Tooth decay, known formally as dental caries, has been a serious health problem for all nations since time immemorial. For centuries, tooth decay was thought to be the handiwork of an elusive and, in some cultures, evil tooth worm that gnawed holes into the white, highly mineralized enamel and left all those in its wake in pain. But superstition has yielded to science and its explanation that certain oral bacteria discharge mineral-eroding acid onto the enamel, starting the gradual process of decay. Over the last several decades, dental researchers have made tremendous progress in defining and learning to thwart the decay process. This work has involved the three-pronged strategy of discovery, innovation, and prevention - and produced one of the major public health success stories of the 20th century.
Few people were spared the ordeal of losing teeth, often early in life. The combination of tooth decay and periodontal diseases left 17 million people age 45 and older — about three out of 10 Americans — with none of their natural teeth. In fact, the most common cause of WWII draft rejection was too few teeth because of tooth decay. Until the 1970s, the cause of tooth decay continued to be a subject of debate, with some believing dietary deficiencies were the culprit and others focusing on oral bacteria. This uncertainty made effective prevention strategies difficult, if not impossible, to create. Moreover, brushing one's teeth each day was a fairly recent hygienic step forward in dental care, reportedly popularized by returning soldiers from World War II.
The NIH completed the first water fluoridation study that established the benefits of fluoride in fighting tooth decay. Several years would pass before fluoride, the mainstay of modern prevention strategies, would become a common ingredient in water, toothpaste, and other products.