Aim: The aim of this clinical study was to determine the reliability of the electronic apex locator (EAL), in the presence and absence of a smartphone during working length determination. Materials and methods: Thirty patients requiring root canal treatment were included in this study. The working length was measured using DentaPortZX, a third-generation apex locator. Two smartphones were used in this study, an Apple iPhone 6s and a Samsung S7. For each canal, electronic working length was determined using a no 15 K-file under three different criteria: no smartphone was placed next to the EAL; an iPhone 6s with activated Wi-Fi, Bluetooth, and calling mode was placed next to the EAL; and Samsung S7 with activated Wi-Fi, Bluetooth, and calling mode was placed next to the EAL during the working length determination. Working length was determined thrice for each canal following all the three criteria and an average of the three values was considered as the final value for each criteria. Results: It was possible to determine the working length using an EAL under all three experimental conditions. The results of the nonparametric test, Kruskal-Wallis ANOVA, was found to be nonsignificant. No significant difference (p = 0.991) was found for electronic working length measurement in the presence or absence of smartphones used in this clinical study. Conclusion: The results of this clinical study conclude that smartphones can be used without the fear of electromagnetic radiation interference to the EAL during working length determination.
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