freshly extracted human premolar teeth with straight single root canal were preferred
and stored in distal water. standard root length of 12 mm were maintained by decoronating
the teeth and then divided into 5 groups (n = 12) randomly. Working length was measured with #10 K-files and deduction of 1mm
was done from recorded root length.
irrigation protocol was followed for three groups. After using each file and
before proceeding to the next canals were irrigated with 2 ml of 5.25% NaOCl.
After instrumentation, all teeth underwent final irrigation as follows:-
Group A(control, EDTA) –
1ml of 17% EDTA for 1 minute followed by 3 ml of 5.25% NaOCl.
Group B (Smear Clear)–
1 ml of Smear clear (Sybron Endo, Orange, CA) for 1 minute followed by 3 ml of
Group C (Smear OFF) –
1 ml of Smear OFF (Vista dental,) for 1 minute followed by 3 ml of 5.25% NaOCl.
continuous soft chelating irrigation protocol was followed for 2 Groups. Group
D- Chloroquick Low (innovationsendo) and Group E – Chloroquick High (innovationsendo). After use of each file
canal was irrigated with 2 ml of respective Chloroquick solution. After
instrumentation, all teeth underwent final irrigation as follows:-
Group D (Chloroquick Low)
– 1 ml of Chloroquick Low solution (9%HEBP + 3%NaOCl) for 1 minute and final rinse with 3 ml same
Group E (Chloroquck High)
– 1 ml of Chloroquick High solution (18%HEBP + 5.25%NaOCl) for 1 minute and
final rinse with 3 ml of same solution.
In-between solutions, 5 ml of distilled water was used
for rinsing canal walls and solutions were introduced with the help of a 30-G
side vented needle (innovationsendo), which penetrated within 1 to 2 mm from
the working length. In the end 5ml of distilled water were used to rinse root
canal walls which were dried with paper points.
In the end of entire procedure, two longitudinal
groves were prepared with the help of diamond disc without cutting into the
canal. Grooves were prepared on the buccal and lingual surfaces of each root. Chisel
was used for splitting the teeth. Then the specimens were mounted on the
metallic stubs and examined by a scanning electron microscope (FEI Quanta 200
FE-SEM MK2, Netherlands). Images were taken at2000×magnifications coronal (9 mm
to apex), middle (6 mm to apex), and apical (3 mm to apex) third of each
Scoring criteria given by Torabinejad M, Khademi AA
et al. where scores were given as follow score 1 = no smear layer; no smear
layer was observed on the surface of the root canals and all tublues were open
and clean; score 2 = moderate smear layer; no smear layer was observed on the
surface of the canal, but debris were present in tubules; score 3 = heavy smear
layer; the smear layer covered the root canal surfaces and debris were present
An endodntist who was unaware of groups and coding evaluated
and scored all the images to exclude observer bias. Repeated evaluation was
done to ensure intra-examiner consistency. Data were analyzed with the help of
Kruskal-Wallis and Mann- Whitney U tests; p values were computed and compared
with the p = 0.05 level.