الفهرس 
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Abstract
Summary and Conclusion
The present in vitro study was aimed to assist the efficacy of three
different intra-canal medicaments (calcium hydroxide powder, metronidazole
powder and chitosan powder) in combination with two types of vehicles (2%
Chlorhexidine solution and sterile water) to inhibit the growth of E. faecalis
biofilm in the root canal by colony forming unit per milliliter (CFU/ml) and
scanned by Scanning Electron Microscope.
In the present study 180 unidentified single rooted human mandibular
premolars extracted for orthodontic and periodontal reasons were collected and
divided into six groups: pilot Study (n= 30), negative control group (n= 15),
positive control group (n= 15), group A (n= 40), group B (n= 40) and group C
(n= 40).
High speed diamond disc under water coolant was used to standardize
root length of all teeth, access cavities were prepared using Endo-Z bur under
water coolant. Patency of canals was approved and ProTaper Gold rotary files
were used for cleaning and shaping of the canals according to manufacture
instructions. Irrigation of each canal was done using 1ml of 2.5% sodium
hypochlorite for 1 minute after each file. 1ml of 17% EDTA for 1 min was used
to eliminate the smear layer, normal saline was introduced into the canals
between the two previous irrigants and also used as the final rinse. Teeth
sterilization was done using gamma radiation.
Roots of negative control group were chosen randomly and kept empty to
check sterility of experiment. One hundred sixty five roots were infected with
the previously prepared E. faecalis suspension and incubated at 37o C and 100%
humidity. Every 24 hours repeated infection with 10 μl of fresh inoculated media
was applied inside all the roots.
Summary and conclusion
63
Pilot study was done to confirm formation and maturation of E.faecalis
biofilm onto dentin of root canals by SEM examination at six time intervals.
Roots of positive control group were selected by the allocator and inoculated to
check the viability of E.faecalis biofilm throughout the experiment.
Groups A, B, and C were further subdivided into 2 subgroups according
to the type of vehicles (chlorhexidine 2% solution and sterile water). The intracanal medicaments paste was introduced into the infected root canals and the
coronal portion was sealed by temporary filling and all samples were incubated
at 37oC and 100% humidity for two weeks.
Each root was irrigated with 20 ml sterile water to remove the contents of
root canals, The root canals were filled with sterile water as a transport fluid,
then #15 K-file was placed into the canal to within 1 mm of working length and
circumferentially filed before sterile absorbent paper points adsorbed the
transport fluid and transferred it to a test tube containing 1 ml of sterile broths
corresponding to each root, 1μl suspension of each tube was cultured on MEnterococcus agar plates and were incubated at 37°C for 24 hours.
After incubation for 24 hours, quantitative evaluation of the intra-canal
medications effect was done using colony forming units per milliliter (CFU/ml)
and SEM.
The results of this study showed that the least (CFU/ml) was recorded by
metronidazole + chlorhexidine solution, and the highest (CFU/ml) was recorded
by chitosan + sterile water.
Summary and conclusion
64
The conclusions of the present study were:
14 days period was found to be sufficient for maturation of intra-canal
E.faecalis biofilm.
Metronidazole and calcium hydroxide were more effective against intracanal E. faecalis biofilm.
Using CHX 2% solution increased the efficacy of used medicaments
against intra-canal E. faecalis biofilm more than sterile water.
None of the intra-canal medicaments used completely removed the intracanal E. faecalis biofilm