title: Changes in the soft tissue facial profile following orthodontic extractions: a geometric morphometric study.
abstract: OBJECTIVE
  The aim of this study is to test the null hypothesis that changes in soft tissue facial profile in children who undergo orthodontic treatment, using either an extraction or non-extraction technique, do not differ.
  
  
  METHODS
  Longitudinal, retrospective.
  
  
  METHODS
  San Juan, PR and Aberdeen, UK. Fifty-eight consecutively treated children using fixed appliances with a mean age of 13.2 (+/- 2.1) years.
  
  
  METHODS
  Extraction of the upper and lower, first or second premolars.
  
  
  METHODS
  The mean pre- and post-treatment, extraction and non-extraction configurations were compared using finite-element scaling analysis (FESA), incorporating a thin-plate spline interpolation.
  
  
  RESULTS
  Post-treatment the two groups differed statistically in the premaxillary region (p < 0.05) with the non-extraction group being relatively larger in that region by 25%. For the non-extraction group after treatment, localized increases in relative size in the naso-maxillary region size of 25% (p < 0.01) were present. For the extraction group after treatment, a non-significant reduction in relative size of 15% was localized in the putative bicuspid area.
  
  
  CONCLUSIONS
  Soft tissue facial differences in non-extraction and extraction cases prior to treatment may be accentuated following orthodontic treatments that elect non-extraction or extraction protocols. Robust diagnosis and treatment planning, incorporating the judicious use of extractions if appropriate, may yield optimal orthodontic outcomes.
authors.affiliation: Center for Craniofacial Disorders, School of Medicine, University of Puerto Rico, San Juan, PR 00936-5067, USA. gdsingh@rcm.upr.edu
authors.forename: G D
authors.initials: GD
authors.lastname: Singh
authors.forename: Linette
authors.initials: L
authors.lastname: Maldonado
authors.forename: B S
authors.initials: BS
authors.lastname: Thind
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000601:surgery; D002508:Cephalometry; D002648:Child; D003799:Dental Stress Analysis; D005145:Face / Q000033:anatomy & histology*; D020342:Finite Element Analysis; D006801:Humans; D008137:Longitudinal Studies; D009971:Orthodontics, Corrective / Q000379:methods*; D025341:Principal Component Analysis; D012189:Retrospective Studies; D014081:Tooth Extraction