title: A comparative evaluation of working length with digital radiography and third generation apex locator (ProPex) in the presence of various intracanal irrigants: An in vivo/ex vivo study.
abstract: BACKGROUND
  Accurate working length determination is a pre-requisite for a successful endodontic treatment. Even with improved systems of working length measurement, different readings may be recorded in different electrolytes present in the canal. The purpose of this in vivo/ex vivo comparative study was to determine the accuracy in measuring the working length of root canal using Direct Digital Radiographic Method (Radiovisiography or RVG) and ProPex electronic apex locator in the presence of three different irrigating solutions: 0.9% normal saline, 2% chlorhexidine, 3% NaOCl solutions.
  
  
  METHODS
  Forty single-rooted human teeth scheduled for extraction with mature apices were selected for this study. Measurements were performed by using RVG and ProPex in the presence of irrigating solutions. After extraction of the teeth, light microscope was used to confirm visually the relationship of the tip of the endodontic file to the apical foramen, and actual lengths were determined by reducing 0.5 mm from this length. The statistical analysis was performed by one-way ANOVA test and Tukey-HSD post hoc procedure. P < 0.05 was considered as significant.
  
  
  RESULTS
  No significant difference was found between overall mean electronic working length and digital radiographic length; however, prediction error (P < 0.05) was significant with respect to different irrigants. Among the irrigating solutions, chlorhexidine gluconate had the smallest distance to the actual lengths, whereas NaOCl had the greatest.
  
  
  CONCLUSIONS
  Electronic apex locator ProPex yielded best result in the presence of chlorhexidine, whereas the largest error was demonstrated with NaOCl indicating that higher electroconductive irrigating solutions affect the precision of multi-frequency apex locators.
authors.affiliation: Department of Dentistry, Shere Kashmir Institute of Medical Sciences, Srinagar, India.
authors.forename: Irfana
authors.initials: I
authors.lastname: Khursheed
authors.affiliation: Department of Conservative Dentistry, Swami Devi Dyal Hospital and Dental College, Panchkula, Haryana, India.
authors.forename: Ruchika
authors.initials: R
authors.lastname: Bansal
authors.affiliation: Department of Oral Medicine and Radiology, Swami Devi Dyal Hospital and Dental College, Panchkula, Haryana, India.
authors.forename: Tajinder
authors.initials: T
authors.lastname: Bansal
authors.affiliation: Department of Oral Pathology and Microbiology, Swami Devi Dyal Hospital and Dental College, Panchkula, Haryana, India.
authors.forename: Harkanwal Preet
authors.initials: HP
authors.lastname: Singh
authors.affiliation: Department of Pedodontics and Preventive Dentistry, Faculty of Dental Sciences, King George's Medical, University, Lucknow, Uttar Pradesh, India.
authors.forename: Madhulika
authors.initials: M
authors.lastname: Yadav
authors.affiliation: Department of Oral Medicine and Radiology, Sri Venkata Sai Institute of Dental Sciences, Mahabubnagar, Andhra Pradesh, India.
authors.forename: K Jetender
authors.initials: KJ
authors.lastname: Reddy
keywords: Apex locators; digital radiography; irrigation solutions; working length