freshly extracted human premolar teeth with straight single root canal were preferred
and stored in distal water. To maintain standard root length of 12 mm the teeth
were decoronated and then divided into 5 groups (n = 12) randomly. Measurements of the working length
were done by deducting 1mm from recorded root length with #10 K-files
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 D (Chloroquick
Low) 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 two solution, 5 ml of distilled water was
used for rinsing canal walls and solutions were introduced into the canals 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, on the buccal and
lingual both the surfaces of each root two longitudinal groves were prepared with
the help of diamond disc without cutting into the canal. The roots were then
split into two halves with a chisel. Then the specimens were mounted on the
metallic stubs, gold sputtered, and examined by a scanning electron microscope
(FEI Quanta 200 FE-SEM MK2, Netherlands). Images were taken at2000×magnificationscoronal
(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
All the images were scored by an endodontist who was
unaware of the groups and coding system 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.