Joo-Yeong Lee, DDS, MS,* Sang Won Kwak, DDS, MS, PhD,* Jung-Hong Ha, DDS, MS, PhD,† Ibrahim H. Abu-Tahun, DDS, PhD,‡ and Hyeon-Cheol Kim, DDS, MS, PhD*
Abstract Introduction:
The aim of this study was to compare the cyclic fatigue, torsional resistance, and bending stiffness of single-file glide path preparation nickel-titanium instruments. Methods: ProGlider (#16/progressive taper; Dentsply Sirona, Ballaigues, Switzerland), One G (#14/ .03; Micro-Mega, Besancon, France), and EdgeGlidePath (#16/progressive taper; Edge Endo, Albuquerque, NM) were tested. For the bending stiffness test, the instrument was bent to a 45 angle along the main axis while 3 mm of the tip was secured. Cyclic fatigue resistance was measured during pecking movement, whereas the file was rotated within a reproducible simulated canal with a 3-mm radius and a 90 angle of curvature. The ultimate torsional strength and toughness were evaluated using a custom device. While tightly holding the end of the file at 3 mm, a rotational load of 2 rpm speed was applied until fracture. The results were analyzed using 1-way analysis of variance and Tukey post hoc comparison. A microscopic inspection was performed on the surface of a separate instrument using a scanning electron microscope. Results: EdgeGlidePath showed superior cyclic fatigue resistance compared with the other systems. One G showed higher maximum torsional strength than the others. One G showed the largest distortion angle and the highest toughness followed by EdgeGlide- Path and ProGlider (P < .05). One G also showed larger bending stiffness than the others, whereas EdgeGlide- Path showed a larger residual angle than the others (P < .05). Conclusions: Conventional wire showed higher toughness and torsional resistance than M-Wire and heat-treated nickel-titanium instruments. However, heat-treated wire showed higher cyclic resistance than conventional wire and M-Wire. (J Endod 2019;45:199– 204)
