Accuracy of three electronic apex locators in the presence of different irrigating solutions

Abstract

The present study compared the accuracy of three electronic apex locators (EALs) - Elements Diagnostic®, Root ZX® and Apex DSP® - in the presence of different irrigating solutions (0.9% saline solution and 1% sodium hypochlorite). The electronic measurements were carried out by three examiners, using twenty extracted human permanent maxillary central incisors. A size 10 K file was introduced into the root canals until reaching the 0.0 mark, and was subsequently retracted to the 1.0 mark. The gold standard (GS) measurement was obtained by combining visual and radiographic methods, and was set 1 mm short of the apical foramen. Electronic length values closer to the GS (± 0.5 mm) were considered as accurate measures. Intraclass correlation coefficients (ICCs) were used to verify inter-examiner agreement. The comparison among the EALs was performed using the McNemar and Kruskal-Wallis tests (p < 0.05). The ICCs were generally high, ranging from 0.8859 to 0.9657. Similar results were observed for the percentage of electronic measurements closer to the GS obtained with the Elements Diagnostic® and the Root ZX® EALs (p > 0.05), independent of the irrigating solutions used. The measurements taken with these two EALs were more accurate than those taken with Apex DSP®, regardless of the irrigating solution used (p < 0.05). It was concluded that Elements Diagnostic® and Root ZX® apex locators are able to locate the cementum-dentine junction more precisely than Apex DSP®. The presence of irrigating solutions does not interfere with the performance of the EALs.

Effect of pre-flaring and file size on the accuracy of two electronic apex locators

“…In this study, the length obtained via endodontic measurements was established as the gold standard. This working length has been determined under direct or microscopic visualization and subtracting 1 mm as soon as the measuring file was visible at the apical foramen 5,6 . Thus, the "0.0" mark in the Novapex and the "APEX" of the Root-ZX displays with subsequent retracting to the 1.0 mark were used as an apical endpoint.…”

“…Different accuracy ranges have been considered to evaluate the EALs within 0.5 mm and 1 mm 5,6,8,17,18,26,30 . The Root ZX was able to measure the working length (±0.5 mm) in more than 97% of the cases by taking the apical foramen as a landmark for the actual length 5,26 .…”

Influence of pulp condition on the accuracy of an electronic foramen locator in posterior teeth: an in vivo study

“…16 Recently, many authors, using different research designs, have attested to the accuracy of several EFL models. 12,13,[17][18][19][20] One of the EFLs currently available is the NovApex  (Forum Engineering Technologies Ltd., Rishon Lezion, Israel) that operates based on the impedance principle, i.e., it uses alternating current of two or more frequencies while maintaining a fixed difference or ratio between the frequencies. 21 In other words, based on electrical properties (e.g.…”

“…Similarly, other authors have demonstrated that the presence of irrigating solutions did not interfere with EFL performance in extracted teeth. 17,25 In addition to the influence of fluids and solutions, the influence of pulp condition on the accuracy of EFLs has been increasingly investigated. In vivo studies using teeth scheduled for extraction showed no differences in EFL measurements between vital and necrotic teeth.…”

Performance in vitro of apex locators in determining root length in primary molars

“…Beltrame et al 19 observed accuracy of ±0.5 mm 69% and 65% of the canals in roots without and with resorption, respectively using Root ZX. The studies showing that Root ZX and Root ZX II are the most common EALs used in primary teeth 3,14,[19][20] . This is an electronic canal length measuring device based on the ratio method, which simultaneously measures impedance values at two frequencies (8 KHz and 0.4 KHz) and calculates a quotient of impedances 2 .…”