Bacteria and their products play an essential role in the initiation and persistence of endodontic diseases. Therefore, eliminating them and preventing the return of their effectiveness is the desired goal in any successful endodontic treatment in the short and long term.~Due to the fact that mechanical preparation of the root canal alone is not capable of removing the entire bacterial content, chemical irrigants were considered necessary to reduce the number of bacteria and toxins resulting from them. Until now, there is no irrigant capable of removing the entire bacterial content from the root canal.~Despite the many advantages of sodium hypochlorite, several studies have revealed the toxicity of the solution in high concentrations of it, and it tends to cause tissue irritation when it comes into contact with the apical tissues.~Chlorhexidine has been used for a long time in dentistry due to its antibacterial properties, long period of effect, and relatively low toxicity. This has prompted its use as an irrigant and an intra-canal dressing in endodontic treatment.
The process of removing bacteria and their products from the root canals is an essential step that is achieved through the combination of mechanical preparation and irrigation with chemicals. However, mechanical preparation alone can not reduce the microbial formations inside root canals, so at least about 35% of the root canal walls remain without the preparation tools reaching them.~Many irrigants were used to irrigate the root canals, as sodium hypochlorite and chlorhexidine are the most famous. Although most studies have proven the effectiveness of sodium hypochlorite with its different concentrations in accomplishing this task, some of them showed the inability of the irrigant fluid to eliminate Enterococcus faecalis inside the canals. These bacteria are highly resistant, and therefore endodontic treatment fails in the long term.