title: Does the decision to extract influence the development of gingival recessions? A retrospective long-term evaluation.
abstract: OBJECTIVE
  Mandibular anterior crowding can be treated by expanding the dental arch or by extracting teeth, usually premolars. The aim of this study was to assess long-term outcomes of extraction versus non-extraction therapies in terms of gingival recession.
  
  
  METHODS
  Fifty consecutive patients were selected, including 26 non-extraction and 24 extraction cases. All had been treated with fixed appliances because of well-defined comparable moderate crowding and Angle Class I malocclusion. Patient age was documented before treatment, upon debonding, and during retention, thus, allowing the calculation of the duration of active treatment and retention. The records available for these three points in time included casts and cephalograms. The casts were used to quantify mandibular anterior crowding and the associated clinical crown lengths. Based on the cephalograms, a number of symphyseal variables were measured. Data analysis included descriptive statistics, correlation tests, and multiple regressions.
  
  
  RESULTS
  For accurate comparison of the extraction and non-extraction treatment groups, we required and verified that no significant intergroup differences were present with regard to initial crowding, duration of retention, and age at final record-taking. Both groups revealed increases in crown length, which fell short of statistical significance but were twice as large for canines than for incisors. The treatment decisions to extract premolars did result in significantly different topographic positions of the lower incisors, but they made no difference in the recession outcomes. None of the variables in our regression analysis was found to predict gingival recession.
  
  
  CONCLUSIONS
  Findings of gingival recession in patients having undergone orthodontic treatment do not seem to be related to extraction/non-extraction treatment decisions.
authors.affiliation: Department of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstr. 11, 8032, Zurich, Switzerland.
authors.forename: Nicolas M
authors.initials: NM
authors.lastname: Villard
authors.affiliation: Department of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Plattenstr. 11, 8032, Zurich, Switzerland. raphael.patcas@zzm.uzh.ch.
authors.forename: Raphael
authors.initials: R
authors.lastname: Patcas
mesh_terms: D000293:Adolescent; D015984:Causality; D002648:Child; D000066491:Clinical Decision-Making; D005260:Female; D005889:Gingival Recession / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000453:epidemiology* / Q000628:therapy*; D011183:Postoperative Complications / Q000453:epidemiology*; D019239:Practice Patterns, Dentists' / Q000706:statistics & numerical data; D011300:Preoperative Care / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology; D014081:Tooth Extraction / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Crowding; Extraction; Fixed appliance; Gingival recession; Malocclusion, Angle Class I