Abnormal tooth tissue in human odontodysplasia.

The affected teeth in this case of odontodysplasia exhibited abnormal hypoplastic enamel, abnormal dentin containing extensive interglobular regions and completely lacking a peritubular matrix, and an abnormal irregular tissue consisting of highly calcified and partially fused granules located within the dentin of the tooth tips. Electron micrographs of the irregular tissue showed that the granules consisted of crystallites densely and radically packed in a noncollagenous amorphous matrix. Granules were surrounded by a slightly calcified, irregularly arranged, collagenous matrix. The irregular tissue formed in the pulp of the tooth tip befofe and independently of the dentin. It was at least partially formed by pulpal calcification. Abnormal dentin matrix was formed by odontoblasts which were less differentiated than normal. Odontodysplastic teeth showed abnormal differentiation of odontoblasts and ameloblasts resulting in defective enamel and dentin and, in extreme cases, in extensive pulpal calcification.