Evaluation of ion release from two base-metal alloys at various pH levels

We examined the influence of salivary pH on the corrosion of two base-metal alloys. Cobalt-chromium (Co-Cr) and nickel-chromium (Ni-Cr) alloy samples were created and submerged in artificial saliva of different pH values (pH 4, pH 5 and pH 7). The amount of each ion present in solution 1 month later was measured by flame atomic absorption spectrophotometry. Statistical analysis showed that pH significantly affected total and Co ion release, but not Ni or Cr ion release. The alloy type did not affect total ion release, but was significant for Cr ion release. Alloy-pH interaction significantly affected Cr and total ion release. To prevent metal particle release, the alloys used for dental restoration should, whenever possible, be made from noble metals and corrosion-resistant alloys.