Water Fluoridation

Community water fluoridation (CWF) is the process of adjusting the amount of fluoride in drinking water to prevent cavities (tooth decay).^{[1, 2]} Cavities are caused by acid-producing bacteria that remove minerals from the surface of a tooth, resulting in tooth decay.^[3] Fluoride provides a protective barrier against harmful bacteria, which prevents cavities by keeping the tooth enamel strong.^[3] While fluoride occurs naturally in water, the concentration is usually not sufficient to prevent cavities.^[4] Community water fluoridation reaches everyone in the community regardless of age, education, income level, or access to routine dental care.

Cavities are one of the most common chronic diseases in children and adolescents.^{[5, 6]} More than half of children aged 6 to 8 have had a cavity in at least one of their baby (primary) teeth^[6] Among adults aged 20–64, 9 in 10 have experienced cavities and 1 in 4 have untreated tooth decay.^[6] CWF was a major contributor to the dramatic decline of tooth decay in the U.S. in the 1900s.^[3] Because of its contribution to the dramatic decline in cavities since the 1960s, CDC declared community water fluoridation one of ten great public health achievements of the twentieth century.^[7] However, about 77 million Americans served by community water systems still do not have access to water with sufficient levels of fluoride to prevent tooth decay.^[8] As part of Healthy People 2030, the U.S. has set a goal for 77.1 percent of Americans served by community water systems to have access to optimal fluoridation by 2030.^[9]

A systematic review of water fluoridation literature found that the prevalence of cavities was substantially lower in communities with CWF and that the prevalence of new cavities increased when CWF was discontinued.^[4] A combined evidence review (systematic reviews and additional studies) showed a 15 percent decrease in cavities following initiation of CWF, with the prevalence of cavities reduced across all socioeconomic groups.^[10] Additionally, there is no evidence that community water fluoridation results in severe dental or medical adverse effects.^[4]

An economic review of multiple studies found that benefits ranged from $1.10 to $135 of benefit for every $1 invested.^[11] Per capita annual costs for CWF ranged from $0.11 to $24.38, while benefits ranged from $5.49 to $93.19. ^[11] Benefit to cost ratios increase as the size of the community increases.^[11] A recent 2016 economic analysis found that for communities of 1,000 or more people, the savings associated with water fluoridation exceeded estimated program costs, with an average annual savings of $20 per dollar invested. ^[12] Additionally, individuals in communities that fluoridate water save an average of $32 per person by avoiding treatment for cavities.^[12] Nationwide, this same study found, community water fluoridation programs have been estimated to provide nearly $6.5 billion dollars a year in net cost savings by averting direct dental treatment costs (tooth restorations and extractions) and indirect costs (losses of productivity and follow-up treatment.)^[12]