الفهرس 
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Abstract
The present study aimed to compare the efficiency of single file system
(Neoniti) versus multifile system (Protaper Universal) in reducing
Enterococcus Faecalis biofilm in the root canals using different methods of
activation of irrigation (conventional syringe, passive ultrasonic irrigation
and vibringe).
Fifty – four human extracted mandibular permanent first and second
molars were selected. The mesial root of each molar was separated at the
bifurcation. Root canals selected were type III. 48 roots were divided into 2
equal groups (n=24) and they were equally distributed in length. Root canals
were enlarged to ISO # 20. Smear layer was removed. They were packed in
two separate sterilization pouches and steam autoclaved at 121
°
C for 30
minutes. A clinical isolate of E. faecalis from the Microbiology laboratory
was used for biofilm formation. Monitoring of bacterial biofilm development
onto root canal dentin was assessed by SEM examination after three weeks
using the positive control group (n=3).
3 samples were served as the negative control group to check for the
sterility of the procedures and 3 samples were served as the positive control
group to check for bacterial viability throughout the experiment & used as
indicators for biofilm formation.
Pre-instrumentation bacterial sampling (S1) was taken from the two
experimental groups and the negative control group by placing # 15 K-file
into the canal to within 1 mm of working length and circumferentially filed
for 10 seconds then a sterile absorbent paper point size 15 was placed in the
root canals, adsorb the transport fluid (Saline) and transferred into a test tube
containing 1.0 ml of 0.9% sterile saline.
Each sample was diluted 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.
Root canal instrumentation was done according to the manufacturer
instructions for the 2 experimental groups:
group I: (n=24) (Protaper universal) till F2 (25/0.08).
group II: (n=24) (Neoniti) single file (25/0.08).
Patency by K-file # 10 and irrigation by saline (total amount for the 2 root
canals = 10 ml) by 28 gauge needle were made between each file and the
next.
Post instrumentation bacteriologic sampling (S2) was taken by paper point
size 30.
Each group will be further subdivided into 3 subgroups (n = 8 ) according
to the method of activation of irrigation :
a) Subgroup A: By conventional plastic syringe.
b) Subgroup B: By Passive Ultrasonic Irrigation.
c) Subgroup C: By vibringe.
Post activation bacteriologic sampling (S3) was taken by paper point size 30.