Influence of the presence, congenital absence, or prior removal of third molars on recurrence of mandibular incisor crowding after orthodontic treatment: Systematic review and meta-analysis

Abstract

ObjectivesWas to seek scientific evidence that supports the causality between the presence of third molars and recurrence of mandibular incisor crowding after orthodontic treatment. MethodsA systematic search of the literature was conducted, without limitations on year of publication and language, in the following electronic databases: Scopus, PubMed, Web of Science, Medline, Embase, Cochrane, Controlled Trials and Grey Literature, in addition to manual search in the lists of references of articles included. Included in the review were clinical studies conducted with patients undergoing orthodontic post-treatment, without limitation of sex and/or age (P), who had third molars removed (I), compared with patients who were not submitted to third molar extraction (C), with the main outcome being the crowding of mandibular incisors in the orthodontic post-treatment period (O). In order to conduct the meta-analysis the primary outcomes (irregularity index, intercanine width and length of arch) were recorded as continuous variables. The data were tabulated and analyzed in the software program MedCalc - version 13.1.2.0. Results239 articles were found in the databases used. After application of the eligibility criteria and removal of duplications, only 6 articles remained. The results of the meta-analysis indicated no significant difference in the irregularity index and intercanine width in the groups with the third molar present or extracted. ConclusionThe presence of third molars had no repercussion on the irregularity index and intercanine width, thus the presence of third molars appear to exert no influence on the recurrence of crowding of mandibular incisors.