The structure and function of the cemento-dentinal junction in human teeth.

The structure and function of the cemento-dentinal junction were studied in human molars by light and electron microscopy. The cemento-dentinal junction was an approximately 1-3-micron-thick layer full of proteoglycans with mucopolysaccharides but containing fewer collagen fibrils than the root dentin and cementum. In places, cemental fibrils crossed the cemento-dentinal junction. These fibrils appeared to intermingle with dentinal fibrils. By enzymatic treatment of decalcified specimen with hyaluronidase and trypsin, the cemento-dentinal junction decreased or lost staining affinity to toluidine blue. Prolonged treatment caused the separation of cementum from the root dentin during routine histological processes. These data suggest that the adhesion of proteoglycans is more important than the intermingling of dentinal and cemental fibrils for the cemento-dentinal attachment.