World Journal of Dentistry

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VOLUME 2 , ISSUE 4 ( October-December, 2011 ) > List of Articles


An in vitro Comparison of Root Canal Measurement in Permanent Teeth by Electronic Apex Locator, Conventional and Digital Radiography

Alexander, Musab Hamed Saeed, Nazil A Abtahl, A Praveen Pradeep

Citation Information : A, Saeed MH, Abtahl NA, Praveen Pradeep A. An in vitro Comparison of Root Canal Measurement in Permanent Teeth by Electronic Apex Locator, Conventional and Digital Radiography. World J Dent 2011; 2 (4):312-315.

DOI: 10.5005/jp-journals-10015-1104

Published Online: 01-12-2011

Copyright Statement:  Copyright © 2011; The Author(s).



In endodontic treatment for permanent teeth, it is important to estimate the working length precisely. Currently, various methods are used in clinical practice for working length estimation. The objective of this study is to compare the accuracy of root canal length in permanent teeth determined by electronic apex locators, conventional and digital radiography.

Materials and methods

A total of 50 single rooted permanent teeth with mature apices were extracted for periodontal reasons and obtained from different sources without caries were studied. The radiographic measurements were done using paralleling technique. Electronic measurements were done next using third generation, DentAport ZX. Actual canal length of each tooth was measured using direct observation of the apical exit of the file. Measurements obtained from radiographic and electronic methods were compared to the actual tooth length. Interclass correlation coefficients and failure rate for each method and their combinations were calculated using STATA 12.0 software.


The measurements obtained through all the three techniques showed high interclass correlation coefficients and excellent level of agreement. The failure rate of measurements obtained through conventional radiography, digital radiography and electronic apex locators was 38, 30 and 22% respectively. Combination of conventional radiography with electronic apex locator showed an accuracy of 90%, while combination of digital radiographs and electronic apex locators given an accuracy of 96%.


A combination of digital radiographic and apex locator methods for determining the root canal length in permanent teeth can be considered safe, reliable and precise.

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  1. Why canals should be filled to the dentinocemental junction. J Am Dent Assoc 1930;17:293-96.
  2. The position and topography of the apical canal constriction and apical foramen. Int Endod J 1984;17(4):8.
  3. Anatomy of the root apex and its histologic changes with age. Oral Surg Oral Med Oral Pathol 1990; 69(2):238-42.
  4. Electronic apex locators: Determining proper canal length. Parkwell online learning centre.
  5. Clinical investigation of measuring working length of root canals with an electronic device and with digital-tactile sense. J Am Dent Assoc 379-87.
  6. Effect of gloves on tactile discrimination using an endodontic model. International Endodontic Journal 1990;23:9.
  7. The ability of the radiograph to determine the location of the apical foramen. International Endodontic Journal 1991;24(1):28-35.
  8. Anatomy of the root apex and its histologic changes with age. Oral Surgery, Oral Medicine, Oral Pathology 1990;69:238-42.
  9. Apex locators in endodontics: Which, when and how? Dental Update 1994;27:328-30.
  10. Frequency of overinstrumentation with an acceptable radiographic working length. Journal of Endodontics 2001;27:49-52.
  11. Radiovisiography for length estimation in root canal treatment: An in vitro comparison with conventional radiography. Int Endod J 1991;24:233-39.
  12. Radiographic practices of dentists undertaking endodontics in New Zealand. Dentomaxillofacial Radiology 2002;31:217-321.
  13. Survey of endodontic treatment in Japan (abstract). Journal of Endodontics 2001;27:236.
  14. An in vivo evaluation of an electronic apex locator that uses the ratio method in vital and necrotic canals. Journal of Endodontics 1998;24: 48-50.
  15. In vitro evaluation of the reliability of the root ZX electronic apex locator. 32 1999:120-23.
  16. Comparison of radiographic and electronic working lengths. Journal of Endodontics 1996;22:173-76.
  17. Radiation dose reduction during endodontic therapy: A new technique in combining apex locator and a digital imaging system. Journal of Endodontics 2000;26:144-47.
  18. Do irrigants affect the precision of apex locators? Journal of Endodontics 1996;22:195.
  19. In vitro comparison of electronic root canal length measuring device and the radiographic determination of working length 2001;111:1165-70.
  20. Endodontic therapy in a 3-rooted mandibular first molar: Importance of a thorough radiographic examination. Journal of the Canadian Dental Association 2002;68:541-44.
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