Penetration of Radioactive Isotopes through Enamel and Dentin. I. Diffusion of Na²² in Fresh and Coagulated Dental Tissues

¹ Departments of Oral Histopathology and Biophysics, University of Umeå, Sweden, and the Harvard School of Dental Medicine, Boston, Massachusetts

The diffusion of Na²² in untreated and boiled dental hard tissues has been studied in intact, homologous premolars. The boiling, and hence the coagulation, had a marked effect on the diffusibility of these tissues, which was reduced. This reduction probably did not depend on a growth of the hydroxyapatite crystallites but seemed to be due to a coagulating effect on the soft tissues of the crown, including the so-called organic stroma of enamel and dentin. The reduced permeability of the boiled tissues was thought to be effected through a denaturation of the protein-mucopolysaccharide complex, which in vivo might be at least partly in gel form. In this case, the denaturation was caused by boiling.