A comparison of 2.0% chlorhexidine gluconate and 5.25% sodium hypochlorite as antimicrobial endodontic irrigants.

Sodium hypochlorite, as an endodontic irrigant, poses problems including toxicity, odor, and discoloration of operatory items. An equally effective, but safer irrigant is desirable. Therefore, we compared the antimicrobial activity of 2.0% chlorhexidine gluconate with that of 5.25% sodium hypochlorite in an in vitro root canal system. Freshly extracted human teeth with pulpal pathosis were instrumented using chlorhexidine, sodium hypochlorite, or saline as irrigants. Microbiological samples were taken from the teeth immediately after accessing the canal, after instrumentation and irrigation, and after standing in an anaerobic atmosphere for 24 h. Irrigation with chlorhexidine or sodium hypochlorite significantly reduced the numbers of postirrigant positive cultures and colony-forming units compared with saline-irrigated teeth. The number of postirrigant positive cultures and the number of colony-forming units in positive cultures obtained from chlorhexidine-treated teeth were lower than the numbers obtained from sodium hypochlorite-treated teeth, but the differences were not statistically significant.