改善，但有一些显示出负向变化。
在总样本和所有安氏分类组中均观察到DI分数显著降低。这表明早期治疗降低了错牙合畸形的复杂性。DI中只有2个组成部分显示出具有统计学意义的负向变化。
