n Vivo Antibacterial Efficacy of Ultrasound after Hand nd Rotary Instrumentation in Human Mandibular Molars

c h bstract he purpose of this prospective, randomized, singlelind study was to compare the in vivo antibacterial fficacy of a hand/rotary technique versus a hand/ otary/ultrasound technique in mesial root canals of ecrotic mandibular molars. The hand/rotary group onsisted of 16 mesial roots prepared with a hand/ otary technique. The hand/rotary/ultrasound group onsisted of 15 mesial roots prepared similarly, folowed by 1 minute of ultrasonic irrigation per canal ith an ultrasonic needle in a MiniEndo unit and 15 L/canal of 6.0% sodium hypochlorite. Canals were ampled before and after instrumentation and after minute of ultrasonic irrigation. Samples were incuated anaerobically on reduced blood agar for 7 days t 37°C, and colony-forming units (CFUs) were ounted. The addition of 1 minute of ultrasonic rrigation resulted in significant (p .0006) reducion in CFU count and positive cultures (p .0047). ogistic regression analysis indicated the addition of ltrasonic irrigation was 7 times more likely to yield a egative culture. (J Endod 2007;33:1038–1043)