title: Occurrence of no-function of two electronic apex locators: an in vivo study.
abstract: OBJECTIVE
  This in vivo study was aimed at quantifying the electronic no-function rate of 2 electronic apex locators, ApexPointer and Novapex, and evaluating whether their operation is affected by the type of applied treatment, patient's age, and the type of tooth.
  
  
  METHODS
  A total of 209 root canals were included in this study. For each canal, the electronic length was determined and verified by radiography. Whenever the electronic device failed to provide a value, it was recorded as an electronic no-function. Experimental data were statistically tested with chi-squared through Statview.
  
  
  RESULTS
  For both apex locators, the no-function rate remained around 15% and did not seem to be affected by the age of patients. A statistically significant relationship was found between no-function rate and retreatment (P < .05). The type of tooth had no influence on the no-function rate.
  
  
  CONCLUSIONS
  Under the conditions of this assessment in vivo, the 2 apex locators proved to give no value in about 15% of the cases. Further investigations are necessary to clear up the links between no-function and retreatment or age.
authors.affiliation: Service d'Odontologie, Centre Hospitalier Universitaire, Brest, France.
authors.forename: Valerie
authors.initials: V
authors.lastname: Chevalier
authors.forename: Reza
authors.initials: R
authors.lastname: Arbab-Chirani
authors.forename: Marie
authors.initials: M
authors.lastname: Nicolas
authors.forename: Vincent
authors.initials: V
authors.lastname: Morin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D004868:Equipment Failure; D019544:Equipment Failure Analysis / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009811:Odontometry / Q000295:instrumentation; D011859:Radiography; D015203:Reproducibility of Results; D012390:Root Canal Therapy / Q000295:instrumentation*; D019227:Tooth Apex / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D055815:Young Adult