Abstract
Several studies have evaluated the influence of torsion and bending loads on the mechanical
resistance of nickel-titanium instruments. The aim of the present study was to analyze
the influence of previous angular deformation on K3 files resistance to flexural fatigue.
New files and files previously submitted to different angular deformation were tested
for flexural fatigue, and the number of cycles to fracture was compared. The results
indicated that as the angular deformation increases, the number of cycles attained
under flexural fatigue condition decreases. A reduction of fatigue resistance was
registered even when a significant plastic deformation was not imposed. From the obtained
results, it may be suggested that the sequential loading, including torsion and flexural
fatigue, can be responsible for instrument separation during clinical practice. Successive
torsion overloads, occurring together with flexural fatigue, reduce the mechanical
resistance of nickel-titanium files.
Key Words
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Article info
Publication history
Published online: October 16, 2007
Footnotes
Supported by FAPERJ and CNPq.
Identification
Copyright
© 2007 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
