title: Influence of extraction and nonextraction orthodontic treatment in Japanese-Brazilians with class I and class II division 1 malocclusions.
abstract: BACKGROUND
  The primary objective of this retrospective, longitudinal, cephalometric investigation was to study the influence of extraction and nonextraction orthodontic treatment on the facial height of Japanese-Brazilian children with Class I and Class II Division 1 malocclusions.
  
  
  METHODS
  The sample included 59 mesocephalic patients distributed into 4 groups: group 1: Class I patients treated with 4 first premolar extractions; group 2: Class I patients treated nonextraction; group 3: Class II Division 1 patients treated with 4 first premolar extractions; group 4: Class II Division 1 patients treated nonextraction. The overall initial mean age of the groups was 12.14 years, and all groups were treated with standard edgewise appliances for a mean period of 2.49 years. The pretreatment and posttreatment stage comparison and the intergroup comparison of the treatment changes were conducted between extraction and nonextraction groups in the Class I and Class II malocclusion samples with t tests.
  
  
  RESULTS
  The amounts of changes in the absolute magnitude of posterior and anterior facial heights and in the ratios of lower posterior facial height/lower anterior facial height and lower anterior facial height/total anterior facial height were similar between extraction and nonextraction treatment in both Class I and Class II malocclusions.
authors.affiliation: Department of Orthodontics, Bauru Dental School, University of São Paulo, Brazil.
authors.forename: Sandra Márcia
authors.initials: SM
authors.lastname: Hayasaki
authors.forename: José Fernando
authors.initials: JF
authors.lastname: Castanha Henriques
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
authors.forename: Marcos Roberto
authors.initials: MR
authors.lastname: de Freitas
mesh_terms: D000704:Analysis of Variance; D044466:Asian People; D001641:Bicuspid / Q000601:surgery; D001938:Brazil; D002508:Cephalometry; D002648:Child; D005260:Female; D006801:Humans; D007564:Japan / Q000208:ethnology; D008137:Longitudinal Studies; D008297:Male; D008311:Malocclusion, Angle Class I / Q000628:therapy*; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008445:Maxillofacial Development; D009971:Orthodontics, Corrective / Q000379:methods*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014081:Tooth Extraction; D014716:Vertical Dimension