title: Cyclic fatigue of ProFile rotary instruments after clinical use.
abstract: OBJECTIVE
  The purpose of this study was to evaluate cyclic fatigue of .06 ProFile Ni-Ti rotary instruments after clinical use in molar teeth.
  
  
  METHODS
  In group 1, instruments size 40-15 were used in a crown-down technique using 2.5% NaOCl as an irrigant. Fifty-two molars were included and 13 sets of Profile Ni-Ti rotary instruments were used. Each set of instruments was used in four molars, and was steam autoclaved before each use. Group 2 (10 sets of new ProFile Ni-Ti rotary instruments) was the control group. Cyclic fatigue was tested by rotating the instruments in a 90 degrees metallic tube until they broke.
  
  
  RESULTS
  One-way analysis of variance did not show any statistically significant differences amongst the files from both groups regarding cyclic fatigue.
  
  
  CONCLUSIONS
  It was concluded that sterilization and clinical use in the presence of NaOCl did not lead to a decrease in the number of rotations to breakage of the files.
authors: Department of Endodontics, Lebanese University, Lebanon. k1000@tmi.com.lb
authors: G M
authors: GM
authors: Yared
authors: F E
authors: FE
authors: Bou Dagher
authors: P
authors: P
authors: Machtou
mesh_terms: D000704:Analysis of Variance; D003754:Dental High-Speed Equipment; D003762:Dental Instruments; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D008963:Molar; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D014025:Titanium
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium