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Título
Influencia de los factores relacionados con la fatiga cíclica de las limas endodónticas de NiTi
Autor(es)
Director(es)
Materia
Tesis y disertaciones académicas
Universidad de Salamanca (España)
Tesis Doctoral
Academic dissertations
Fatiga
Clasificación UNESCO
3213 Cirugía
Fecha de publicación
2022
Resumen
[EN] The endodontic rotary and reciprocating files of NiTi has reported to exhibit
unexpected fractures inside the root canal system during the root canal
treatment; which can affect the prognosis of the endodontic therapy. Therefore,
it is important to assess the variables related to this intraoperative complication.
Aim: To analyze the influence of the variables related to cyclic fatigue on the
fracture resistance of NiTi endodontic instruments.
To analyze the influence of the apical diameter and taper of NiTi rotary
endodontic instruments on their resistance to cyclic fatigue.
To analyze the influence of cross-sectional design and pitch on the mechanical
behavior of NiTi endodontic instruments under bending and torsional conditions.
To analyze the influence of the cross-sectional design of NiTi rotary endodontic
instruments on the resistance to cyclic fatigue.
To analyze the influence of the NiTi alloy of endodontic rotary instruments on
the resistance to cyclic fatigue.
To analyze the influence of the pecking motion frequency of NiTi rotary
endodontic instruments on their resistance to cyclic fatigue.
To analyze the influence of the movement of NiTi rotary and reciprocating
endodontic instruments on their resistance to cyclic fatigue.
To analyze the influence of reciprocating movements of NiTi alloy endodontic
reciprocating instruments on their resistance to cyclic fatigue.
To analyze the influence of the number of uses and sterilization cycles of NiTi
alloy endodontic reciprocating instruments on their resistance to cyclic fatigue.
To analyze the resistance to cyclic fatigue of new NiTi endodontic systems.
To analyze the influence of the radius and angle of curvature of the root canal
system on the mechanical behavior of NiTi endodontic instruments.
To analyze the volumetric wear of NiTi endodontic reciprocating instruments
subjected to cyclic fatigue.
To analyze the removal capacity of separated NiTi alloy endodontic rotary
instruments within the root canal system and the wear of root dentin Materials and Methods: In vitro and finite element methods were performed for
analyzing the variables related to the cyclic fatigue.
Results: Statistical analisys were performed in order to assess the statistical
significant differences among the parameters of each variable.
Conclusions: The variables analized influences on the resistance of the NiTi
alloy endodontic instruments to cyclic fatigue.
The increased apical diameter and taper of NiTi endodontic rotary files
decreased their resistance to cyclic fatigue.
The use of files with a triangular-shaped cross-section and a small pitch are
recommended in order to minimize ledging and maximize fatigue life.
The double S-shaped cross-section of NiTi alloy endodontic files shows higher
cyclic fatigue resistance than the rectangular cross-section, the convex
triangular cross-section, and the triangular cross-section of NiTi alloy
endodontic files.
The NiTi CM-Gold wire alloy of the ProTaper Gold endodontic rotary files
resulted in greater resistance to cyclic fatigue than ProFile Vortex Blue,
ProTaper Next, and ProTaper Universal endodontic rotary files
A low frequency of pecking motion is recommended to reduce the risk of failure
of endodontic rotary files associated with cyclic fatigue.
NiTi alloy endodontic rotary files using reciprocating movement at 350 rpm with
120° counterclockwise and 30° clockwise motion exhibit greater resistance to
dynamic cyclic fatigue than files used with a reciprocating movement at 400 rpm
with 120° counterclockwise and 30° clockwise motion, continuous rotational
speed at 200 rpm, continuous rotational speed at 350 rpm, or continuous
rotational speed at 500 rpm; it is therefore advisable to use reciprocating
movements at a low speed.
The ReFlex Smart reciprocating movement increased the cyclic fatigue
resistance of endodontic reciprocating files compared with traditional
reciprocating movement.
The time of use of NiTi endodontic reciprocating files negatively afects dynamic
cyclic fatigue resistance; however, dynamic cyclic resistance is not afected by
the number of sterilization cycles.
Smarttrack NiTi alloy endodontic reciprocating files display greater resistance to
cyclic fatigue than Endogal and Path Max Pro NiTi alloy endodontic rotary files,
due to the reciprocating movement and metallurgical composition.
Significant influence of the root canal geometry on the fatigue life of the NiTi
rotary files and reveal the higher importance of the radius of curvature with
respect to the angle of curvature of the root canal.
The CM-wire NiTi alloy endodontic reciprocating files exhibit a volumen wear
after clinical use.
Ultrasonic tips enable greater ease of removal of NiTi endodontic rotary files
from the root canal system, with similar amounts of dentin removal between the
two methods.
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