There are many defects in the alternating use of 3% hydrogen peroxide and saline during and after root canal instrumentation in most of hospitals in China. Sodium hypochlorite is widely used abroad in endodontics because of its strong antimicrobial action and tissue solvent activity. And now, sodium hypochlorite is used in China step by step, but chelating agent is seldom used as root canal irrigation in endodontics. Chelating agent′s advantage has been focused recently which is capable of removing the smear layer formed during root canal instrumentation, but is inefficient in dissolving pulpal remnants while sodium hypochlorite can. It is widely accepted that the most effective method to remove smear layer is to irrigate the root canal with chelating agent followed by sodium hypochlorite. This paper reviewed the research process in aspects of chelating agent used as root canal irrigation, contributing to popularize its internal clinical application.
