Bacteriologic evaluation of ultrasonic root canal instrumentation.

The antibacterial effect of ultrasonic instrumentation in the treatment of infected root canals was clinically evaluated. Sodium hypochlorite solution (0.5%) was used as an irrigant, but no antibacterial intracanal dressing was used between the appointments. The ultrasonic technique eliminated the bacteria from the canals more efficiently than hand instrumentation alone. Even though ultrasonication definitely improves the procedure of root canal disinfection, the use of an antibacterial dressing between appointments is necessary to achieve as complete a reduction in bacterial levels as possible.