Comparison of Mechanical and Structural Properties of Nickel-titanium Alloy with Titanium-molybdenum Alloy and Titanium-niobium Alloy as Potential Metals for Endodontic Files

 The objective of this study was to compare the mechanical and structural properties of the nickel-titanium (Ni-Ti) alloy already used in endodontics with titanium-molybdenum (Ti-Mo) and titanium-niobium (Ti-Nb) alloys to determine if these can be suggested in the manufacture of endodontic files. Methods and Materials: Orthodontic wires made of the different alloys were used. The previously mentioned alloys were characterized by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and torsion tests. Cyclic fatigue tests were performed on a simulated canal with a curvature of 86° to 375 rpm. The fractured surfaces of the wires were observed by means of scanning electron microscopy (SEM). A Kruskal-Wallis test and U Mann Whitney test were used to determine significant differences in cyclic fatigue between groups. 

 In the mechanical tests, similar values of torsion were found for the three alloys. In XRD, the Ti-Nb showed less structural changes. In the cyclic fatigue test, Ti-Nb was found to be significantly more resistant with respect to Ni-Ti and Ti-Mo. 

 Based on our in vitro study, Ti-Nb is suggested as a possible alloy for the manufacture of rotary files due to its impressive properties.