Angle Orthod. 2023 Nov 1;93(6):652-658. doi: 10.2319/101722-722.1.
To evaluate whether the quality of orthodontic finishing influences long-term stability of anterior tooth alignment.
This retrospective study evaluated 38 patients. Data were obtained at the beginning of treatment (T0), at the end (T1), and at least 5 years after T1 (T2). At this point, the individuals were no longer wearing retainers. Anterior tooth alignment was measured using Little's index (LI). Effect on alignment stability was tested with multiple linear regression using LI-T0, LI-T1, intercanine width difference T1-T0, overbite (T1), overjet (T1), age, gender, time without retention, and presence of third molars as predictor variables. Well-aligned (LI < 1.5 mm) and misaligned (LI > 1.5 mm) cases were compared at T2.
At T2, the alignment stability in the upper arch was inversely associated with the alignment quality (R2 = 0.378, P < .001) and directly associated with overbite (R2 = 0.113, P = .008) at T1. Posttreatment changes caused cases finished with poor alignment to become similar to those finished with excellent alignment (P = .917). In the mandible, posttreatment changes were directly associated only with overjet (R2 = 0.152, P = .015) and well-finished cases displayed better alignment than poorly finished cases (P = .011). Other variables showed no significant association.
In arches without retention, better quality of orthodontic finishing does not guarantee the stability of anterior alignment. In the maxilla, long-term changes were more significant the greater the overbite and the better the quality of alignment at end of treatment. In the mandible, changes were not dependent on the quality of finishing but were associated with greater overbite at T2.
评估正畸完成质量是否影响前牙排列的长期稳定性。
本回顾性研究共纳入 38 名患者。资料采集时间分别为治疗开始时（T0）、结束时（T1）以及 T1 后至少 5 年（T2），此时患者已不再佩戴保持器。采用 Little 指数（LI）测量前牙排列情况。采用多元线性回归，以 LI-T0、LI-T1、尖牙间宽度差 T1-T0、覆（牙合）（T1）、覆盖（T1）、年龄、性别、无保持器时间和第三磨牙存在与否为预测变量，检验对排列稳定性的影响。比较 T2 时 LI＜1.5mm 的排列整齐和 LI＞1.5mm 的排列不齐病例。
T2 时，上颌弓的排列稳定性与矫治质量呈负相关（R2=0.378，P＜0.001），与 T1 时覆（牙合）呈正相关（R2=0.113，P=0.008）。矫治后，排列不良的病例变化与排列整齐的病例相似（P=0.917）。下颌，仅与覆盖呈直接相关（R2=0.152，P=0.015），且排列整齐的病例优于排列不良的病例（P=0.011）。其他变量无显著相关性。
无保持器的牙弓中，更好的正畸完成质量并不能保证前牙排列的稳定性。在上颌，治疗结束时覆（牙合）越大和排列质量越好，长期变化越显著。在下颌，变化与完成质量无关，而与 T2 时更大的覆盖相关。
