Further Observations on Vital Staining of Dentin and Enamel

Abstract

The purpose of the investigation was to define fluid interchange between the pulp, dentin and enamel which might support slight metabolic processes. A total of 224 vitally stained teeth of man, dog, monkey, sheep, calf and cat were studied using not only AgNO3 but also water-soluble eosin, congo red, borax carmine, methylene blue, argyrol and K permanganate. The dry dyes were placed in cavities drilled in sound teeth of various ages and left in the mouths for from 6 min. to 4 wks. Prepared sections showed that the dyes were dissolved by a tissue fluid which has been named dental lymph and distributed through dentin and enamel establishing permeable channels in these tissues. In teeth from which the dental pulps had been removed recently, the dye no longer remained in the organized channels but diffused across them; the dentin and enamel showed a far greater degree of permeability than vital teeth. This observation, according to physiologists, shows that death had occurred in the dental tissues as a result of the removal of the pulp; hence a low degree of metabolism, dependent on the dental pulp is suggested in dentin and enamel, active for some time after tooth eruption. The fact that the dye, which had penetrated to the dental pulp, was redistributed by this organ, suggests that the dental lymph originates from the dental pulp. Argyrol and K, permanganate particles are transported in 2 directions, efferently and afferently in uninjured tubules which may explain one phase of dentin metabolism.