Sodium hypochlorite (0.5%–6%) remains today the most frequently used irrigating solution. Its primary advantage is its unique tissue-dissolving effect, which is increased at higher concentrations; at 5.25% it requires only about 30 minutes to completely dissolve pulpal tissues (Türkün and Cengiz, 1997). The antibacterial effect appears to be only partially based on concentration (Byström and Sundqvist, 1983; Siqueira et al., 2000), whereas the fungicidal effect is better at higher concentrations (Sen et al., 1999). Sodium hypochlorite is, however, not effective against Enterococcus faecalis, and chlorhexidine (CHX) is the best alternative.
Chlorhexidine can be used as an irrigating solution or a root canal dressing (in gel form) and has fungicidal as well as antibacterial effects. Its low toxicity and depot effect (substantivity: Komorowski et al., 2000) make it virtually indispensable today in ca/>