Evolution of Electronic Root Canal Length Measurement Device -A Literature Review

Abstract

Summary: An electronic apex locator(EAL) is a device used to measure the working length (WL) of the
root canal space(RCS) and proved to be a great help to the endodontist reducing radiation exposure of
both patients and clinicians and providing accurate reading for the WL. Evolution of different generations
of EAL helped to eradicate the shortcomings of the previous generations providing precise measurement
of the WL. Electronic Apex locators are used to detect any perforations, furcation involvement, also used
to detect horizontal fractures, also to detect internal or external resorption. With so many uses, it is still
contraindicated in patients with pace makers and inaccurate reading in canals with common irrigants like
Ethylenediamine tetraacetic acid and sodium hypochlorite. It requires dry or partially dry canals to give
readings with accuracy. It also gives inaccurate reading in the presence of semi-conductive materials and
hence the canals should be free of them. Though it provides almost precise measurement of the WL it cannot
be replaced with radiographs but can be used as an adjunct with it. Pre- and post-operative radiographs are
still necessary for the success of the endodontic treatment as it provides an idea for any periapical lesion
and degree of curvature of roots. Acceptance of an electronic apex locator to determine the correct WL
has still not gained approval worldwide. Lack of exposure to the technology by the operator, inadequate
knowledge of the root canal anatomy and cost of the instrument are also the factors for it not gaining
worldwide acceptance.