Assessment of the accuracy of a fifth generation apexlocator (in vitro study)

Gh. Subhi, Ahmed; A.R. Majeed, Manhal

	Assessment of the accuracy of a fifth generation apexlocator (in vitro study)
Journal of baghdad college of dentistry
Article 1, Volume 23, Issue 1, 2011, Pages 12-17
Authors
Ahmed Gh. Subhi; Manhal A.R. Majeed
Abstract
ABSTRACTBackground: The use of electronic apex locators for working length determination eliminates many of the problemsassociated with the radiographic measurements (interference of anatomical structures, errors in projection such aselongation or shortening, and lack of three-dimensional representation). Its most important advantage overradiography is that it measures the length of the root canal to the apical constriction, not to the radiographic apex.The aim of this study was to assess the accuracy of a new fifth generation apex locator (Joypex 5) in recording theapical constriction and comparing it with a third generation apex locator (Root ZX) in vitro.Materials and method: Twenty four single-rooted sound human premolars, extracted for the purpose of orthodontictreatment and with fully-formed roots, were used in this study. Endodontic access cavity was prepared in each toothand canal patency up to the apical foramen was checked with a #15 stainless steel K-file. No root canalpreparation was performed. Root canal length measurement was done directly and electronically using two apexlocators (Joypex 5 and Root ZX). Direct measurement of the root canal length was done by introducing a #15 K-fileinside the root canal until its tip was just visible at the apical foramen, then removed from the root canal and itslength was measured (in mm) and subtracted by 0.5 mm. For electronic measurement, the teeth were fixed in asponge soaked in saline and the root canals were also filled with saline. The lip electrode was attached to thesponge and the apex locators were used according to the manufacturers' instructions. The file holder was clipped tothe metal shaft of a #15 K-file and the file was then inserted inside the root canal and advanced until the displayreading on the LCD of the apex locator was "0.5". The file was then removed from the root canal and its length wasmeasured (in mm). The differences between the readings of each apex locator and the actual length of each canalwere computed, and the results were analyzed statistically by paired t-test using SPSS Version 13.Results: The results of this study showed that the Joypex 5 apex locator showed a lower mean difference than theRoot ZX apex locator as compared with the actual length, which was statistically significant (p<0.05). Concerning theaccuracy of the two apex locators, Joypex 5 apex locator recorded the apical constriction exactly in 67%, while theRoot ZX apex locator in only 25%. Within ±0.5 mm from the actual length, the accuracy of the Joypex 5 and the RootZX were 83% and 67%, respectively. Within ±1 mm from the actual length, the accuracy of the Joypex 5 and the RootZX were 100% and 96%, respectively.Conclusion: The Joypex 5 apex locator which is a fifth generation apex locator was more accurate in recording theapical constriction as compared with the Root ZX apex locator which is a third generation apex locator.Key words: Apex locator, fifth generation, accuracy. (J Bagh Coll Dentistry 2011;23(1):12-17)

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