Comparative Evaluation of Smear Layer Removal by Various Endodontic Irrigating Solutions-An In vitro Study

Present study aimed to investigate the smear layer removal of three different endodontic irrigating solutions: Group I-17% EDTA followed by 3% NaOCl, Group II-combination of hydrogen peroxide (12.8 mL/100 mL), sodium benzoate (0.021 mL/100 mL), acetic acid (2.664 mL/100 mL), and water; Group III-combination of 4.25% citric acid, 3% doxycycline, 9% propylene glycol, and water.

One hundred twenty-three extracted premolars were stored and decoronated. The root canals were biomechanically prepared with ProTaper rotary instruments (Dentsply) up to size F5. During instrumentation, 1 mL of 2.5% NaOCl was used as an intracanal irrigant. After instrumentation, one hundred and twenty samples were randomly divided into three experimental groups according to different irrigating solutions used. As control, three specimens were prepared in same manner as experimental groups but only irrigated with 2.5% NaOCl and distilled water not with acids or chelators. Finally, each root canal of all the experimental samples were irrigated with 2.5% NaOCl and distilled water, dried, temporarily sealed and stored and subjected to scan under SEM.

Smear layer removal efficacy of all the experimental groups were compared at all sites (coronal, middle, apical) with one another and P value was found to be <0.001, that is, highly significant.

Combination of 4.25% citric acid, 3% doxycycline, 9% propylene glycol, and water showed effective smear layer removal from the coronal, middle, and apical thirds as compared to other irrigating solutions than other irrigating solutions.