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Title Use of An Electronic Apex Locator May Lead To Significant Overestimation in Working Length During Endodontic Retreatment
Clinical Question In endodontically treated teeth requiring retreatment, does use of an electronic apex locator (EAL), compared to radiography, improve accuracy in determining working length?
Clinical Bottom Line Use of an EAL during endodontic retreatment leads to greater overestimation of WL than during initial treatment. This is supported by an in vitro study using extracted human teeth.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 25443281Mancini/2014n = 50 extracted human teethLaboratory study
Key results50 single-rooted teeth were extracted and canal length was measured with a #10 K-file using the visual technique (DL). The WL was recorded using an EAL (EL1). The canals were then cleaned and shaped and obturated. One week later an EAL was used to determine WL (EL2) during standard retreatment procedures. Results of this study indicate a statistically significant overestimation of WL with an EAL in endodontic retreatment compared with initial treatment (p<.05).
Evidence Search ("electronics"[MeSH Terms] OR "electronics"[All Fields] OR "electronic"[All Fields]) AND ("Apex"[Journal] OR "apex"[All Fields]) AND locator[All Fields] AND accuracy[All Fields] AND endodontic[All Fields] AND ("retreatment"[MeSH Terms] OR "retreatment"[All Fields])
Comments on
The Evidence
This is an in vitro study and its results may not directly correlate to clinical application. EALs work by measuring the difference in electric resistance between the file and the tissue at the apical foramen, where the dentin acts as the resistive material. Although the article did demonstrate a significant difference between the EAL’s ability to establish WL in untreated vs previously treated canals, the observation was made that it is nearly impossible to remove all of the gutta percha from the canal during retreatment. The inability to completely remove the GP, especially in true clinical conditions, may further distort the EAL’s WL estimation.
Applicability It is important for clinicians to consider the findings that the research demonstrates. Over-instrumentation can lead to failure of the clinician’s ability to obtain a proper seal in the re-treated canal and/or it may lead to overfill of the canal. The use of an EAL has been demonstrated to overestimate the length of the canal especially in previously treated canals where proper length control is essential.
Specialty/Discipline (Endodontics) (General Dentistry) (Restorative Dentistry)
Keywords Electronic apex locator, GuttaCore, ProTaper Obturator, retreatment, working length
ID# 2914
Date of submission: 08/20/2015spacer
E-mail robert.loftus@ucdenver.edu
Author Robert J. Loftus
Co-author(s) e-mail
Faculty mentor/Co-author Ethelyn Thomason, DMD
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