Smear layer in endodontics, preserve or remove?

Introduction: the root canal instrumentation, either by manual or mechanicals methods, will result in a formation of debris layer on dentin surface composted by organic and inorganic tissues, denominated smear layer. Due to the several divergent opinion about its removal or maintenance into the root canal, the clinicians may have a doubt for the most appropriate conduct to be performed in endodontics treatments. Objective: this article aimed collect the mains results obtained by different authors to provide a clear answer capable of improving the treatment prognosis. Methods: for this, were used 25 articles since 1975 to 2014 collected by date base PubMed and Web of Science with the keywords "smear layer", "smear layer removal", "smear layer permeability", "smear layer bacteria" and "smear layer sealing". Conclusion: based in the informations obtained in this review, its was concluded that the smear layer removal can, not only, improve the antimicrobial action of the irrigants agents and intracanal medicaments, but also provide a most efficient sealing of the fillingmaterial to dentine wall, reducing the chances to occur a leak in its interface.