title: Electrometric determination of the working length of root canals by means of Apex locator.
abstract: OBJECTIVE
  To evaluate an apex locator in determining the working length of root canals and detecting micro-communications with the pulp chamber.
  
  
  METHODS
  The apparatus was tested on 21 patients, aged 18 - 70, who received endodontic treatment of 34 teeth with 45 root canals. The apparatus was used in compliance with the instructions of the manufacturer. The precision of the instrument was determined by a radiograph of the tooth with a file inserted in it at a depth equal to the length determined with the Apex locator. The obtained results were divided into three groups: canals determined as longer; canals in which the outline of the instrument was close to the roentgenologic apex; and canals determined as shorter.
  
  
  CONCLUSIONS
  The average deviation from the roentgenologic apex was 1.17 mm, which is, in fact, the area of the physiological apex opening - the ideal limits for treatment and obturation. The apparatus can be successfully used to make differential diagnosis is useful of deep caries with pulpitis chronica ulcerosa. It is ergonomic and easy to use.
authors.affiliation: Department of Therapeutic Dentistry, Faculty of Dentistry, Higher Medical Institute, Plovdiv, Bulgaria.
authors.forename: S B
authors.initials: SB
authors.lastname: Vladimirov
authors.forename: I A
authors.initials: IA
authors.lastname: Filipov
authors.forename: L S
authors.initials: LS
authors.lastname: Vangelov
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D011859:Radiography; D012390:Root Canal Therapy