Potentiodynamic polarisation technique for corrosion testing of Cr-Co and Cr-Ni alloys in artificial saliva and soft drinks

The corrosion of alloys used in dentistry affects the biological, functional and esthetic properties of the material. This study compares the corrosion behaviour of Cr-Co and Cr-Ni alloys used in restorative dentistry in four different types of solution (distilled water, orange nectar, cola and artificial saliva). Electrochemical polarisation experiments were performed using a potentiostat and carried out in a corrosion cell containing a solution of 500 mL at body temperature (37 degrees C). It can be seen from experimental results that Cr-Co alloy has lower corrosion current densities than Cr-Ni alloy. When the media effect is observed, corrosion current densities are higher for cola and orange juice, which have lower pH. As a result, Cr-Co alloys seem to be, from the biocompatibility point of view, more convenient in the intraoral use as dental alloys. In conclusion, corrosive potential of Cr-Ni alloy is statistically higher in cola drinks compared with juices.