Visualization of human predentin and hypomineralized areas of dentin by silver methenamine staining

The light microscopic structure of human teeth was studied following silver methenamine staining, with and without previous oxidation in periodic acid. Predentin, hypomineralized dentin and carious dentin stained intensely, whereas highly mineralized dentin and calcospherites at the predentin-dentin junction did not show any reactivity when observed in the light microscope, even following demineralization in strong acid or in EDTA. The reactive sites of the pulp were confined to nuclei, nucleoli and a few thin fibers. This distribution of reactive sites is different from the distribution which is seen following von Kossa's silver stain, and from the distribution seen following silver stain methods for reticular fibers.