title: [Comparison of extraction versus non-extraction orthodontic treatment results--a preliminary study].
abstract: OBJECTIVE
  The purpose of this study was to make a comparison between extraction and non-extraction orthodontic treatment results concerning teeth alignment, occlusal relation, facial profile and treatment interval.
  
  
  METHODS
  39 extraction-non-extraction borderline cases were selected by 5 orthodontic specialists through reviewing their pre-treatment records. 5 specialists were then asked to rank the results by marking the post-treatment record of each case. And then the samples were divided into different groups according to extraction, non-extraction and extraction pattern by reviewing case history.
  
  
  RESULTS
  No statistically significant difference was found in teeth alignment, overbite and overjet, midline symmetry, lateral occlusal relation and treatment intervals. However, the post-treatment facial profile of extraction groups obtained higher marks from 5 specialists (P = 0.001).
  
  
  CONCLUSIONS
  While both extraction and non-extraction treatment can achieve comparable results in teeth alignment and occlusal relation with equivalent time interval in borderline cases, extraction treatment, whatever extraction of four first premolars or second premolars is performed, can achieve better facial profile.
authors.affiliation: Department of Orthodontics, School of Stomatology, Peking University, Beijing 100081, China.
authors.forename: Tianmin
authors.initials: T
authors.lastname: Xu
authors.forename: Minzhi
authors.initials: M
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
mesh_terms: D002648:Child; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D007574:Jaw Relation Record; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D009971:Orthodontics, Corrective / Q000379:methods*; D012189:Retrospective Studies; D014081:Tooth Extraction