freshly extracted human premolar teeth with straight single root canal were preferred
and stored in distal water. Standard root length of 12 mm were preserved 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.
statistics were expressed as numbers for each group. The efficacy of various
agents for smear layer removal was assessed by comparison of groups using
Kruskal Wallis ANOVA and Mann- Whitney U test. In the above tests, p value less
than or equal to 0.05 (p?0.05) was taken to be statistically significant. All
analyses were performed using SPSS software version 17.
The results for smear
layer scores in each group at coronal, middle and apical are presented in Table
no 1, 2 and 3. The examination of the surface of root canal walls at coronal
third groups showed less or no smear layer (Fig. 1) and there was no statistically significant
samples at middle thirds shows no smear layer or minimal smear layer present
(Fig. 2) and there was no
statistically significant difference at middle layer of root canals (p_0.615). Chloroquick High group showed better smear layer removal at the apical thirds(Fig.
3). Chloroquick High shows statistically significantly better
(p_0.029) as compared to the other groups. Mann-Whitney U test shows that
Chloroquick High is able to remove better smear layer compared to Chloroquick Low
(p_0.028). Choloroquick Low has similar chelating
ability as compared to other solution there is no statically significant
difference at apical third.