AN EPR STUDY OF INTACT AND POWDERED HUMAN TOOTH ENAMEL DRIED AT 400-DEGREES-C

An EPR study of human tooth enamel dried at 400 degrees C is presented . Enamel blocks as well as powdered samples were investigated. The dis cussion deals mainly with three different spectral components, i.e., a CO33- and two different CO2- signals. Using the anisotropic enamel bl ock spectra, a convincing differentiation between the latter two radic als was possible. The first CO2- signal shows no dependence on the ori entation of the enamel blocks, disappears from the spectrum upon heati ng, and was assigned to a surface radical. The second CO2- component i s mainly responsible for the angular variation of the enamel blocks an d is assigned to a bulk position. For the CO33- ion, the (pseudo) angu lar variation of its isolated spectrum is presented and discussed. By means of the results presented in this study, earlier interpretation p roblems are considerably reduced.