Liu Yan, Xu Tian-min, Lin Jiu-xiang
Department of Orthodontics, Peking University School of Stomatology, Beijing 100081, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2003 Sep;38(5):381-3.
To investigate the relapse of incisor alignment after orthodontic treatment and possible factors which may related to its stability.
72 finished cases with full records selected from orthodontic clinic of Peking University School of Stomatology composed the sample. The follow-up lateral head films and study casts were taken at least 2 years after orthodontic treatment. The cephalograms were measured by computerized program and the study casts measured by caliper.
The upper Irregularity Index decreased from (11.5 +/- 5.02) mm before treatment to (2.01 +/- 1.39) mm after treatment and then increased to (3.46 +/- 1.69) mm in the follow-up stage. The lower Irregularity Index decreased from (7.24 +/- 44.35) mm before treatment to (1.75 +/- 1.04) mm after treatment and then increased to (3.39 +/- 1.78) mm in the follow-up stage. The changes are significant statistically. The changes of jaw in the sagittal and vertical directions as well as the related changes of the position of lower incisors, the decrease of the lower canine arch width, Bolton Index and sex all have statistically significant relation with the changes of the lower Irregularity Index after retention.
Compared with lower arch, the alignment in upper arch is more stable in the follow-up stage. The results suggest that some possible factors may have correlations with the change of lower arch crowding during the follow-up stage.
探讨正畸治疗后切牙排列的复发情况以及可能与其稳定性相关的因素。
从北京大学口腔医学院正畸门诊选取72例有完整记录的完成病例组成样本。正畸治疗后至少2年拍摄随访头颅侧位片和研究模型。头颅侧位片用计算机程序测量，研究模型用卡尺测量。
上牙列不整齐指数从治疗前的（11.5±5.02）mm降至治疗后的（2.01±1.39）mm，随后在随访阶段增至（3.46±1.69）mm。下牙列不整齐指数从治疗前的（7.24±44.35）mm降至治疗后的（1.75±1.04）mm，随后在随访阶段增至（3.39±1.78）mm。这些变化具有统计学意义。下颌在矢状向和垂直向的变化以及下切牙位置的相关变化、下尖牙弓宽度的减小、Bolton指数和性别与保持后下牙列不整齐指数的变化均具有统计学显著相关性。
与下牙弓相比，随访阶段上牙弓排列更稳定。结果提示一些可能因素可能与随访阶段下牙弓拥挤度的变化相关。
