title: Influence of structure on nickel-titanium endodontic instruments failure.
abstract: The purpose of this work was to investigate the process history on fracture life of nickel-titanium endodontics files. The results are based on microstructural investigations of nickel-titanium engine-driven rotary instruments based on X-ray diffraction, scanning electron microscopy, and microhardness tests. Endodontic files are very work-hardened, and there is a high density of defects in the alloy that can disturb the phase transformation. The microhardness Vickers confirmed these observations (dislocations and precipitates). The X-rays show that experimental spectrum lines are extended, typical of a distorted lattice. The surface state of the endodontic files (scanning electron microscopy) is an important factor in failure and fracture initiation.
authors.affiliation: UFR d' Odontologie, Paris, France.
authors.forename: G
authors.initials: G
authors.lastname: Kuhn
authors.forename: B
authors.initials: B
authors.lastname: Tavernier
authors.forename: L
authors.initials: L
authors.lastname: Jordan
mesh_terms: D003722:Dental Alloys / Q000737:chemistry*; D003755:Dental High-Speed Technique; D003762:Dental Instruments; D003799:Dental Stress Analysis; D004548:Elasticity; D004868:Equipment Failure; D006244:Hardness; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium