Fluoride is a mineral that occurs naturally in many water sources, with average concentrations ranging from 0.1 to 10 ppm, according to Virginia's Community Colleges. Since 1945, municipal agencies in the U.S. have added sodium fluoride to public water in an attempt to improve oral health. While the American Dental Association and other health agencies endorse fluoridation, fluoride levels must be monitored carefully to avoid potential negative health effects associated with high concentrations.
Improved Dental Health
According to the American Dental Association, adding sodium fluoride to water supplies helps to prevent and reverse tooth decay by 20 to 40 percent. Fluoride strengthens enamel and helps to prevent tooth root decay in people of all ages, but it provides the most significant benefits for children.
Reduced Dental Expenses
Virginia's Community Colleges estimate that for every $1 spent adding sodium fluoride to the water, people in the U.S. reduce dental expenses by $50. The Centers for Disease Control and Prevention report on research in Scotland, which found that fluoridation results in a 49 to 54 percent reduction in dental expenses for young children. Given that roughly half of dental expenses are paid for out of pocket, according to the CDC, reduced dental spending represents a benefit to both individuals and society as a whole.
Potential for Fluorosis
The average municipality aims to keep sodium fluoride levels at 1 ppm or below according to Virginia's Community Colleges. At levels of 2 to 13 ppm, a condition known as fluorosis may occur. Fluorosis is characterized by brown stains and mottling on the surface of the teeth. This condition is largely an aesthetic issue and does not impact dental health, but it cannot be reversed without cosmetic treatment.
Risk of Skeletal Issues
The consumption of high levels of fluoride can lead to a condition known as skeletal fluorosis. Excess fluoride can build up in and around the bones of the body, contributing to pain, stiffness and even calcification, which can impact mobility. Skeletal fluorosis is primarily a problem in areas with naturally high levels of fluoride, such as India, the Middle East and Asia. To avoid skeletal fluorisis in the U.S., municipal agents must test water carefully to avoid adding excess sodium fluoride to areas that have naturally high fluoride levels.
Some critics of fluoridation believe that the addition of sodium fluoride to water contributes to or exacerbates existing thyroid conditions. Though evidence supporting this theory is limited, a 2005 study by the International Society for Fluoride Research found that sodium fluoride restricts thyroid activity in laboratory animals.