Mechanical properties of nickel-titanium endodontic instruments and the effect of sodium hypochlorite treatment

Rotary NiTi Instrument Fracture and its Consequences

“…However, it has been shown that NaOCl did not significantly reduce the torque at fracture or the number of revolutions to flexural fatigue of NiTi instruments (129) and was unlikely to cause pitting or crevice corrosion of NiTi instruments (130). Similarly, Haïkel et al (131) reported that mechanical properties of NiTi instruments were not affected by NaOCl, nor was the cutting efficiency (132). Nevertheless, at concentrations of 5 to 5.25%, NaOCl can lead to measurable corrosion (133).…”

Cyclic Fatigue Resistance of Three Different Nickel-Titanium Instruments after Immersion in Sodium Hypochlorite

“…The corrosive effect of NaOCl on endodontic NiTi instruments has been studied previously. Haikel et al (25) used hand instruments totally immersed in a 2.5% solution for 24 to 48 hours and detected no obvious corrosion. Busslinger et al (26) used 5% NaOCl for 30 or 60 minutes and Lightspeed rotary instruments and found corrosion patterns, even if the authors were not sure of the clinical implications (Discus Dental, Culver City, CA).…”

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

“…Other advantages associated with NiTi include its biocompatibility and high resistance to corrosion (4,5).…”