title: Transverse implications of maxillary premolar extraction in Class III presurgical orthodontic treatment.
abstract: BACKGROUND
  Maxillary premolars are often extracted to resolve incisor proclination in presurgical orthodontic treatment for severe skeletal Class III patients. The aim of this article was to compare arch-width changes and orthodontic tooth movements between maxillary premolar extraction and nonextraction modalities, and to provide an additional indication for presurgical maxillary premolar extraction according to the transverse dental arch characteristics of Class III surgical-orthodontic patients.
  
  
  METHODS
  Pretreatment and posttreatment dental casts of 55 adult Class III patients (24 nonextraction, 31 extraction) who underwent surgical-orthodontic treatment were collected. The changes in maxillary and mandibular dental arch widths were measured from the canines to the second molars. Orthodontic tooth movement was evaluated with an angulation-and-inclination measuring gauge.
  
  
  RESULTS
  Statistical analyses showed that intermaxillary arch congruity was attributed mainly to maxillary arch-width changes. The arch-width changes could be interpreted as the result of inclination changes in both posterior dentitions. For the arch-width change, analysis of covariance (ANCOVA) showed a significant extraction effect: the premolar extraction group's ability to accommodate arch-width change was significantly greater than that of the nonextraction group.
  
  
  CONCLUSIONS
  The indications for maxillary premolar extraction in Class III presurgical orthodontic treatment might depend in part on the characteristics of the maxillary arch width and posterior teeth inclinations.
authors.affiliation: Department of Orthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, South Korea.
authors.forename: Shin-Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Tae-Woo
authors.initials: TW
authors.lastname: Kim
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Nahm
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001641:Bicuspid / Q000601:surgery; D002508:Cephalometry; D003724:Dental Arch / Q000033:anatomy & histology; D006801:Humans; D008313:Malocclusion, Angle Class III / Q000628:therapy*; D008437:Maxilla; D003765:Models, Dental; D009971:Orthodontics, Corrective / Q000379:methods*; D019340:Osteotomy, Le Fort; D011300:Preoperative Care; D012044:Regression Analysis; D014081:Tooth Extraction