title: The elastic limit of nickel-containing and nickel-free cobalt-chromium circumferential clasp arms.
abstract: The purpose of this study was to compare the flexibility and rigidity of the retentive arms of cast circumferential clasps prepared from two nickel-containing alloys (Vitallium and Wironit) with a nickel-free alloy (Biosil). Standardised wax patterns were adapted to 30 specially prepared refractory casts. Ten of these waxed casts were sent to each of three commercial laboratories that specialize in making castings from each of the alloys to be tested. A tensile tester was used to test each one of the finished clasps for deflection at the elastic limit and for load at 0.5 mm deflection. An exploratory analysis of the data by means of a multivariate analysis of variance was followed by Fisher's least significant test that identified specific differences between test specimens. It was found that nickel-containing and nickel-free alloys were not significantly different in respect of flexibility and rigidity.
authors.affiliation: Department of Prosthetic Dentistry, School of Oral Health Sciences, University of the Witwatersrand, P.O. Wits, 2050, Johannesburg.
authors.forename: A R
authors.initials: AR
authors.lastname: Essop
authors.forename: L M
authors.initials: LM
authors.lastname: Sykes
authors.forename: J F
authors.initials: JF
authors.lastname: Wolfaard
authors.forename: H D
authors.initials: HD
authors.lastname: Chandler
authors.forename: P J
authors.initials: PJ
authors.lastname: Becker
mesh_terms: D002858:Chromium Alloys / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry; D003734:Dental Casting Investment / Q000737:chemistry; D016734:Dental Clasps; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D015999:Multivariate Analysis; D009532:Nickel / Q000737:chemistry*; D018583:Pliability; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D014800:Vitallium / Q000737:chemistry
chemical_list: C472722:Biosil; D002858:Chromium Alloys; D003734:Dental Casting Investment; C472721:Wironit; D014800:Vitallium; D003035:Cobalt; D009532:Nickel