There are two ways that you can benefit from fluoride: topically and systemically.
Topical fluoride is the type of fluoride you receive at the dental office or when you use dental products—such as toothpastes or mouth rinses. Systemic fluoride is ingested, usually through a public water supply, which in the United States applies to nearly 74 percent of the population. While teeth are forming under the gums, the fluoride taken in largely from drinking water and other beverages strengthens tooth enamel making it stronger and more resistant to cavities. This provides what is called a “systemic” benefit. After teeth erupt, fluoride helps rebuild (remineralize) weakened tooth enamel and reverse early signs of tooth decay. When you brush your teeth with fluoride toothpaste, or use other fluoride dental products, you are providing a “topical” benefit because the fluoride is applied to the surface of your teeth.
In addition, drinking fluoridated water and other fluoridated beverages continues to provide a topical benefit because it becomes part of your saliva, constantly bathing the teeth and helping to rebuild weakened tooth enamel. The maximum reduction in tooth decay occurs when fluoride is available systemically and topically. Studies show that community water fluoridation, the addition of fluoride to water to a recommended level for preventing tooth decay, prevents at least 25 percent of tooth decay in children and adults. In fact, community water fluoridation is noted as the single most effective public health measure to prevent tooth decay and the Centers for Disease Control and Prevention has proclaimed community water fluoridation as “one of 10 great public health achievements.” The American Dental Association and more than 100 other national and international organizations recognize the public health benefits of fluoridated water in preventing tooth decay.