Indiana University, Indianapolis, USA.
Angle Orthod. 2011 Mar;81(2):192-7. doi: 10.2319/062210-341.1.
To test the hypothesis that there is no relationship between the components of the American Board of Orthodontics (ABO) discrepancy index (DI) and duration of orthodontic treatment.
A retrospective review of 732 patient records with permanent dentition was performed. Pretreatment radiographs and casts were used to determine the DI score. Other data collected were total treatment duration, age, sex, ethnicity, and the date fixed appliances were removed. Reliability tests showed substantial agreement between examiners (Cohen's kappa 0.68-0.94). Pearson and Spearman correlation coefficients were used to assess the association between the DI scores and length of treatment. A multiple variable regression analysis was used to determine which variables predict treatment duration (P < .05 significant).
There was a significant association between the DI and treatment duration. There was a significant multivariate association for DI components (occlusions, crowding, overjet, cephalometrics, overbite, lateral open bite, and tooth transposition) and treatment duration.
The hypothesis was rejected. This retrospective study of university clinical records showed that the average increase in treatment duration was about 11 days for each point increase in total DI score. Treatment duration was differentially increased by various components of the DI: approximately 6.5 months for tooth transposition; approximately 1 month for crowding, overjet, or overbite; approximately 3 weeks for occlusion discrepancies; approximately 2 weeks for lateral open bite; and approximately 5 days for cephalometric discrepancies.
验证美国正畸委员会（ABO）错𬌗指数（DI）各组成部分与正畸治疗时间之间无相关性的假设。
对 732 例恒牙列患者的病历进行回顾性研究。使用治疗前的 X 光片和模型来确定 DI 评分。收集的其他数据包括总治疗时间、年龄、性别、种族以及固定矫治器去除的日期。可靠性检验显示检查者之间存在高度一致性（Cohen's kappa 0.68-0.94）。Pearson 和 Spearman 相关系数用于评估 DI 评分与治疗时间之间的关联。多元回归分析用于确定哪些变量可预测治疗时间（P<0.05 为显著）。
DI 与治疗时间之间存在显著相关性。DI 各组成部分（错𬌗、拥挤、覆𬌗、头影测量、覆盖、侧方开𬌗和牙齿错位）与治疗时间之间存在显著的多元相关性。
该假设被否定。这项对大学临床记录的回顾性研究表明，总 DI 评分每增加 1 分，治疗时间平均增加约 11 天。DI 的各个组成部分对治疗时间的影响程度不同：牙齿错位约增加 6.5 个月；拥挤、覆𬌗或覆盖约增加 1 个月；咬合错位约增加 3 周；侧方开𬌗约增加 2 周；头影测量错位约增加 2 周；约增加 5 天。
