title: Frequency of orthodontic extraction.
abstract: BACKGROUND
  The option of dental extraction for orthodontic purposes has been debated for more than 100 years, including periods when it was widely used in treatment, including the present, during which other methods are used to avoid dental extractions. The objective was to analyze the frequency of tooth extraction treatment performed between 1980 and 2011 at the Orthodontic Clinic of Universidade Estadual do Rio de Janeiro (UERJ).
  
  
  METHODS
  The clinical records of 1484 patients undergoing orthodontic treatment were evaluated. The frequency of extractions was evaluated with regard to sex, Angle's classification, the different combinations of extractions and the period when orthodontic treatment began. Chi-square test was used to determine correlations between variables, while the chi-square test for trends was used to assess the frequency of extractions over the years.
  
  
  RESULTS
  There was a reduction of approximately 20% in the frequency of cases treated with tooth extraction over the last 32 years. The most frequently extracted teeth were first premolars. Patients with Class I malocclusion showed fewer extractions, while Class II patients underwent a higher number of extraction treatment. There were no statistically significant differences with regard to sex.
  
  
  CONCLUSIONS
  New features introduced into the orthodontic clinic and new esthetic concepts contributed to reducing the number of cases treated with dental extractions. However, dental extractions for orthodontic purposes are still well indicated in certain cases.
authors.affiliation: Department of Orthodontics, Universidade Estadual do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Camila de S
authors.initials: Cde S
authors.lastname: Dardengo
authors.affiliation: Department of Orthodontics, Universidade Estadual do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Luciana Q P
authors.initials: LQ
authors.lastname: Fernandes
authors.affiliation: Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Jonas
authors.initials: J
authors.lastname: Capelli Júnior
mesh_terms: D001641:Bicuspid; D006801:Humans; D008310:Malocclusion / Q000628:therapy; D014081:Tooth Extraction