title: Structural effects of sodium hypochlorite solution on RaCe rotary nickel-titanium instruments: an atomic force microscopy study.
abstract: 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.
authors.affiliation: Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
authors.forename: Ozgur
authors.initials: O
authors.lastname: Topuz
authors.forename: Cumhur
authors.initials: C
authors.lastname: Aydin
authors.forename: Ozgur
authors.initials: O
authors.lastname: Uzun
authors.forename: Ugur
authors.initials: U
authors.lastname: Inan
authors.forename: Tayfun
authors.initials: T
authors.lastname: Alacam
authors.forename: Yasar M
authors.initials: YM
authors.lastname: Tunca
mesh_terms: 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
chemical_list: D003722:Dental Alloys; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium; D012973:Sodium Hypochlorite