title: Ceramic bonding to a machined Au-Ti alloy.
abstract: OBJECTIVE
  To assess in vitro the bond strength of a machined surface of a Au-Ti alloy to a veneering ceramic.
  
  
  METHODS
  Metal strips of the alloy Au 1.7-Ti 0.1-Ir were milled from a semiproduct fabricated by continuous casting and cold forming. For comparison, the same alloy as well as a traditional Au-Pt-Pd-In alloy were used in the as-cast state. Six samples of each group were fabricated for the crack initiation test, according to ISO 9693:1999, by preparing appropriate metal strips that were veneered with ceramic using a standard firing procedure. The crack initiation test was performed in a universal testing machine. Load at fracture was recorded. Means of bond strength were calculated for each group and the results compared by use of a 1-sided Student t test (P < .05). Fracture sites were documented by means of SEM.
  
  
  RESULTS
  Bond strength in the 3 groups was in the same order of magnitude. Failure mode was different for both alloys. Failure of the bonding to the Au-Ti alloy predominantly occurred at the alloy-oxide interface, no matter which fabrication process was used. On the Au-Pt-Pd-In alloy, more ceramic residues were observed.
  
  
  CONCLUSIONS
  The machined alloy Au 1.7-Ti 0.1-Ir provides sufficient bond strength to veneering ceramics, but this has to be proven by a clinical study.
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Berne, Berne, Switzerland.
authors.forename: Rolf K
authors.initials: RK
authors.lastname: Kellerhoff
authors.forename: Jens
authors.initials: J
authors.lastname: Fischer
mesh_terms: D003722:Dental Alloys; D001840:Dental Bonding; D003735:Dental Casting Technique; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D003801:Dental Veneers; D006047:Gold Alloys; D008422:Materials Testing; D016876:Metal Ceramic Alloys
chemical_list: D003722:Dental Alloys; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; C416206:gold-titanium alloy; D003776:Dental Porcelain