title: Electronic apex locator.
abstract: Locating the appropriate apical position always has been a challenge in clinical endodontics. The electronic apex locator (EAL) is used for working length determination as an important adjunct to radiography. The EAL helps to reduce the treatment time and the radiation dose, which may be higher with conventional radiographic measurements. According to recent publications, the accuracy of frequency-dependent EALs appears to be much higher compared with traditional-type EALs (simple resistance type or impedance type). This article reviews the history and the working mechanism of the currently available EALs, and suggests the correct usage of the apex locator for a better canal length measurement.
authors.affiliation: Department of Conservative Dentistry, School of Dentistry, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, Korea.
authors.forename: Euiseong
authors.initials: E
authors.lastname: Kim
authors.forename: Seung-Jong
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004582:Electronics, Medical / Q000295:instrumentation*; D006801:Humans; D009811:Odontometry / Q000295:instrumentation*; D018915:Root Canal Preparation / Q000295:instrumentation; D019227:Tooth Apex / Q000033:anatomy & histology*