Congenital hyperbilirubinemia causes a yellowish tooth discoloration. Defects in tooth enamel may be caused by the abnormal calcium metabolism associated with rickets, which results in enamel hypoplasia. A rough, irregular band forms in the enamel when abnormal calcification occurs. Any prolonged febrile illness during odontogenesis can produce a permanent narrow zone of chalky, pitted enamel, visible after the tooth erupts. Thus, the age at which the disease occurred and its duration can be estimated from the location and height of the band.
Amelogenesis imperfecta, an autosomal dominant disease, causes severe enamel hypoplasia.
Chronic snorting of cocaine can result in widespread decalcification of teeth, because in saliva, the drug dissociates into a base and hydrochloride, often abetted when the user massages the oral mucosa to hasten drug absorption. Treatment of all these conditions consists of extensive restorative dentistry, particularly artificial crowns, after the cause is removed or corrected. Swimmers who spend much time in overchlorinated pools lose considerable amounts of enamel. The likelihood of fluorosis increases with concentration of fluoride and amount of fluoridated water ingested . Enamel changes range from irregular whitish opaque areas to severe brown discoloration of the entire crown with a roughened surface.