The metal-ceramic fixed prosthetic restoration which reestablish the continuity of dental arches  are widely used in dentistry.
The alloys features needed for in metal-ceramic technology [2-4] are:
- high temperature resistance, which allow for no deformation during ceramics firing;
- melting temperature must be lower than 1300°C for an easy processing, and should be higher with about 150…200°C than sintering temperature interval of the ceramics which is in the range 850…1100°C;
- thermal expansion coefficient should be closed to the one of ceramic mass, to avoid share stress appearance in the interface alloy-ceramic durring prosthetic piece cooling;
- solidification shrinkage should be less than 2.5%;
- yield strength should be as high as possible;
- should allow on optimal adherence of the ceramics mass.
Dental materials interact with living tissues they come in contact with and generate local or systemic responses . The biocompatibility of dental alloys is important and is considered a controversial problem for practitioner physicians .
Among the causes of metal-ceramic restorations failure are cited in literature: degradation by corrosion of alloys, mechanical wear and fatigue fracture [7-9].
Corrosion is described as the destruction or damage of the material under the action of aggressive environment (atmosphere and oral fluids) .
Metal alloys based on Chromium and Cobalt are widely used in the dentistry field .
The Co-Cr or Ni-Cr alloys have good corrosion comportment because of Chromium presence, which forms a stable chromium oxide layer on the alloy surface [12-18]. In addition, the allergenic potential of Cr-Co based dental alloys is very small compared with the allergenic potential of the dental alloys based on Ni-Cr  in patients with allergic ground.