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Published on: February 20, 2020
Comparison of cyclic fatigue resistance of used and new RaCe instruments
Cumhur Aydin1, Ugur Inan, Yasar M Tunca
1Department of Endodontics and Conservative Treatment, Center for Dental Sciences, Gulhane School of Medicine, Ankara, Turkey. cumhuraydin@hotmail.com
Objective:
The aim of this study was to evaluate cyclic fatigue resistance of used and new RaCe rotary nickel-titanium instruments.
Study Design:
Forty RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) instruments of sizes 30/.06, 30/.02, 25/.04, and 25/.02 were selected and divided into 2 groups: group A = 20 new instruments; group B = 20 used instruments. In group B, each instrument was used for shaping 5 curved molar root canals. Cyclic fatigue testing of new and used instruments was performed using a device that allowed the instruments to rotate freely inside a stainless steel artificial canal. Data were analyzed using t test to determine any statistical significance between used and new instruments of the same file size.
Results:
For all sizes, new instruments were more resistant to failure then the used ones (P < .05). A reduction in lifespan was observed ranging from 18% (30/.06) to 51% (25/.02).
Conclusion:
The results showed that clinical use significantly reduced cyclic fatigue resistance of RaCe rotary instruments compared with new ones.
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