Moussa R, O'Reilly M T, Close J M
Department of Orthodontics, Baath University, Pittsburgh, Pa, USA.
Am J Orthod Dentofacial Orthop. 1995 Nov;108(5):478-88. doi: 10.1016/s0889-5406(95)70048-x.
Previous studies on long-term stability of orthodontic treatment primarily have focused on the stability of the lower arch treated with edgewise appliances. The aim of this study was to evaluate the long-term stability of the upper and the lower dental arches of patients treated with a rapid palatal expander. The sample comprised of 165 dental casts randomly selected from patients who had been out of retention for 8 to 10 years at a mean age of 30 years. Measurements were made directly on dental casts obtained at the three time intervals: before treatment, after treatment, and after retention. Differences over time between the upper and the lower dental arches and between intervals were analyzed by a two-way multivariate analysis of variance (MANOVA) and post hoc Bonferroni t tests. Differences between after treatment and after retention were statistically significant (P < 0.006) for all except lower intermolar width. However, only for lower and upper arch lengths and perimeters were the differences greater than 2.0 mm. Treatment with the rapid palatal expander presented good stability for upper intercanine width, upper and lower intermolar widths and incisor irregularity. Lower intercanine, arch length, and perimeter presented poor stability.
以往关于正畸治疗长期稳定性的研究主要集中在使用方丝弓矫治器治疗的下牙弓的稳定性上。本研究的目的是评估使用快速腭开展器治疗的患者上、下牙弓的长期稳定性。样本包括从平均年龄30岁、已保持8至10年的患者中随机选取的165副牙模。直接在三个时间点获取的牙模上进行测量：治疗前、治疗后和保持后。通过双向多变量方差分析（MANOVA）和事后Bonferroni t检验分析上、下牙弓之间以及各时间间隔之间随时间的差异。除下颌磨牙间宽度外，治疗后与保持后的差异在所有指标上均具有统计学意义（P < 0.006）。然而，只有下颌和上颌牙弓长度及周长的差异大于2.0毫米。快速腭开展器治疗在上颌尖牙间宽度、上、下颌磨牙间宽度及切牙不齐方面表现出良好的稳定性。下颌尖牙间、牙弓长度及周长表现出较差的稳定性。
