Abstract
Introduction
This study aimed to compare the torque generated by 4 different files in root canals
with 4 different curvature angles.
Methods
Four brands of nickel-titanium (NiTi) endodontic files were selected: WaveOne Primary
(Dentsply Sirona, Ballaigues, Switzerland), WaveOne Gold Primary (Dentsply Sirona),
ProTaper Universal F2 (Dentsply Sirona), and ProTaper Next X2 (Dentsply Sirona). A
tempered steel block containing artificial canals with 4 different canal curvatures
(15°, 25°, 35°, and 45°) was constructed. Each file was used according to the manufacturer’s
instructions in the dynamic model, with an added 15 axial up-and-down movements of
4 mm at the end of the canal. The generated torque was recorded, and the total and
maximum torque values were measured. Two-way analysis of variance and the Duncan post
hoc comparison test were performed at a significance level of 95%.
Results
A significant correlation between the curvature angle and the type of file system
was observed (P < .05). As the degree of canal curvature increased, the generated total and maximum
torque increased. At 15° and 25°, the NiTi files with reciprocating motion generated
a higher total and maximum torque than files with continuous rotation. ProTaper Universal
of conventional NiTi alloy showed the steepest increase in the generated total and
maximum torque with the increasing curvature angle. The ProTaper Next file had the
lowest torque values at the higher canal angles of 35° and 45° (P < .05).
Conclusions
Despite the study limitations, it can be concluded that root canal curvature, design,
and heat treatment of NiTi files and file kinematics affect the generated torque during
instrumentation.
Key Words
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Article info
Publication history
Published online: July 04, 2021
Identification
Copyright
© 2021 American Association of Endodontists.
