The application of the measurement of impedance to the corrosion of dental amalgams

A preliminary experimental investigation of the electrochemical characteristics of a high and a low copper dental amalgam in contact with saline solution has been carried out. The impedance and the corrosion current (in the absence of dissolved oxygen) have been measured at each potential in the near steady state for fresh amalgam surfaces. Analysis of the electrochemical data produces charge transfer resistance, double layer capacity, ohmic resistance and Warburg coefficient curves, which are briefly discussed. The aim of the work is, ultimately, to determine thein vivo corrosion rates and heavy metal ion release from amalgams.Nomenclature a anodic Tafel slope - C _dl differential capacity - D _A diffusion coefficient of A - E potential with respect to SCE electrode - E ₀ standard potential with respect to SCE - i current density - j square root of-1 - R ohmic loss resistance - R _cl charge transfer resistance - Z() impedance - frequency of a.c. potential - diffusion layer thickness - Warburg impedance parameter