Cyclic Fatigue Resistance and Force Generated by OneShape Instruments during Curved Canal Preparation

Abstract

ObjectivesTo evaluate the cyclic fatigue resistance and the force generated by OneShape files during preparation of simulated curved canals.MethodsSix OneShape files (the test) and six ProTaper F2 files (the control) were subject to the bending ability test. Another thirty files of each type were used to prepare artificial canals (n = 60), which were divided into 3 groups according to respective curvatures of the canals (30°, 60°, and 90°). The numbers of cycles to fatigue (NCF) as well as the positive and negative forces that were generated by files during canal preparation were recorded. The scanning electron microscopy was applied to detect the fracture surfaces.ResultsCompared with ProTaper F2 files, the bending loads of OneShape files were significantly lower at deflections of 45°(P < .05), 60° (P < .05) and 75° (P < .01). No significant difference was found at 30°. OneShape files presented a higher NCF in both 60° and 90° canals than the control (P < .01). No significant difference of NCF was found between OneShape and ProTaper files in 30° canals. During the preparation of 30° canals by both files, the negative forces were dominant. With the increase of the curvature, more positive forces were observed. When the OneShape Files were compared with the control, significant different forces were found at D3 and D2 (P < .05) in 30° canals, at D2 (P < .05), D1 (P < .01) and D0 (P < .01) in 60° canals, and at D4 and D3 (P < .01) in 90° canals.ConclusionsOneShape files possessed a reliable flexibility and cyclic fatigue resistance. According to the assessments of the forces generated by files, OneShape instruments performed in a more fatigue-resistant way during curved canal preparation, compared with the ProTaper F2 files.

Prediction of thrust force and torque in canal preparation process using Taguchi method and Artificial Neural Network

“…The increase in the curvature of the root canal will result in a dramatic change in the thrust force, which reaches the same conclusion as other researches. 24,25 At the same time, as we can see from Figure 6(c), the increase of diameter and feed rate have led to an increase of torque. But, with the increase of width of root canal, the torque has decreased.…”

Static Flexural Cyclic Fatigue of Two Rotary File Systems (An in Vitro Study)

“…In the contrary, Wang et al, (38) found that OneShape files had higher cyclic fatigue resistance than ProTaper Universal (F2) files when files tested in canals with 60° and 90° angle of curvature.…”