title: Accuracy of three electronic apex locators compared with digital radiography: an ex vivo study.
abstract: BACKGROUND
  This study compared (1) the accuracy of three different electronic apex locators (EALs) in detecting the apical foramen ex vivo under clinical conditions; (2) the accuracy of digital radiography and EALs in determining the working length (WL) with visible control under a microscope; and (3) the precision of #10, #15, and #20 K-files in electronic measurements.
  
  
  METHODS
  The length of 101 extracted human teeth was measured with three different EALs (Endex [Osada Electric Co, Tokyo, Japan], ProPex II [Dentsply-Maillefer, Ballaigues, Switzerland], and Root ZX [J. Morita Co, Tustin, CA]), with radio videography (RVG) and compared with the actual length. An endodontic training kit (Pro-Train; Simit Dental, Mantova, Italy) was used during the experimental procedures.
  
  
  RESULTS
  Statistical analysis showed that Endex and ProPex II were more accurate than Root ZX in determining the WL. The paired sample t test showed no statistically significant difference between the accuracy of the two radiographic planes examined. The t test showed no significant difference between the three different K-file sizes measurements.
  
  
  CONCLUSIONS
  Endex and ProPex II were more accurate than Root ZX in determining the actual WL. Instrument sizes of hand files did not affect the accuracy of EALs. EALs showed to be more accurate in determining the WL than RVG.
authors.affiliation: Department of Restorative Dentistry and Endodontics, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Cianconi
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Angotti
authors.forename: Roberto
authors.initials: R
authors.lastname: Felici
authors.forename: Gabriele
authors.initials: G
authors.lastname: Conte
authors.forename: Manuele
authors.initials: M
authors.lastname: Mancini
mesh_terms: D000328:Adult; D003748:Dental Equipment; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D009811:Odontometry / Q000295:instrumentation* / Q000379:methods; D019252:Radiography, Dental, Digital; D015203:Reproducibility of Results; D018915:Root Canal Preparation / Q000295:instrumentation; D019227:Tooth Apex / Q000033:anatomy & histology* / Q000000981:diagnostic imaging