A phenomenological interpretation of the frequency-dependent impedance behaviour of bovine dental enamel.
The permeability of dental enamel can be estimated by means of diffusion measurements with radio-isotopes. Because of the low intrinsic permeability of enamel membranes, determination via this route may take two weeks. A much faster electrochemical method is presented, in which the real and imaginary part of the membrane impedance are measured at discrete intervals in the frequency-range 1 Hz-1 MHz. Using the principles of network-analysis, a phenomenological interpretation of these electrochemical data in terms of a 6-parameter model is given. The model contains R0, the intrinsic membrane resistance, R infinity, the residual membrane resistance and the four parameters, necessary to describe the postulated enamel diffusion impedance, which bears strong resemblance to the Warburg impedance. Starting from this model, optimal estimates (with standard-errors) of a membrane's R0 and vmax (the log of the frequency where the imaginary part of the membrane impedance is maximal) were derived. These parameters were predictors of the permeability of enamel.
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000502:physiology; D003743:Dental Enamel / Q000502:physiology*; D004058:Diffusion; D004553:Electric Conductivity; D008954:Models, Biological; D013997:Time Factors; D014088:Tooth Permeability