Etiology of Enamel Hypoplasia and Interglobular Dentin: The Roles of Hypocalcemia and Hypophosphatemia

Abstract

In the course of a long-term investigation of children with three well-defined disturbances of calcium and phosphate homeostasis - hereditary vitamin D dependency rickets, X-linked hypophosphatemia and hypoparathyroidism - we have observed distinctive distributions of enamel hypoplasia and interglobular dentin that provide a clue to the pathogenesis of these dental lesions. Each of the 25 patients with X-linked hypophosphatemia had extensive interglobular dentin in the primary and permanent teeth but no enamel hypoplasia; these patients were normocalcemic but very hypophosphatemic. Each of ten patients with vitamin D dependency rickets had severe enamel hypoplasia in the permanent teeth, and in the 7 patients whose teeth were examined histologically moderate interglobular dentin was observed in each; these patients were hypocalcemic and, because of secondary hyperparathyroidism, also hypophosphatemic. Fifteen of 21 children with hypo parathyroidism had severe enamel hypoplasia but none had interglobular dentin; these patients were hypocalcemic and hypopphosphatemic. From these observations we have formulated a unifying hypothesis that enamel hypoplasia, in disturbances of calcium and phosphate homeostasis; is caused by hypocalcemia and interglobular dentin is caused by hypophosphatemia.