[An electron paramagnetic resonance study of 4 salivary calculi treated in an ionized oxygen atmosphere].

Four salivary calculi and synthetically prepared hydroxyapatite, tricalcium phosphate and B-type carbonated fluorapatite or hydroxyapatite were treated under excited oxygen atmosphere. All these samples were studied by Electron Spin Resonance at 100 K. The presence of paramagnetic ozonide ions was observed only in the salivary calculi and in the hydroxyapatite. This indicates that the dominant apatite phase in salivary calculi is weakly carbonated hydroxyapatite.