This year, the United States marks the 70th anniversary of community water fluoridation, one of public health’s greatest success stories.
Almost all water contains some naturally-occurring fluoride, but usually at levels too low to prevent tooth decay. Water fluoridation is the process of adding a small amount of fluoride to public water supplies to a level known to make teeth stronger and prevent cavities. In 1945, Grand Rapids, Michigan, was the first city in the U.S. to fluoridate its water, and by the early 1950’s, results were clear: Compared to school children from nearby areas that did not fluoridate their water, children in Grand Rapids had fewer cavities.
Since then, water fluoridation has been a major factor resulting in lower rates of tooth decay in the United States, with each generation enjoying better oral health than the previous one. As of 2012, more than 210 million people, or 3 in 4 Americans who use public water supplies, drank water with enough fluoride to prevent tooth decay.
Effective and Safe
Fluoridated water is effective, because it keeps a low level of fluoride in the mouth, specifically in the dental plaque and saliva, all day. Even with the use of other fluoride products, such as toothpaste and mouth rinses, fluoridated water reduces tooth decay by 25% among children and adults. In communities with water fluoridation, school children have, on average, about 2 fewer decayed teeth compared to children who don’t live in fluoridated communities.
That’s important because oral health affects every aspect of our lives—diet, sleep, mental health, social connections, school, and work. Untreated tooth decay can cause pain, school absences, difficulty concentrating, and poor appearance—all contributing to reduced quality of life and ability to succeed.
Fluoridation has been identified as the most feasible and cost-effective method of delivering fluoride to all members of the community, regardless of age, education, or income. These advantages combined with fluoridation’s contribution to dramatic declines in both the prevalence and severity of tooth decay led the Centers for Disease Control and Prevention (CDC) to name water fluoridation as one of ten great public health achievements of the 20th century.
Scientists in the United States and other countries have studied the safety and benefits of fluoridated water for decades, and found no convincing evidence to link water fluoridation and any potential unwanted health effect other than dental fluorosis.
Dental fluorosis is a change in the appearance of tooth enamel. It can occur when young children (less than 8 years of age) regularly take in fluoride when their permanent teeth are still developing.
Today there are more sources of fluoride, such as toothpaste and mouth rinse, than when fluoridation was first introduced. With greater availability of fluoride, there has been an increase in the dental fluorosis. Most dental fluorosis in the U.S.—more than 90 percent—appears in its milder forms as white spots on the tooth surface that may not be noticed.
To balance the benefits of fluoridation with the chance for dental fluorosis, the US Public Health Service just published an updated recommendation for the optimal level of fluoride in drinking water to prevent tooth decay[403 KB]. The new recommendation sets the level of fluoride in drinking water at 0.7 mg/liter. This new guidance updates and replaces the previous recommended range of 0.7 mg/L to 1.2 mg/L. It is important to note that there is no federal “requirement” to fluoridate. States and local communities decide whether to fluoridate or not. CDC’s Division of Oral Health does provide technical help and training for state fluoridation programs.