Qualitative analysis of the removal of the smear layer in the apical third of curved roots: conventional irrigation versus activation systems

Abstract

Introduction: The aim of this study was to evaluate the effectiveness of different irrigant agitation techniques on smear layer removal in curved root canals.

Methods: Mesiobuccal canals of 62 extracted lower molars with a curvature of 33 degrees were used and instrumented up to ProTaper F2. The samples were divided into 3 experimental groups according to the final irrigation: conventional irrigation, ultrasonic irrigation, and sonic irrigation by using the EndoActivator system. The control group was composed of 2 specimens without any final irrigation. In all of the experimental groups, 5 mL of 17% ethylenediaminetetraacetic acid was used for 1 minute, and 5 mL of 2.5% NaOCl was used for 30 seconds. The analysis of the apical region was performed via scanning electron microscopy by 3 examiners. The data were submitted to the Kruskal-Wallis and Dunn tests (P < .05).

Results: The activation systems removed significantly more smear layer than did conventional irrigation.

Conclusions: Sonic and ultrasonic irrigation resulted in better removal of the smear layer in the apical third of curved root canals than did conventional irrigation.