Influence of canal morphology on the sealing ability of two obturation techniques

Aim
The aim of this study was to compare the seal obtained by
two obturation techniques: Lateral condensation and Thermafil
(Maillefer, Ballaigues, Switzerland) in different root canal shapes.
Methodology
Fifty extracted permanent human lower premolar
teeth were used in this study. All the teeth were instrumented by a
‘crown-down’ technique and allocated randomly into the two groups:
Thermafil and lateral condensation. A microleakage study by a 2%
aqueous methylene blue dye solution was performed. Six horizontal
sections were produced and digitally recorded by a stereomicroscope
at 25
×
magnification further transferred in NIH-IMAGE software and
analysed. Each section was divided into four quadrants, overlapping
to each image a cross designed in the centre of the root canal. The
degree of infiltration was scored from A (excellent) to E (poor) and the
shape of the root canal assigned into three groups: irregular, oval and
round. Data were statistically analysed by nonparametric Mann–
Whitney
U
-test.
Results
Scores of A and B occurred as follows: irregular – 9.4 T vs.
2.9% LC (
P
< 0.001); oval – 13.1 T vs. 5.1% LC (
P
< 0.001); round –
31.3% T vs. 8.7% LC (
P
< 0.0001)
Conclusions
Under these experimental conditions Thermafil
obturation technique demonstrated better results independent of
canal section morphology. Round canals were sealed better by both
techniques.