Dentistry => Fluoridation
Fluoridation, addition of fluoride to public water supplies to reduce tooth decay. Fluoride in the teeth and saliva increases the ability of teeth to replace minerals immediately when decay-producing acids attack the teeth. Fluoride is a compound consisting of the element fluorine and a metallic element such as sodium (forming sodium fluoride, used in water supplies) or tin (forming stannous fluoride, used in toothpaste). More than half of the United States population now drinks fluoridated water from municipal water supplies.
Water fluoridation has been recognized as a significant method in preventing tooth decay since the 1930s. Numerous studies in the United States, Canada, and Britain over the past 60 years have shown that children with fluoridated water supplies experience 50 to 70 percent less tooth decay than others with nonfluoridated water by the time they become teenagers.
The maximum protection by fluoridation against tooth decay occurs when children consume fluoridated water from birth through age 13, the years of tooth development. However, continued fluoride treatment for teeth beyond the teenage years carries significant benefits. For example, exposed root surfaces along the gums in adults are also protected by fluorides.
In areas where water fluoridation is not practical or desirable, fluoride supplements in the diet during the ages of tooth formation can provide protection. Some countries make fluoridated salt available. Other countries depend only on the topical application of fluoride by a dentist or dental hygienist, or on mouthwashes containing fluorides. However, water fluoridation remains the cheapest, most effective form of fluoride treatment.
The study of fluoridation began in 1916 when Frederick S. McKay, a Colorado dentist, observed that mottled, or stained, tooth enamel was caused by a substance in some supplies of drinking water. McKay noted that teeth with mottled enamel had a greater resistance to decay. In 1931 the unknown substance was identified as fluoride.
Studies conducted from 1933 to 1942 showed that children experienced up to 70 percent less tooth decay in communities with water supplies containing naturally occurring fluorides at levels of at least 1 part fluoride to 1 part per million (ppm) of water, compared with children in communities with little or no naturally fluoridated water. Subsequent research based on population studies by the United States Public Health Service established 1 ppm of fluoride as the optimal concentration in water. Fluorosis (tooth staining) was found to occur at levels above 1.5 or 2.0 ppm, while only 10 percent of the children studied showed minimal changes in tooth coloring enamel at 1 ppm.
As a result of these early studies, in 1945 Grand Rapids, Michigan, became the first community in the world to add a fluoride compound to the municipal drinking water supply.
Since 1950 the American Dental Association, American Medical Association, U.S. Public Health Service, National Institutes of Health, and World Health Organization have endorsed water fluoridation at recommended levels. Yet, despite overwhelming evidence of the value and safety of fluorides used at recommended levels, water fluoridation is still opposed by some people. Reasons for opposition include concerns about possible long-term harmful effects such as a higher risk of osteoporosis; objections to what is perceived as mass medication that curtails freedom of choice; and in some instances, a violation of religious beliefs against the use of medicines.