title: Effectiveness of ultrasonic files in the disruption of root canal bacteria.
abstract: The physical mechanisms of ultrasound, namely cavitation and acoustic streaming, generated by the Enac-Osada ultrasonic unit were investigated for effectiveness in disrupting Streptococcus mitis. In addition, the bactericidal effect of ultrasound in the presence of 2.5% sodium hypochlorite was examined. Bacterial suspensions were irradiated directly with ultrasound in simulated root canals, and the viability of bacteria was examined after growth on a blood agar medium under anaerobic conditions at 37 degrees C for 5 days. The results indicated that ultrasound per se failed to disrupt bacteria but resulted in increases in the viable counts; the former was considered to be because of the lack of cavitation and the latter because of the dispersal effects of acoustic streaming. The 2.5% sodium hypochlorite solution demonstrated powerful bactericidal activity.
authors.affiliation: Department of Conservative Dentistry, University of Malaya, Kuala Lumpur.
authors.forename: M
authors.initials: M
authors.lastname: Ahmad
authors.forename: T R
authors.initials: TR
authors.lastname: Pitt Ford
authors.forename: L A
authors.initials: LA
authors.lastname: Crum
authors.forename: R F
authors.initials: RF
authors.lastname: Wilson
mesh_terms: D015169:Colony Count, Microbial; D003786:Dental Pulp Cavity / Q000382:microbiology*; D005069:Evaluation Studies as Topic; D012390:Root Canal Therapy / Q000295:instrumentation*; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013291:Streptococcus / Q000187:drug effects / Q000528:radiation effects*; D014464:Ultrasonic Therapy / Q000295:instrumentation*
chemical_list: D012973:Sodium Hypochlorite