title: Diamondlike carbon coating as a galvanic corrosion barrier between dental implant abutments and nickel-chromium superstructures.
abstract: OBJECTIVE
  The objectives of this study were to evaluate the galvanic corrosion behavior between titanium and nickel-chromium (Ni-Cr) alloy, to investigate the effect of diamondlike carbon (DLC) coating over titanium on galvanic corrosion behavior between titanium and Ni-Cr alloy, and to evaluate the effect of DLC coating over titanium abutments on the fit and integrity of prosthetic assemblies by scanning electron microcopy (SEM).
  
  
  METHODS
  Five Ni-Cr and 10 titanium disks with a diameter of 5 mm and thickness of 3 mm were prepared. DLC coating was applied to five titanium disks. Electrode samples were prepared, and open circuit potential measurements, galvanic current measurements over platinum electrodes, and potentiodynamic polarization tests were carried out. For the SEM evaluation, 20 Ni-Cr alloy and 10 gold alloy superstructures were cast and prepared over 30 abutments. DLC coating was applied to 10 of the abutments. Following the fixation of prosthetic assemblies, the samples were embedded in acrylic resin and cross sectioned longitudinally. Internal fit evaluations were carried out through examination of the SEM images.
  
  
  RESULTS
  Titanium showed more noble and electrochemically stable properties than Ni-Cr alloy. DLC coating over the cathode electrode served as an insulating film layer over the surface and prevented galvanic coupling. Results of the SEM evaluations indicated that the DLC-coated and titanium abutments showed no statistically significant difference in fit. Hence, no adverse effects on the adaptation of prosthetic components were found with the application of DLC coating over abutment surfaces.
  
  
  CONCLUSIONS
  DLC coating might serve as a galvanic corrosion barrier between titanium abutments and Ni-Cr superstructures.
authors.affiliation: Department of Prosthodontics, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil. aozkomur@yahoo.com
authors.forename: Ahmet
authors.initials: A
authors.lastname: Ozkomur
authors.forename: Mehmet
authors.initials: M
authors.lastname: Erbil
authors.forename: Tolga
authors.initials: T
authors.lastname: Akova
mesh_terms: D002244:Carbon; D002858:Chromium Alloys / Q000737:chemistry; D020099:Coated Materials, Biocompatible; D003343:Corrosion; D000044:Dental Abutments; D003722:Dental Alloys / Q000737:chemistry*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D006047:Gold Alloys / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D014025:Titanium / Q000737:chemistry*
chemical_list: D002858:Chromium Alloys; D020099:Coated Materials, Biocompatible; D003722:Dental Alloys; D015921:Dental Implants; D006047:Gold Alloys; D002244:Carbon; D014025:Titanium