title: Hybrid framework with cobalt-chromium alloy and gold cylinder for implant superstructure: Bond strength and corrosion resistance.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate tensile bond strengths and corrosion resistance of CoCr alloys joined with gold cylinder by a soldering system in comparison with the conventional cast-joining system.
  
  
  METHODS
  CoCr alloys joined with gold cylinder by a soldering system using a high-fusing gold solder (CoCr/Solder/Gold cylinder), gold alloy joined with gold cylinder by a cast joining system (Gold alloy/Gold cylinder) and CoCr castings were fabricated. The tensile bond strength and corrosion resistance in 0.9% NaCl solution (pH 7.4 and pH 2.3) were evaluated. Scanning electron microscopy (SEM) of the fractured surface and electron probe microanalysis (EPMA) of the joined interfaces were also performed.
  
  
  RESULTS
  The tensile bond strengths of the CoCr/Solder/Gold cylinder specimens showed similar values as the Gold alloy/Gold cylinder specimens. SEM observation and EPMA analyses suggested firm bonding between the CoCr alloy and gold cylinder. The released elements from the CoCr/Solder/Gold cylinder specimens were similar to ones from CoCr castings.
  
  
  CONCLUSIONS
  Results showed that superstructures made of CoCr alloys joined with the gold cylinder using a high-fusing gold solder had sufficient bond strength and high corrosion resistance. These hybrid frameworks with cobalt-chromium alloy and gold cylinder are promising prosthesis for implant superstructures with the low cost and favorable mechanical properties instead of conventional high-gold alloys.
authors.affiliation: Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan. Electronic address: yosinari@tdc.ac.jp.
authors.forename: Masao
authors.initials: M
authors.lastname: Yoshinari
authors.affiliation: Reality Dental Laboratory, 2-3-22 Kudanminami, Chiyoda-ku, Tokyo 102-0072, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Uzawa
authors.affiliation: Brånemark Osseointegration Center Tokyo, 27-4 Ichibancho, Chiyoda-ku, Tokyo 102-0082, Japan.
authors.forename: Yataro
authors.initials: Y
authors.lastname: Komiyama
mesh_terms: D002858:Chromium Alloys; D001840:Dental Bonding; D003735:Dental Casting Technique; D015921:Dental Implants; D003764:Dental Materials; D012994:Dental Soldering; D003799:Dental Stress Analysis; D004577:Electron Probe Microanalysis; D006046:Gold; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013718:Tensile Strength
chemical_list: D002858:Chromium Alloys; D015921:Dental Implants; D003764:Dental Materials; D006046:Gold
keywords: Bond strength; Cobalt–chromium alloy; Corrosion resistance; Gold cylinder; Implant superstructure