The Probert Encyclopaedia of Medicine

DENTINE

Dentine (dentin) is the main substance of the tooth, composing the bulk of the crown and root of the tooth.
Dentine is similar in hardness to compact bone tissue, found throughout the skeleton, and features about 30% organic tissue. Like the enamel, no cells or vessels penetrate the
dentine, so that damage to the dentine (as in the case of a dental cavity) cannot be repaired. In some teeth, a secondary dentine may form as an accretive patch over damaged or occluded tooth tissue, however. Though no cells or vessels penetrate the dentine, small tubules do penetrate into the dentine matrix from the pulp cavity. Within these tubules are housed odontoblasts in a protoplasmic base. These tubules make the dentinal matrix sensitive to contact or temperature changes.
Research Dentine