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  • Küçük Resim
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    Cyclic fatigue resistances of Hyflex EDM, WaveOne gold, Reciproc blue and 2shape NiTi rotary files in different artificial canals
    (Springer, 2018) Özyürek, Taha; Gündoğar, Mustafa; Uslu, Gülşah; Yılmaz, Koray; Staffoli, Simone; Grande, N. M.; Plotino, Gianluca; Polimeni, Antonella
    The aim of the present study was to compare the cyclic fatigue resistances of HyFlex EDM (HEDM), WaveOne Gold (WOG), Reciproc Blue (RB), and 2Shape (TS) NiTi systems having different metallurgic properties. HEDM, WOG, RB, and TS instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5mm, 45 degrees, and 90 degrees angles of curvatures and a radius of curvature of 5mm until fracture occurred, and the time to fracture (TTF) was recorded in seconds. Also, number of cycles to fracture was calculated (NCF). Data were statistically analyzed using Kruskal-Wallis and t test. The statistical significance level was set at P<0.05. When comparing the TTF of all the instruments tested in the artificial canal with 45 degrees curvature, RB had statistically the highest cyclic fatigue resistance followed by HEDM and TS (P<0.05), while the WOG showed the lowest cyclic fatigue resistance (P<0.05). In artificial canal with 90 degrees curvature, RB showed a significantly higher cyclic fatigue resistance than the other tested files (P<0.05), while there was no significant difference among the TS, WOG and HEDM groups (P>0.05). When the NCF values were taken into consideration, HEDM reported a significantly higher cyclic fatigue resistance than TS in both canal curvatures analyzed (P<0.05). Within the limitations of the present study, RB NiTi files showed statistically higher cyclic fatigue resistance in artificial canals with 45 degrees and 90 degrees than the other NiTi files tested.
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    Öğe
    Influence of environmental temperature, heat-treatment and design on the cyclic fatigue resistance of three generations of a single-file nickel-titanium rotary instrument
    (Springer, 2019) Staffoli, Simone; Grande, Nicola Maria; Plotino, Gianluca; Özyürek, Taha; Gündoğar, Mustafa; Fortunato, Leonzio; Polimeni, Antonella
    The aim of the present study was to evaluate the effect of environmental temperature, heat-treatment*** and design on the cyclic fatigue resistance of OneShape (OS), OneShape new generation (OSNG) and One Curve (OC) NiTi rotary single-file instruments. Cyclic fatigue testing of NiTi instruments was performed in an artificial canal with a 5-mm radius of curvature and a 60 degrees angle of curvature located 5mm from the tip of the instrument. During the experiment 3 different temperatures were used in a thermostatic bath with electronic and infrared controls: 0 degrees, 20 degrees and 35 degrees C. Sixty OneShape, 60 OneShape new generation and 60 One Curve instruments were rotated in the artificial canal until fracture occurred and the number of cycles to fracture (NCF) and the length of the fractured fragment (FL) was recorded. Data were analyzed by one-way ANOVA test at the 5% significance level. Fatigue resistance was significantly higher as the environmental temperature decreased, with differences ranging from 61 to 791%. OC instruments were significantly more resistant to cyclic fatigue than OS and OSNG instruments at all the temperatures tested (P<0.05). There was no significant difference with respect to the length of the fractured file fragments for all the instruments tested at all the temperatures tested (P>0.05). Within the limitation of the present study, fatigue resistance of the files was significantly increased when the environmental temperature decreased. OC instruments were significantly more resistant to cyclic fatigue than OS and OSNG instruments at all the temperatures tested.