Evidence for Reduced Fatigue Resistance of Contemporary Rotary Instruments Exposed to Body Temperature.
ORCiD
Dr. Ove A. Peters: 0000-0001-5222-8718
Department
Endodontics
Document Type
Article
Publication Title
Journal of Endodontics
ISSN
0099-2399
Volume
42
Issue
5
DOI
10.1016/j.joen.2016.01.025
First Page
782
Last Page
787
Publication Date
5-1-2016
Abstract
INTRODUCTION: The purpose of this study was to evaluate the effect of 2 different temperatures (20°C and 37°C) on the cyclic fatigue life of rotary instruments and correlate the results with martensitic transformation temperatures.
METHODS: Contemporary nickel-titanium rotary instruments (n = 20 each and tip size #25, including Hyflex CM [Coltene, Cuyahoga Falls, OH], TRUShape [Dentsply Tulsa Dental Specialties, Tulsa, OK], Vortex Blue [Dentsply Tulsa Dental Specialties], and ProTaper Universal [Dentsply Tulsa Dental Specialties]) were tested for cyclic fatigue at room temperature (20°C ± 1°C) and at body temperature (37°C ± 1°C). Instruments were rotated until fracture occurred in a simulated canal with an angle curvature of about 60° and a radius curvature of 3 mm; the center of the curvature was 4.5 mm from the instrument tip. The number of cycles to fracture was measured. Phase transformation temperatures for 2 instruments of each brand were analyzed by differential scanning calorimetry. Data were analyzed using the t test and 1-way analysis of variance with the significance level set at 0.05.
RESULTS: For the tested size and at 20°C, Hyflex CM showed the highest resistance to fracture; no significant difference was found between TRUShape and Vortex Blue, whereas ProTaper Universal showed the lowest resistance to fracture. At 37°C, resistance to fatigue fracture was significantly reduced, up to 85%, for the tested instruments (P < .001); at that temperature, Hyflex CM and Vortex Blue had similar and higher fatigue resistance compared with TRUShape and ProTaper Universal.
CONCLUSIONS: Under the conditions of this study, using a novel testing design, immersion in water at simulated body temperature was associated with a marked decrease in the fatigue life of all rotary instruments tested.
Recommended Citation
de Vasconcelos, R. A.,
Murphy, S.,
Carvalho, C. A.,
Govindjee, R. G.,
Govindjee, S.,
&
Peters, O. A.
(2016).
Evidence for Reduced Fatigue Resistance of Contemporary Rotary Instruments Exposed to Body Temperature..
Journal of Endodontics, 42(5), 782–787.
DOI: 10.1016/j.joen.2016.01.025
https://scholarlycommons.pacific.edu/dugoni-facarticles/359
