Smartphone use may not interfere with working of Electronic Apex Locator: Study

The electronic apex locator (EAL) acts as an aid in determining the working length accurately and precisely when doing a root canal treatment. Electronic apex locators help reduce the treatment time and the radiation dose, while the radiographic method aids in diagnosing the root canal anatomy.

On the other hand, the amount of electromagnetic radiation emitted from a digital smartphone is estimated to be low, which is around 42 V/m at 0.1 m dropping to below 7 V/m at 1 m in the standby mode. So, when medical equipment is used in the vicinity of a smartphone, two things must be taken into consideration; one is the amount of electromagnetic radiation they produce and the other is the safe distance at which the equipment should be placed. The EAL is contraindicated in patients with pacemakers due to electromagnetic interference.

Likewise, one of the major concerns regarding an EAL is the inaccuracy caused by the electromagnetic interference due to the usage of smartphones in the ambiance.24 To prevent electromagnetic interference from a smartphone, various measures like using it in nonpatient area, restriction in the clinical area, and using it at a distance of more than 1 m from the medical equipment is preferred.

Hence, Cruz Nishanthine and associates at the Department of Conservative Dentistry and Endodontics, Sri Venkateswara Dental College and Hospital, Chennai, Tamil Nadu, India, considered it essential to determine the reliability of the electronic apex locator (EAL), in the presence and absence of a smartphone during working length determination.

The authors included thirty patients requiring root canal treatment in this study. The working length was measured. 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 criterion.

The authors observed that there was no significant difference for electronic working length measurement in the presence or absence of smartphones used.

Hence, they concluded that "smartphones can be used in the vicinity without the fear of electromagnetic radiation interference with the EAL during the working length determination."