THE COURSE OF THE ENAMEL PRISMS NEAR THE CEMENTO-ENAMEL JUNCTION

¹ Division of Dental Research, University of Rochester School of Medicine and Dentistry, Rochester, N. Y., and the Department of Dental Research, Baylor University College of Dentistry, Dallas, Tex.

The enamel prisms in the region of the cemento-enamel junction, as seen in sections of enamel in the stage of prism differentiation, usually occupy an occlusoangular relationship with the dentin. This finding was not confirmed in an investigation of ground sections of fully calcified enamel wherein the number of specimens revealing an occluso-angular relationship between rods and dentin did not exceed 30% of the total. The discrepancy appeared to be the result of a change in the course of the prisms from an occluso-angular to one at right angles to the long axis of the tooth, evidently occurring during the stage of enamel maturation. Occasionally, the enamel rods near the cemento-enamel junction may lie in an arc, the peripheral end of which is directed toward the root apex. Prisms directed apically and occluso-angularly may occur at various places along the cemento-enamel junction of the same tooth.