enamel hypoplasia, a defect in which the enamel of the teeth is hard but thin and deficient in amount as a result of defective enamel matrix formation with a shortage of the cementing substance. It is characterized by lack of contact between teeth, rapid breakdown of occlusal surfaces, and a yellowish-brown stain that appears where the dentin is exposed. The condition affects both primary and secondary dentition. It is transmitted genetically or caused by environmental factors such as vitamin A, C, or D deficiency; fluorosis; rash-producing childhood diseases; congenital syphilis; injury or trauma to the mouth; or administration of tetracyclines during the second half of pregnancy or during early tooth development. Compare enamel hypocalcification. See also amelogenesis imperfecta.
