A 42 year old female patient wants to get her missing tooth replaced but does not want to get dental implants placed. Intra-oral examination reveals a missing 46. 45 and 47 were prepared to receive a 3 unit fixed dental prosthesis. The prosthesis has a yellowish hue. The material used for the fabrication of the prosthesis could be all of the following alloys, except:

The compositions of casting alloys determine their color. Alloys with a relatively high gold content are yellow in hue and those containing significant concentrations of copper are reddish-yellow in hue. Most cast dental alloys, which are based on either cobalt, nickel, palladium, or silver, are “white” or silver in appearance. In general, if the palladium content is over 10 wt%, the alloy will be white. Thus the Pd-Cu-Ga and Ag-Pd alloys in the table below are white, whereas the other alloys are yellow (gold). The Au-Ag-Pd-In alloys are an exception because they have palladium content over 20% and retain a light yellow color. The color of this alloy results from an optical effect involving the interactions of the indium with the palladium in the alloy. Examples of such alloys are Argenco Y+ and Castell.