The effect of chlorhexidine gluconate irrigation on the root canal flora of freshly extracted necrotic teeth.

Forty freshly extracted teeth with necrotic pulps were endodontically treated under simulated clinical conditions. Bacteriologic samples were obtained before during, immediately after, and 24 hours after instrumentation, irrigation, and medication either with 0.2 percent chlorhexidine gluconate or with sterile saline. There was a highly significant (p less than 0.0049) reduction in microorganisms in the chlorhexidine-treated specimens after the instrumentation and irrigation procedures. Further significant reductions were noted after intracanal dressing of the teeth for 24 hours with the chlorhexidine gluconate solution. The teeth treated with saline also demonstrated a generalized decrease in flora after the biomechanical procedures. However, there was an absolute increase in numbers of microorganisms for 80 percent of the uniradicular and 50 percent of the multiradicular specimens when no intracanal, antimicrobial dressing was applied. It was concluded that chlorhexidine gluconate in a 0.2 percent solution can be an effective antimicrobial agent when used as an endodontic irrigating solution and that as an intracanal, interappointment dressing, chlorhexidine helps to further reduce bacteria remaining within the root canal system.