Structure and Development of the Peritubular Matrix in Dentin

¹ Department of Pathology, Tokyo Dental College, Kanda-Misakicho, Chiyoda-ku, Tokyo, Japan

The peritubular matrix in human developing and mature dentin was studied by means of microradiography, histochemistry, and electron microscopy. The sclerosed root dentin seen in aged teeth was also observed.

The presence of the peritubular matrix was confirmed in root dentin, as well as in crown dentin, from its formative stage. In root dentin, however, the peritubular matrix was generally small and apparently missing in some instances.

The organic base of the peritubular matrix was determined to be morphologically amorphous and to contain a large amount of acid mucopolysaccharides. This organic base was especially dense at the marginal portion of the dentinal tubules where it formed an inner limit of the peritubular matrix.

The first indication of the development of the peritubular matrix appeared as a heavy mineral deposition at the rim of the dentinal tubule. With advancing stages, a layer formed of irregularly arranged crystals developed there. During the widening of this layer at the expense of the dentinal tubules, mineralization increased inward from the region of junction with the intertubular matrix until the layer attained a homogeneously dense mineralization. During the appositional growth of the dentin, an acute narrowing of the predentinal tubules occurred at the dentino-predentinal junction because of the active formation of the peritubular matrix. The forming activity of the peritubular matrix, however, seemed to decrease rapidly and to cease during a later stage of dentinogenesis.

The developmental procedure of the peritubular matrix seemed to be different in some respects from the occlusive procedure of the dentinal tubules seen in the sclerosed root dentin. Unlike the development of the peritubular matrix, which grows in an appositional fashion and maintains a clear forming front, the occlusion of the tubules occurred rather diffusely in the dentinal tubules.

This article has been cited by other articles:

				S. Habelitz, B.J. Rodriguez, S.J. Marshall, G.W. Marshall, S.V. Kalinin, and A. Gruverman Peritubular Dentin Lacks Piezoelectricity J. Dent. Res., September 1, 2007; 86(9): 908 - 911. [Abstract] [Full Text] [PDF]