title: Comparison Between the Accuracy of NovApex Apex Locator and Radiographs in Determining Radiographic Apex.
abstract: BACKGROUND
  Determination of the canal working length with radiographs has many drawbacks. Electronic apex locators have been developed to overcome some of these problems. Recently, a newly designed apex locator called NovApex has been introduced. All the studies conducted to determine the accuracy of NovApex have been carried out in-vitro on extracted teeth. The aim of this in vivo study was to evaluate the accuracy of NovApex compared with traditional radiographic method.
  
  
  METHODS
  Twenty-five patients whose lower molars that were candidates for extraction were selected. The teeth were accessed, and the radiographic working length was determined by measuring the length of the initial file 0.5mm short of the radiographic apex. Then, NovApex apex locator was used to measure the electronic working length. Subsequently, the tooth was extracted, and the actual working length was measured by introducing a size #15 K-file into each canal until the file tip was visible at the apex, then 1.5mm was subtracted to attain the working length. Cohen's Kappa was computed for each of the methods versus actual working length as a measure of reliability. The accuracies were compared using Chi-square test.
  
  
  RESULTS
  The accuracy of NovApex apex locator and radiographic method in detecting the apical end point within ±0.5mm was 74.7% and 68%, respectively; this was not significantly different (P<0.001).
  
  
  CONCLUSIONS
  The NovApex apex locator is useful in detecting the apical end point with the accuracy similar to radiographic method. However, neither technique is fully reliable in detecting the apical end point of the canal.
authors.affiliation: Department of Endodontics, Dental and periodontal disease research center, Dental School, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Shahriar
authors.initials: S
authors.lastname: Shahi
authors.forename: Saeed
authors.initials: S
authors.lastname: Rahimi
authors.forename: Amin Salem
authors.initials: AS
authors.lastname: Milani
authors.forename: Mohammad
authors.initials: M
authors.lastname: Asghari Jafarabadi
authors.forename: Gholam Reza
authors.initials: GR
authors.lastname: Djoorabbaf Naghsh
keywords: Electronic Apex Locator; NovApex; Radiographic Image Interpretation