A preliminary scanning electron microscopic study of root canals after endodontic procedures

By McComb D and Smith DC

Date: 11/1976
Journal: JOE


•Purpose: demonstrate the effects of different irrigating solutions used after instrumentation.

•N=  (Not mentioned) Recently extracted, single-rooted, human teeth


oThe canal then was instrumented with progressively larger reamers or files, or both.

o 3 groups:

1.Water irrigation.

2.Chemical irrigation 1% , 6% NaOCl, 6% NaOCl+ 3% H2O2, EDTA, RCPrept, Polyacrylic acid.

3.Sealed chemical irrigations for 24 hours.

oEach group had 2 teeth examined under Cambridge SEM.

Most highlighted Results: 

•None of the irrigating used were able to remove both smeared layer and superficial debris completely.

•Instrumentation with water irrigation resulted in dentinal tubules completely obscured by smeared layer.

•When using NaOCl, no debris could be seen but smeared layer was still present.

•Alternate irrigation with H2O2 and NaOCl is not efficient and similar to water irrigation.

•REDTA, when used as an irrigant and particularly when used as a treatment for 24 hours, produced most consistently the cleanest dentin walls. The smeared layer was removed and no debris remained.

•Polyacrylic acid was not as consistently good as the results with REDTA.

Clinical significance

EDTA is most effective in terms of removing the smear layer.