Dentoalveolar effects of nonextraction orthodontic treatment of moderate crowding: A comparison of conventional, active self-ligating, and passive self-ligating bracket systems

Abstract

ObjectiveThe purpose of this study was to compare patterns of dentoalveolar changes that take place after nonextraction treatment of Class I malocclusions with moderate crowding using conventional (CON), active self-ligating (ASL), and passive self-ligating (PSL) bracket systems. Material and MethodsThree cast and nine cephalometric variables on 39 patients were evaluated and compared before treatment (T0), at end of treatment (T1), and ≥6 months in retention (T2). The pattern of change over time points was visualized and defined as the profile formed on a graph of the measurement over time. Differences in patterns between the groups were visualized as nonparallel profiles, and detected statistically using time*group interaction terms that were included in multivariable analyses of variance. Post hoc Tukey test was used to compare estimated means between all possible paired time points within each system. ResultsPatterns of change did not differ significantly for cephalometric variables, most of the arch widths (AW), the maxillary arch perimeter (AP) (P = 0.1404), or maxillary arch depth (AD) (P = 0.2601), but did differ for the mandibular AP (P = 0.0145) and AD (P = 0.0224). ConclusionsAlthough there were no significant differences between CON and PSL in the patterns of changes for any of the variables studied, ASL showed some differences from either CON or PSL. All three groups showed statistically significant increases in AWs of maxillary or mandibular premolars. Although ASL seemed to have controlled the mandibular incisors better, the results need to be interpreted with caution, as the clinical significance of the differences seen could be limited under certain circumstances.