title: Orthodontic treatment time in 2- and 4-premolar-extraction protocols.
abstract: BACKGROUND
  The purpose of this study was to compare the treatment times of complete Class II malocclusions treated with 2- and 4-premolar-extraction protocols.
  
  
  METHODS
  Ninety-seven patients were selected and divided into 2 groups, according to the 2 extraction criteria. Group 1, treated with 2 maxillary premolar extractions, consisted of 49 patients (30 male, 19 female) with a mean age of 14.35 years. Group 2, treated with 4 premolar extractions, consisted of 48 patients (27 male, 21 female) with a mean age of 13.03 years. Treatment times of the groups were compared with the t test.
  
  
  RESULTS
  Treatment times were significantly shorter with the 2-premolar-extraction protocol compared with the 4-premolar-extraction protocol.
  
  
  CONCLUSIONS
  Treatment time will be shorter and the occlusal results more predictable with a 2-premolar-extraction protocol compared with 4 premolar extractions.
authors: Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil. jansong@travelnet.com.br
authors: Guilherme
authors: G
authors: Janson
authors: Fábio Rogério Torres
authors: FR
authors: Maria
authors: Sérgio Estelita Cavalcante
authors: SE
authors: Barros
authors: Marcos Roberto de
authors: MR
authors: Freitas
authors: José Fernando Castanha
authors: JF
authors: Henriques