Effect of working length measurement by electronic apex locator or radiography on the adequacy of final working length: a randomized clinical trial

By Ravanshad S, Adl A, Anvar J.

Date: 01/2010
Journal: JOE


Purpose: to evaluate the effect of working length determination by radiograph (Rgs) or electronic apex locator  (EAL)on the adequacy of the final working length.


n: 84 patients with 188 canals were tx by one endodontist and divided to two GPs;

GP.1: WL determination using radiographs only (bisecting angle tech)

GP.2 WL determination using EAL (Raypex5) only. Length adequacy was assessed for master cone and final obturation and categorized in short (>2mm) , acceptable (0-2mm), and over cases (beyond the apex).

– The master cone and final radiographs were evaluated by 2 blinded endodontist.


  • The results of length adequacy in each group for master cone and final obturation are illustrated in Table.1 and 2.
  • EAL GP had higher acceptable cases in master cone and final obturation length than Rgs.
  • EAL had significantly lower over cases than Rgs group for the master cone as well as the final obturation length although it was not significant.
  • Cases with short length were not significant between the two GPs.
  • Clinical consideration:

  • EALs can reduce the rate of overestimation of root canal length.