title: The effect of sodium hypochlorite on the surface characteristics and fatigue resistance of ProFile nickel-titanium instruments.
abstract: OBJECTIVE
  Evaluate the effect of 5.25% NaOCl on the surface characteristics and fatigue resistance of ProFile.
  
  
  METHODS
  Eighty new ProFile instruments were divided into 1 control group (CG) and 3 experimental groups (EG1, EG2, EG3). Instruments of EG1 were immersed in 5.25% NaOCl for 24 hours. Instruments of EG2 and EG3 shaped 10 curved root canals, using, respectively, deionized water and 5.25% NaOCl as irrigants. Surface characteristics were observed by scanning electron microscopy. All instruments were then submitted to fatigue tests. Two-way ANOVA tests were employed to compare the results.
  
  
  RESULTS
  Surface characteristics showed no alteration after the immersion tests. The fatigue resistance of instruments in EG2 and EG3 was significantly lower than in CG and EG1.
  
  
  CONCLUSIONS
  Immersion of ProFile in 5.25% NaOCl for 24 hours had no influence on surface characteristics and fatigue resistance. Simulated clinical use was a decisive factor in the decrease of fatigue life.
authors.affiliation: Department of Metallurgical and Materials Engineering, Engineering School, Federal University of Minas Gerais, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: de Castro Martins
authors.forename: Maria Guiomar A
authors.initials: MG
authors.lastname: Bahia
authors.forename: Vicente T L
authors.initials: VT
authors.lastname: Buono
authors.forename: Belo
authors.initials: B
authors.lastname: Horizonte
mesh_terms: D000704:Analysis of Variance; D003343:Corrosion; D003722:Dental Alloys; D003762:Dental Instruments; D003799:Dental Stress Analysis; D004868:Equipment Failure; D017743:Equipment Reuse; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009532:Nickel; D012388:Root Canal Irrigants; D018915:Root Canal Preparation / Q000295:instrumentation*; D012973:Sodium Hypochlorite; D013499:Surface Properties; D014025:Titanium
chemical_list: D003722:Dental Alloys; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium; D012973:Sodium Hypochlorite