Dental Caries (Cavities): Community Water Fluoridation

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Findings and Recommendations

The Community Preventive Services Task Force (CPSTF) recommends community water fluoridation to reduce tooth decay (i.e., dental caries or cavities).

The full CPSTF Finding and Rationale Statement and supporting documents for Dental Caries (Cavities): Community Water Fluoridation are available in The Community Guide Collection on CDC Stacks.

Intervention

Community water fluoridation is the controlled adjustment of fluoride in a public water supply to help prevent tooth decay in the community. Fluoride prevents tooth decay by preventing demineralization and enhancing remineralization of tooth enamel. Although fluoride occurs naturally in water across the U.S., it is usually lower than the optimal concentration needed to prevent dental caries.

About The Systematic Review

The CPSTF finding is based on evidence from a systematic review published in 2000 (McDonagh et al., search period 1966-1999; 26 studies on caries; 13 on oral health disparities; 88 on fluorosis), combined with more recent evidence (search period 1999-2012; 29 studies). All included studies evaluated intervention effectiveness of community water fluoridation among children. The systematic review was conducted on behalf of the CPSTF by a team of specialists in systematic review methods, and in research, practice, and policy related to oral health.

Study Characteristics

  • Included studies were conducted in the United States, Europe, Canada, Asia, South America, Africa, Australia, the Middle East, and New Zealand
  • Fluoride concentrations in most of the intervention sites ranged from 0.7 to 1.2 mg/L

Summary of Results

Results from both the McDonough et al. review and the updated search for evidence showed a decrease in new dental caries after community water fluoridation began and an increase in new dental caries when it stopped.

  • Combined evidence showed a median decrease of 15.2 percentage points in caries after community water fluoridation began (12 studies)
  • Included studies showed that community water fluoridation reduced the prevalence of dental caries across socioeconomic groups

Summary of Economic Evidence

Ten studies were included in the economic review. Monetary values are presented in 2013 U.S. dollars.

Intervention cost:

  • For urban communities, per capita annual cost ranged from $0.11 to $4.92 (6 studies)
  • Population size was the main cause of variation; as the size of a community’s population went up, the cost per person went down

Intervention benefit:

  • Studies that provided benefit and cost information reported a per capita annual benefit of community water fluoridation that ranged from $5.49 to $93.19 (6 studies)

Benefit cost ratio:

  • Benefit cost ratios ranged from 1.1:1 to 135.0:1 (6 studies)
  • Lower benefit cost ratios generally were associated with small community population sizes, with ratios increasing as community population size increased

Applicability

Based on results, the Task Force finding should be applicable to the following:

  • Communities across the United States
  • Groups from all socioeconomic status (SES) groups

There is limited information about the unique effects of community water fluoridation among populations that are exposed to fluoride through other sources (e.g., dental products, infant formula).

Evidence Gaps

  • The contribution of alternative fluoride sources (e.g., toothpaste, mouth rinses), especially with growing concerns about the overall effect of multiple fluoride exposures
  • The effects of drinking bottled water on the benefits of community water fluoridation
  • The role of water hardness and dietary calcium in the bioavailability of fluoride in individuals and communities with varying milk consumption patterns and degrees of water hardness. The presence of calcium circulating in the body is believed to be associated with reduced fluoride absorption from the gastrointestinal tract.
  • Standardized measurement and reporting of dental fluorosis and caries to reduce measurement errors
  • Non-dental harms of community water fluoridation
  • The benefit of community water fluoridation to adults

Implementation Considerations and Resources

  • More than 70% of U.S. residents who rely on community water systems receive fluoridated water (CDC, 2013)
  • Potential barriers to implementation include start-up costs, social acceptability, media attention, and limited knowledge of the benefits and harms of community water fluoridation among the general public, healthcare providers, and policymakers
  • Messages that address these potential barriers and are tailored to the general public and healthcare professionals could lead to greater awareness and acceptance of community water fluoridation
  • Daily monitoring of fluoride levels in fluoridated community water supplies is recommended to maintain optimal fluoride concentrations (CDC, 1995)
  • There is no evidence that shows community water fluoridation results in severe dental fluorosis

Crosswalks

Healthy People 2030 icon Healthy People 2030 includes the following objectives related to this CPSTF recommendation.