The effectiveness of passive ultrasonic irrigation on intraradicular Enterococcus faecalis biofilms in extracted single-rooted human teeth.
OBJECTIVE
To compare the efficacy of passive ultrasonic irrigation with 1% sodium hypochlorite, with that of conventional syringe irrigation with 1% sodium hypochlorite, on intraradicular Enterococcus faecalis biofilms in extracted single-rooted human teeth.


METHODS
Biofilms of E. faecalis (strain OMGS 3202) were grown on the prepared root canal walls of 48 standardized root halves which had been longitudinally sectioned. Following reapproximation, the roots were divided into four groups of twelve. The two experimental groups were treated with conventional syringe irrigation with 1% sodium hypochlorite solution (experimental group A) and passive ultrasonic irrigation with 1% sodium hypochlorite solution (experimental group B). Of the two control groups, the first was treated with conventional syringe irrigation with sterile saline solution (control group C), whilst the second control group (D) received no irrigation. The root halves were processed for scanning electron microscopy. Three images (x 700), coronal, middle and apical, were taken of the twelve root halves in each of the four groups, using a standardized protocol. The images were randomized and biofilm coverage assessed independently by three calibrated examiners, using a four-point scoring system.


RESULTS
There were no significant differences in the scores for remaining biofilm coverage between group A (conventional syringe irrigation with 1% sodium hypochlorite) and group B (passive ultrasonic irrigation with 1% sodium hypochlorite) at the three observed levels. There was a significant difference between both experimental groups (groups A and B) and group C (conventional syringe irrigation with sterile saline solution) (P < 0.001) at all three observed levels.


CONCLUSIONS
Both conventional syringe irrigation and passive ultrasonic irrigation with 1% sodium hypochlorite were effective at completely removing intraradicular E. faecalis biofilms. Conventional syringe irrigation with sterile saline solution was only partially effective at removing the biofilms.
Department of Conservative Dentistry, King's College London Dental Institute, London, UK.
B
B
Bhuva
S
S
Patel
R
R
Wilson
S
S
Niazi
D
D
Beighton
F
F
Mannocci
D018441:Biofilms / Q000187:drug effects*; D016009:Chi-Square Distribution; D003786:Dental Pulp Cavity / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000187:drug effects*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D015588:Observer Variation; D012388:Root Canal Irrigants / Q000008:administration & dosage*; D018915:Root Canal Preparation / Q000295:instrumentation*; D012973:Sodium Hypochlorite / Q000008:administration & dosage*; D007507:Therapeutic Irrigation / Q000295:instrumentation; D014465:Ultrasonics
D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite