Ultrastructure of the predentinal-dentinal border zone of human teeth exposed to basic chromium (III) sulfate. A method for contrasting of collagen fibrils.

An electron microscopic investigation was undertaken to study a method for contrasting predentine collagen fibrils by their cross-striations after exposure of tissue to chromium solution for various periods. After 1 day of treatment, the cross-striations of collagen fibrils in predentine were clearly visible. The contrast of the cross-striations increased with longer periods of exposure to chromium. This method makes it possible to study the orientation of crystallites as well as collagen fibrils.