Structural effects of sodium hypochlorite solution on RaCe rotary nickel-titanium instruments: an atomic force microscopy study.
OBJECTIVE
The aim of this study was to investigate the effect of sodium hypochlorite immersion on the surface characteristics of RaCe rotary nickel-titanium instruments using atomic force microscopy (AFM).


METHODS
Four new RaCe instruments were used in this study (two 30.06 and two 30.02). One 30.06 and one 30.02 instrument were immersed in sodium hypochlorite solution for 5 min. Surface topography of the instruments was evaluated using the AFM. The instruments were analyzed on 11 points along a 3-mm section. Root mean square (RMS) values were used to compare the topographic deviations. The data were analyzed using Student t test.


RESULTS
Mean RMS values for NaOCl measurements were higher than the measurements on new files, and the difference was statistically significant (P < .01).


CONCLUSIONS
The AFM results show that NaOCl causes deterioration on the surface of RaCe instruments and should be used with care during clinical use because of the risk of unexpected failure.
Topuz
Ozgur
O
Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
Aydin
Cumhur
C
Uzun
Ozgur
O
Inan
Ugur
U
Alacam
Tayfun
T
Tunca
Yasar M
YM
D003343:Corrosion; D003722:Dental Alloys; D003762:Dental Instruments; D003799:Dental Stress Analysis; D004868:Equipment Failure; D018625:Microscopy, Atomic Force; D009532:Nickel; D012388:Root Canal Irrigants / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation*; D012973:Sodium Hypochlorite / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium
D003722:Dental Alloys; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium; D012973:Sodium Hypochlorite