Comparative evaluation of cyclic fatigue fracture resistance of newer Ni Ti rotary files: An in vitro study

The single-file technique has been developed for shaping the vast majority of canals, regardless of their length, diameter, or curvature. Aim: This study compared the cyclic fatigue fracture resistance in canal after instrumentation with single file system and multiple file system i.e- One Curve, F360 (single file systems) and Neoendo (multiple rotary file).Method: Ten rotary instruments of each type and totalling 30 instruments of 25 mm in length were divided into 3 groups. Group 1: Neoendo, Group 2:F360, Group 3: One Curve. The dental hand piece was mounted on a mobile device that allowed for the simple placement of each instrument inside the artificial canal. To prevent the instruments from slipping out and to allow for observation of the instruments, the artificial canals were covered with glass. The time was then converted into number of cycles to failure. NCF = Number of rotations per minute x Time to fracture.Result: The mean values of time in seconds to fracture in F360 were lowest followed by Neoendo and highest was found in One Curve group.