Comparison of anterior crowding relapse tendency in patients treated with incisor extraction, premolar extraction, and nonextraction treatment

Abstract

Background and aimRelapse of incisor crowding is usually a serious challenge for orthodontists, and achieving long-term stable occlusion after treatment is one of the primary goals of orthodontic treatment. Stability of aligned incisors is unpredictable, and the difference is attributed to the type of malocclusion, treatment procedures, patient co-operation, or soft tissue growth and adaptability. Considering controversies in this issue, this study is aimed to compare various treatment plans used for incisor alignment in order to find the most useful one, which achieves long-term stability. MethodsThe study included 120 study casts from 40 patients with the mean age of 23.1 years and range of 15 to 38 years. The patients were treated with either nonextraction, single extraction, or premolar extraction and were evaluated at three time points, including T1 (before treatment), T2 (after treatment), and T3 (after retention). ResultsRelapse were observed in all three groups. The mean of mandibular incisor irregularity index was 0.37 ± 0.31, 0.37 ± 0.41, and 0.51 ± 0.47 in the nonextraction, premolar extraction, and incisor extraction groups, respectively. One-way analysis of variance suggested that there was no significant difference among the three groups in this regard (P = 0.2). ConclusionsGiven the results of this study, it appears that treatment modality in terms of extraction or nonextraction is not a major determinant in posttreatment relapse.