The Accuracy of Three Apex Locators in Determining the Location of Strip Root Perforation in Different Environments

The purpose of this study was to assess the accuracy of Root ZX (J. Morita USA, Inc., Irvine, CA, USA), Raypex 6 (VDW, Munich, Germany) and i-Root (S-Denti Co. Ltd Seoul, Korea) electronic apex locators (EALs) in detecting strip root perforations in dry condition, and in presence of 0.9% saline (NaCl), 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 17% ethylenediaminetetraacetic acid (EDTA) and blood.

This ex vivo study evaluated 30 extracted human mandibular first molars. After mesiobuccal canal preparation, strip perforation was artificially created in the coronal third of the canal. The actual length (AL) of the canal to the perforation site was measured using a # 70 K-file under a stereomicroscope under 20× magnification. The teeth were then mounted in an alginate mold. The electronic length (EL) of the canal to the perforation site was measured by each apex locator in different environments. The difference between the EL and AL was calculated for each tooth. Statistical analyses were performed using the Friedman and post hoc Dunn tests at P<0.05 level of significance.

Most accurate measurements were seen in CHX environment for all three EALs. Root ZX mini in CHX environment showed most accurate reading but no significant difference was observed in three EALs in CHX environment. There was no significant difference between different environment in Root ZX mini (P>0.05). The most difference between the EL and AL were observed in NaOCl environment in Raypex and iRoot (P>0.05).

Based on this ex-vivo study, the most accurate measurements were seen for all three EALs in CHX medium. The presence of irrigation solution affected the accuracy of all EALs. Root ZX showed better results compared to other EALs in determining the location of perforation in different environments, but this difference was not significant.