ABSTRACT
Currently the cleaning and disinfection of the root canal are achieved with the assistance of instruments and irrigating solutions. However, obtaining a root canal completely free of smear layer and debris it is an utopia and is recognized by several authors. To get a successful root canal therapy it is important to regarding the combination of proper instrumentation, irrigation, and obturation of the root canal. During the mechanical preparation, the instruments cut the dentin and produce a mass composed of inorganic and organic material that was called smear layer, having a thickness which ranges from 1 to 5 µm. In case if there are blocking the entrance of dentinal tubules, it is called smear plug, possessing constitution identical to smear layer. Furthermore, studies have shown that removal of this layer promotes the permeability of the dentine by improving the diffusion and action of drugs into the conduct, allowing greater penetration and producing one of sealers in lateral root canals and dentinal tubules.
