Cyclic Fatigue Resistance of Rotary Nickel-Titanium Instruments Submitted to Nitrogen Ion Implantation

Cyclic Fatigue Resistance of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals

“…Cyclic fatigue testing was performed with a custommade cyclic fatigue testing apparatus (12), specifically designed to allow dynamic testing and made essentially of aluminum (Fig. 1).…”

Morphological alterations of rotary nickel-titanium protaper® instruments analyzed by SEM: effect of nitrogen ion implantation

“…Given the variations in form, length, and anatomy of human root canals, many studies have opted to use extracted human teeth to produce more clinically faithful results [16]. However, despite the benefits of this approach, other studies [5][6][7][8][9][10][11][12] chose to use simulated canals, which allow for a level of standardization that cannot be obtained using extracted human teeth [17]. Moreover, epoxy-resin simulated root canals are similar to human dentin in hardness, enabling extrapolation of the experimental results to clinical practice [18].…”

“…Although the introduction of nickel-titanium (NiTi) instruments seemed to overcome this difficulty [1], the preparation of curved root canals results in morphological alterations, including wear, disappearance of the cutting edge, microfractures, and surface defects, to the instrument surface [2][3][4][5][6][7]. New surface treatment methods, such as ion implantation and plasma nitriding, have been investigated to improve the properties of these instruments and extend their life [8][9][10][11][12].…”

“…Most studies of nitrogen ion implantation have investigated implantation at doses of ~10 17 nitrogen ions/cm² [8][9][10][11][12]. In these studies, ion implantation produced better outcomes compared to nitrided or untreated instruments [8][9][10][11][12].…”

“…In these studies, ion implantation produced better outcomes compared to nitrided or untreated instruments [8][9][10][11][12]. Nitrogen ion implantation creates a layer of titanium nitride on the surface of components by using a low-energy accelerator (~100 to 400 keV) to bombard the NiTi surface with nitrogen ions [12].…”