Microradiography of human pulp tissue and decalcified coronal dentine

The X-ray absorption of decalcified, dehydrated sections of the coronal portion of human teeth (mainly young premolars) was evaluated in the light microscope. With the exception of the matrix at the dentine-enamel junction, the dentine exhibited a fairly uniform X-ray absorption. The predentine was separable into two layers with different X-ray absorptions; the peripheral layer was generally of the same radiopacity as the rest of the dentine, while the layer nearest the odontoblasts was more radiolucent. The matrix of secondary deposits of mineralized tissue showed a variable degree of radiopacity. The contents of the tubules were discernable in the pulpal part of the dentine. Neither intracellular nor intranuclear details could be demonstrated in the pulp tissue but cell nuclei, bundles of collagen, capillary walls and especially red blood cells were more radiopaque than intracytoplasmic- and intercellular substance.