title: Influence of different methods of cervical flaring on establishment of working length.
abstract: OBJECTIVE
  To investigate the influence of three different rotary systems for cervical flaring on establishment of the real working length.
  
  
  METHODS
  Thirty mandibular first molars were submitted to conventional endodontic access and initial working length measurement, followed by irrigation/suction of the pulp chamber with 5% sodium hypochlorite. Teeth were randomly divided into 3 groups (n=10) and cervical flaring of the mesiobuccal canals were performed using one of the following instrument systems: Group 1 - Gates-Glidden burs; Group 2 - Orifice Openers; Group 3 - La Axxess system. Two subsequent numbers of instruments of each rotary system were used and the final working length was recorded. A digital calyper was used to record the working length, in millimeters, to investigate a possible discrepancy between initial and final measurements.
  
  
  RESULTS
  Analysis of variance (Anova) na Tukey test revealed statistical difference between Group 1 and Groups 2 and 3 (p pound 0.05).
  
  
  CONCLUSIONS
  All groups presented shorter working length after cervical flaring; groups prepared with instruments La Axxes and Orifice Opener presented the best results among the systems studied.
authors.affiliation: University of Passo Fundo - FO-UPF.
authors.forename: Dieison Nardi
authors.initials: DN
authors.lastname: Lazzaretti
authors.forename: Bernardo Alievi
authors.initials: BA
authors.lastname: Camargo
authors.forename: Alvaro
authors.initials: A
authors.lastname: Della Bona
authors.forename: Volmir João
authors.initials: VJ
authors.lastname: Fornari
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Vanni
authors.forename: Flares
authors.initials: F
authors.lastname: Baratto Filho