title: Effects of Glide Path on the Centering Ability and Preparation Time of Two Reciprocating Instruments.
abstract: BACKGROUND
  The aim of this in vitro study was to evaluate the effects of establishing glide path on the centering ability and preparation time of two single-file reciprocating systems in mesial root canals of mandibular molars.
  
  
  METHODS
  Sixty extracted mandibular molars with curvatures of 25-39 degrees and separate foramina for the mesiobuccal and mesiolingual canals, were divided into four groups (n=15); WaveOne+glide path; WaveOne; Reciproc+glide path and Reciproc. Non-patent canals were excluded and only one canal in each tooth was instrumented. A manual glide path was established in first and third groups with #10, 15 and 20 hand K-files. Preparation was performed with reciprocating in-and-out motion, with a 3-4 mm amplitude and slight apical pressure. Initial and final radiographs were taken to analyze the amount of dentin removed in the instrumented canals. The radiographs were superimposed with an image editing software and examined to assess discrepancies at 3-, 6- and 9-mm distances from the apex. The Kruskal-Wallis test was used for statistical analysis. The level of significance was set at 0.05.
  
  
  RESULTS
  Preparation in groups without glide paths was swifter than the other groups (P=0.001). However, no difference was observed regarding centering ability.
  
  
  CONCLUSIONS
  Establishing a glide path increased the total instrumentation time for preparing curved canals with WaveOne and Reciproc instruments. Glide path had no influence on the centering ability of these systems.
authors: Department of Endodontics, Centro de Pesquisa Odontológica, Faculdade de Odontologia São Leopoldo Mandic, Campinas, SP, Brazil.
authors: Marcelo Santos
authors: MS
authors: Coelho
authors: Department of Endodontics, Centro de Pesquisa Odontológica, Faculdade de Odontologia São Leopoldo Mandic, Campinas, SP, Brazil.
authors: Carlos Eduardo
authors: CE
authors: Fontana
authors: Department of Endodontics, Centro de Pesquisa Odontológica, Faculdade de Odontologia São Leopoldo Mandic, Campinas, SP, Brazil.
authors: Augusto Shoji
authors: AS
authors: Kato
authors: Department of Endodontics, Centro de Pesquisa Odontológica, Faculdade de Odontologia São Leopoldo Mandic, Campinas, SP, Brazil.
authors: Alexandre Sigrist
authors: AS
authors: de Martin
authors: Department of Endodontics, Centro de Pesquisa Odontológica, Faculdade de Odontologia São Leopoldo Mandic, Campinas, SP, Brazil.
authors: Carlos Eduardo
authors: CE
authors: da Silveira Bueno
keywords: Centering Ability; Glide Path; Reciproc; Root Canal Preparation; Single-File Instrumentation; WaveOne