الفهرس 
Enterococcus Faecalis in secondaryOnly 14 pages are availabe for public view
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Abstract
The aim of the present study was to evaluate the effect of
QMix irrigating solution on the Enterococcus faecalis
population using different irrigation protocols; passive
irrigation, mechanical agitation, passive ultrasonic
irrigation and apical negative pressure by direct count of
colony forming units (CFUs).
A total of 95 human single‐rooted teeth with straight
single canals and mature apices were selected for this
study. To standardize canal instrumentation, teeth were
decoronated, and the roots were adjusted to a
standardized length of 16mm. Instrumentation was
performed by using the Pro‐Taper rotary nickel‐titanium
system in crown down manner according to the
manufacturer’s recommendations until finishing file #4
(40/0.6). During instrumentation, 1 mL of sterile saline was
used at each change of file.
The roots were filled with a 24‐hour pure culture
suspension of E.faecalis grown in Brain Heart Infusion
(BHI) broth. All teeth were incubated at 37°C in sealed vials
for 7 days, replacing the intracanal fluids with freshly prepared 0.9% physiologic saline solution adjusted to No.
1 MacFarland turbidity standard. The suspension was
replenished every 72 hours.
Five teeth were subjected to scanning electron microscopy
to allow visualization of the pattern of colonization and
eighty teeth continued in the study.
Teeth were then randomly divided into a control group of
10 teeth and 4 experimental groups of 20 teeth each.
Groups were divided according to the technique used
during final rinse as follows: for Group I Passive irrigation:
solutions were delivered by a syringe and a 30‐gauge
NaviTip needle, for Group II Mechanical agitation: an F‐File
was used with an electric low speed hand‐piece for irrigant
agitation, for Group III Passive ultrasonic irrigation: the
irrigant was activated by using #25/0.00 taper SS
noncutting ultrasonic tip operated by a piezoelectric
ultrasonic unit at 1 mm from the WL for 1 minute and for
Group IV: specimens were irrigated by using the EndoVac
system according to the protocol described by Nielsen and
Baumgartner (98).Each group was then subdivided into two sub‐groups
according to the type of irrigant. The first sub‐group was
irrigated using 2.5 mL of 2.5% NaOCl, followed by 2.5 mL
of 17% EDTA. For the second sub‐group, 5 mL of QMix™
2in1 was used for final irrigation.
At the end of the irrigation process, the samples were
filled with sterile Brain Heart Infusion broth as a transport
fluid. Each sample was taken using three paper points. The
sterile paper point absorbed the transport fluid, and was
transferred to a test tube containing 1.0 ml of saline. Each
sample was carefully homogenized by vortexed for 30
seconds. Serial 10‐fold dilution (1:10, 1:100 and 1:1000)
was made in saline. Then 0.1 mL from each dilution was
smeared to be inoculated on surface of the plate media
(BHI agar plates), incubated at 37°C for 48 hours, and
colony‐forming units (CFU) per 1 mL were enumerated.
Visible colonies of E.faecalis were then counted in every
plate and the number of colonies/plate was multiplied by
the corresponding dilution factor and by 10 to determine
the total colony forming units (CFU) per mL of sample.