title: Working Length Determination Using Cone-Beam Computed Tomography, Periapical Radiography and Electronic Apex Locator in Teeth with Apical Periodontitis: A Clinical Study.
abstract: BACKGROUND
  The purpose of this clinical study was to compare the accuracy of working length (WL) determination using cone-beam computed tomography (CBCT), conventional periapical radiographies and electronic apex locator.
  
  
  METHODS
  This study was conducted during root canal treatment of 19 patients with a total of 30 single-rooted teeth diagnosed with apical periodontitis. After taking the initial parallel periapical radiographies, the initial file was advanced into the canal until the WL was detected by the apex locator. Subsequently, the WL was measured and WL radiographies were taken with the file set in the canal. Afterwards, CBCT images were acquired. These three measurements were tabulated and compared and the data were analyzed using the Friedman test. The level of significance was set at 0.05.
  
  
  RESULTS
  The mean values for WL determination by electronic apex locator, periapical radiograph and CBCT images were 22.25, 22.43 and 22.65, respectively which was not statistically significant (P>0.05).
  
  
  CONCLUSIONS
  Working length determination using CBCT images was precise when compared to radiographic method and electronic apex locator.
authors.affiliation: Dental School, Federal University of Goiás, Goiânia, GO, Brazil;
authors.forename: André Luiz Gomide
authors.initials: AL
authors.lastname: de Morais
authors.affiliation: Department of Endodontics, Federal University of Goiás, Goiânia, Go, Brazil;
authors.forename: Ana Helena Gonçalves
authors.initials: AH
authors.lastname: de Alencar
authors.affiliation: Department of Endodontics, University of Cuiabá, Cuiabá, MT, Brazil.
authors.forename: Cyntia Rodrigues de Araújo
authors.initials: CR
authors.lastname: Estrela
authors.affiliation: Department of Endodontics, Federal University of Goiás, Goiânia, Go, Brazil;
authors.forename: Daniel Almeida
authors.initials: DA
authors.lastname: Decurcio
authors.affiliation: Department of Endodontics, Federal University of Goiás, Goiânia, Go, Brazil;
authors.forename: Carlos
authors.initials: C
authors.lastname: Estrela
keywords: Apical Foramen; Cone-Beam Computed Tomography; Dental Radiography; Electronic Apex Locator; Tooth Apex