Smear layer removal potential of a naturally occurring antioxidant: An in-vitro scanning electron microscopic study

The primary objective of endodontic therapy is to thoroughly disinfect the root canal system. The smear layer formed during instrumentation presents a substantial impediment to optimal root canal disinfection, as it provides a medium for bacterial proliferation, hinders the penetration of disinfecting agents, and creates a physical barrier that undermines the efficacy of root canal sealers by obstructing the interface between the obturating core material and the dentinal tubules. Consequently, the removal of the smear layer is of utmost importance. This in vitro study assessed the efficacy of 20% N-acetyl-cysteine (NAC) and 17% ethylenediaminetetraacetic acid (EDTA) in removing the smear layer from root canal dentine. Ninety-two single-rooted teeth were instrumented and divided into two groups: 20% NAC for 1 minute, and 17% EDTA for 1 minute. Following irrigation, the samples were analyzed using scanning electron microscopy (SEM) to evaluate smear layer removal in the coronal, middle, and apical thirds of the root canals. No statistically significant difference was observed between 20% NAC and 17% EDTA in their ability to remove the smear layer across all sections of the root canal. 20% NAC demonstrates smear layer removal capability comparable to 17% EDTA as a final irrigant.