Column-like structures following the course of dentinal tubules in bovine, red deer, and rat teeth

A material of bovine, red deer, and rat incisors was investigated, with emphasis on the bovine teeth. Both ground sections and paraffin wax sections of demineralized material were used. The sections were investigated by ordinary and polarized light microscopy and contact microradiography. In the bulk of the dentin irregular column-like light structures, alternating with largely similar, but dark, columns, followed the course of the dentinal tubules from the pulpal border to just below the mantle dentin. Each column, 10-100 micron in diameter, contained a highly varying number of tubules. The difference between light and dark columns was mainly related to the intertubular dentin of the globules of which they were composed. Light columns were slightly more mineralized than the dark ones and seemed to contain fewer GAGs, but more glycoproteins. A difference in fiber direction between light and dark columns was also evident. To the authors' knowledge these structures have not attracted the attention of previous workers.