title: Postretention relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction.
abstract: Treatment stability is one of the most important objectives in orthodontics, but, despite decades of research, it is still agreed that the stability of aligned teeth is variable and largely unpredictable. This study aimed to evaluate the relapse of mandibular anterior crowding in patients treated without mandibular premolar extraction. The sample comprised 40 patients of both sexes with Class I or II malocclusions who received nonextraction treatment in the mandibular arch with edgewise mechanics. Lateral cephalograms and dental casts of each patient were obtained at pretreament, posttreatment, and 5 years postretention. Relapse of mandibular anterior crowding was assessed, and associations between this relapse and other clinical factors were also investigated. Mandibular anterior crowding was measured by the Little irregularity index, and the data were evaluated by the Mann-Whitney test. The mean relapse of mandibular anterior crowding was 1.95 mm (26.54%) over the long term. No clinical factor studied was predictive of crowding relapse in the long term.
authors.affiliation: Department of Orthodontics, Bauru Dental School, University of São Paulo, Alameda Octávio Pinheiro Brisolla 9-75, Bauru, São Paulo 17012-901, Brazil. bst00111@uol.com.br
authors.forename: Karina M S
authors.initials: KM
authors.lastname: Freitas
authors.forename: Marcos Roberto
authors.initials: MR
authors.lastname: de Freitas
authors.forename: José Fernando Castanha
authors.initials: JF
authors.lastname: Henriques
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Pinzan
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
mesh_terms: D001641:Bicuspid / Q000601:surgery; D002508:Cephalometry; D003724:Dental Arch / Q000033:anatomy & histology*; D006801:Humans; D008310:Malocclusion / Q000628:therapy; D008311:Malocclusion, Angle Class I / Q000628:therapy*; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible; D008953:Models, Anatomic; D003765:Models, Dental; D009971:Orthodontics, Corrective / Q000379:methods*; D011237:Predictive Value of Tests; D012008:Recurrence; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013223:Statistics as Topic; D014081:Tooth Extraction; D016896:Treatment Outcome