title: Mathematical modeling of flexural behavior of rotary nickel-titanium endodontic instruments.
abstract: The aim of the present study was to establish a mathematical model to characterize the flexural behavior of nickel-titanium (NiTi) rotary instruments. The bending behavior of ProFile (0.06 and 0.04 tapers), K-3 (0.06 taper), Quantec (0.04 taper) with tip size of ISO 25, was assessed by pressing the tip of the static rotary file against a smooth, freely movable, glass surface. The deflected instrument was photographed digitally, and the deflection path was digitized in software, to which data a function was fitted that best described the bending behavior of the instrument. It was found that all instruments deflected in a manner closely resembling a negative exponential function: y = A x e(-x/b). The present approach indicated that the analytical difficulties of handling the complex cross-section in tapering spirals in beam-bending theory may be circumvented by a practical and elementary curve-fitting method.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, The University of Hong Kong, Pokfulam, Hong Kong. dannylow@scientist.com
authors.forename: Danny
authors.initials: D
authors.lastname: Low
authors.forename: Angela W L
authors.initials: AW
authors.lastname: Ho
authors.forename: Gary S P
authors.initials: GS
authors.lastname: Cheung
authors.forename: Brian W
authors.initials: BW
authors.lastname: Darvell
mesh_terms: D003754:Dental High-Speed Equipment; D004548:Elasticity; D008962:Models, Theoretical; D009532:Nickel / Q000737:chemistry; D012390:Root Canal Therapy / Q000295:instrumentation*; D012399:Rotation; D014025:Titanium / Q000737:chemistry
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium