University of Valencia, Valencia, Spain.
Med Oral Patol Oral Cir Bucal. 2011 Mar 1;16(2):e245-51.
Although there are numerous studies in the literature on alignment stability in the lower arch, there are few referring to the upper arch.
To assess upper arch stability (irregularity index, widths and length of arch, overjet and overbite) in orthodontically treated patients by comparing late incisor stability with the initial malocclusion and type pf treatment undertaken.
The study models of 51 patients, treated with or without extractions, were analysed at three different points in time: pre-treatment (T1), post-treatment (T2) and post-retention (T3) (average 5 years). The following parameters were measured: irregularity index, arch length, inter-canine and inter-molar widths, overjet and overbite.
The results showed that upper incisor crowding relapses, although a net improvement is noted in comparison to the initial state both in cases treated with or without extractions. The arch length also relapses in both cases. The inter-canine and inter-molar widths as well as the overjet and overbite are stable in the long term. The long-term response of maxillary incisor alignment is unpredictable.
There is a statistically significant reduction in incisor irregularity, length and width of arch (inter-canine and inter-molar widths), whereas overjet and overbite undergo a reduction of little magnitude. No statistically significant correlation is noted between late incisor stability and the initial malocclusion or type of treatment.
尽管文献中有许多关于下牙弓的排列稳定性的研究，但很少有涉及上牙弓的研究。
通过比较晚期切牙稳定性与初始错颌畸形和所采用的治疗类型，评估正畸治疗患者的上牙弓稳定性（不调指数、牙弓宽度和长度、覆𬌗和覆盖）。
本研究对 51 名接受或不接受拔牙治疗的患者的研究模型在三个不同时间点（治疗前（T1）、治疗后（T2）和治疗后保持（T3））进行了分析（平均 5 年）。测量了以下参数：不调指数、牙弓长度、尖牙间和磨牙间宽度、覆𬌗和覆盖。
结果显示，上颌切牙拥挤复发，尽管与初始状态相比，无论是否拔牙治疗，都有明显的改善。牙弓长度在两种情况下也会复发。尖牙间和磨牙间宽度以及覆𬌗和覆盖在长期内是稳定的。上颌切牙排列的长期反应是不可预测的。
切牙不调、牙弓长度和宽度（尖牙间和磨牙间宽度）有统计学意义的降低，而覆𬌗和覆盖有较小程度的降低。晚期切牙稳定性与初始错颌畸形或治疗类型之间没有统计学上的显著相关性。
