Canut J A
University of Valencia, Spain.
Eur J Orthod. 1996 Oct;18(5):485-9. doi: 10.1093/ejo/18.5.485.
The extraction of a lower incisor constitutes a therapeutic alternative limited to certain occlusal situations, i.e. supernumerary incisors, tooth size anomalies (peg-shaped upper laterals), ectopic eruption and anterior crossbites. The effect of the extraction of a single incisor on the out of retention alignment of lower anterior teeth was studied in 26 treated cases. Initial (T1), final (T2) and 5-8 years out of retention (T3) dental casts were measured. Mean crowding at the start of treatment (T1 = 3.86 mm) relapsed out of retention (T3 = 1.49 mm), with a net mean improvement of 2.37 mm. Little's irregularity index at the start of treatment (T1 = 6.44) relapsed out of retention (T3 = 2.53), with a net mean improvement of T1-T3 = 3.91. Alignment stability seems to be better than that achieved in cases subjected to premolar extraction.
拔除下前牙是一种治疗选择，仅适用于某些咬合情况，即多生牙、牙齿大小异常（上颌侧切牙呈钉状）、异位萌出和前牙反合。在26例接受治疗的病例中，研究了拔除单颗前牙对下前牙保持后排列的影响。测量了治疗开始时（T1）、结束时（T2）以及保持后5 - 8年（T3）的牙模。治疗开始时的平均牙列拥挤度（T1 = 3.86 mm）在保持后复发（T3 = 1.49 mm），平均净改善为2.37 mm。治疗开始时的Little不规则指数（T1 = 6.44）在保持后复发（T3 = 2.53），T1 - T3的平均净改善为3.91。排列稳定性似乎优于拔除前磨牙的病例。
