Cyclic fatigue of two different single files with varying kinematics in a simulated double-curved canal.
OBJECTIVE
To evaluate and compare the cyclic fatigue of a rotary (One Shape) and reciprocating (Reciproc) single file system in a simulated S-shaped canal in static and dynamic models.


METHODS
The instruments (n = 50 per instrument) were tested in a custom-made device under static (n = 25) and dynamic loads (n = 25) to determine the number of cycles to fracture (NCF). The length of the fractured segments was also measured. Cyclic fatigue data were analyzed by one-way analysis of variance and Tukey honestly significantly different tests, while the data recorded for the fractured fragment lengths were compared using Student's t-test with the level of significance set at 0.05.


RESULTS
The fatigue life of Reciproc was significantly higher in the static (coronal curvature: 717.60 ± 45.32 NCF; apical curvature: 621.80 ± 60.15 NCF) and dynamic models (coronal curvature: 972.40 ± 54.30 NCF, apical curvature: 897.70 ± 47.10 NCF) as compared with One Shape (P < 0.05). The fatigue life was significantly prolonged in the dynamic model for Reciproc (P < 0.05) as compared to One Shape (P > 0.05).


CONCLUSIONS
The results of the present study showed that the single file reciprocating system (Reciproc) had a longer fatigue life than the single file rotary system (One Shape).
Biofilm Research Cluster, Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India.
Prasanna
P
Neelakantan
Army College of Dental Sciences, Secunderabad, India.
Pallavi
P
Reddy
Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX, USA.
James L
JL
Gutmann
D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D018915:Root Canal Preparation / Q000295:instrumentation*; D013314:Stress, Mechanical
canal anatomy; cyclic fatigue; nickel-titanium; reciprocation; rotary; stress