title: Cephalometric evaluation of symmetric and asymmetric extraction treatment for patients with Class II subdivision malocclusions.
abstract: BACKGROUND
  The purpose of this study was to cephalometrically compare the dentoskeletal and soft-tissue changes consequent to orthodontic treatment in patients with Class II subdivision malocclusion treated with asymmetric and symmetric extractions.
  
  
  METHODS
  The sample included 54 patients with Class II subdivision malocclusion and full complement of permanent teeth, including first molars, at the beginning of treatment. Patients in group 1 (n = 27) were treated with the asymmetric extraction of 3 premolars and had initial and final mean ages of 14.07 and 16.71 years. Patients in group 2 (n = 27) were treated with the symmetric extraction of 4 premolars and had initial and final mean ages of 13.35 and 15.75 years. Lateral cephalometric radiographs were taken at pretreatment and posttreatment. T tests were used to compare the groups at pretreatment and the treatment changes between groups.
  
  
  RESULTS
  The results demonstrated that the asymmetric extraction group had significantly less mandibular incisor retraction, less soft-tissue retraction, and greater increases in mandibular incisor extrusion and mandibular molar asymmetry index than the symmetric extraction group.
  
  
  CONCLUSIONS
  It was concluded that the 3-premolar asymmetric extraction protocol in Class II subdivision malocclusions produces significantly less mandibular incisor and soft-tissue retraction than the 4-premolar extraction protocol.
authors.affiliation: Department of Orthodontics, Bauru Dental School, University of São Paulo, Brazil. jansong@travelnet.com.br
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
authors.forename: Paulo Eduardo Guedes
authors.initials: PE
authors.lastname: Carvalho
authors.forename: Rodrigo Hermont
authors.initials: RH
authors.lastname: Cançado
authors.forename: Marcos Roberto
authors.initials: MR
authors.lastname: de Freitas
authors.forename: José Fernando Castanha
authors.initials: JF
authors.lastname: Henriques
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000601:surgery; D002508:Cephalometry; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D009971:Orthodontics, Corrective / Q000379:methods* / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014081:Tooth Extraction; D016896:Treatment Outcome