title: Relationship between file size and stiffness of nickel titanium instruments.
abstract: The purpose of this study was to evaluate the relationship existing between file size and stiffness for 3 endodontic files made of nickel titanium. Three groups of instruments with different cross-sections were tested: a triangular cross-section, a square cross-section and a modified triangular cross-section. The instruments were tested from size 15 to size 40 or 60 according to ANSI/ADA specification no. 28 for binding moment evaluation. There was a statistically significant difference between the 3 groups: the square cross-section K files presented a larger bending moment than the triangular cross-section K files, which presented a larger bending moment than the modified cross-section K files. Like the stainless steel instruments, there was an exponential relationship between file size and bending moment for triangular and square cross-section K files, but a linear relationship between file size and bending moment for the files with a modified triangular cross-section.
authors.affiliation: Department of Restorative Dentistry and Endodontics, University of Marseille, France.
authors.forename: J J
authors.initials: JJ
authors.lastname: Camps
authors.forename: W J
authors.initials: WJ
authors.lastname: Pertot
authors.forename: B
authors.initials: B
authors.lastname: Levallois
mesh_terms: D000704:Analysis of Variance; D003799:Dental Stress Analysis; D004867:Equipment Design; D016018:Least-Squares Analysis; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry*; D018583:Pliability; D018915:Root Canal Preparation / Q000295:instrumentation*; D018709:Statistics, Nonparametric; D014025:Titanium / Q000737:chemistry*
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium