Edson YanagaLuiz NacamuraEliane Bodanese
Sodium hypochlorite is a major irrigant in endodontics, and nickel-titanium instruments are gaining in popularity. This paper investigated the corrosion of nickel-titanium Lightspeed instruments in 1% and 5% NaOCl solutions. The instruments were immersed in ultrasonicated NaOCl solutions for varying times up to 1 h. Corrosion was determined by electrothermal absorption spectrometry in 100 microL aliquots of NaOCl. Background contamination of nickel in the 1% and 5% NaOCl solutions used was low, but high enough to interfere in detecting any increases in nickel after immersing the instruments. The amounts of titanium recorded in the 1% NaOCl solutions were insignificant. However, a statistically significant amount of titanium was detected from the Lightspeed instruments after immersion times of 30 and 60 min in 5% NaOCl. Clinically such instruments do not have an 'in situ' time of 30 min, and this corrosion may be considered irrelevant clinically.
David LewisThanassis Tiropanis
S. BrassellR.A. AchterbergF. AghdasiH.E. Hanrahan
F. VandermenlenJean-Marc ReyndersL. MissaPiet Demeester