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Preventing Dental Caries: Community Water Fluoridation

Task Force Finding

The Community Preventive Services Task Force  recommends community water fluoridation based on strong evidence of effectiveness in reducing dental caries (tooth decay) across populations. Evidence shows the prevalence of caries is substantially lower in communities with community water fluoridation. In addition, there is no evidence that community water fluoridation results in severe dental fluorosis.

Read the full Task Force Finding and Rationale Statement for details including implementation issues, possible added benefits, potential harms, and evidence gaps.

Intervention Definition

Community water fluoridation is the controlled adjustment of fluoride in a public water supply to optimal concentration External Web Site Icon to prevent caries (tooth decay) among members of the community. Fluoride acts to impede demineralization and to enhance the remineralization of dental enamel, both of which prevent dental caries. While 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 Task Force finding is based on evidence from a systematic review published in 2000 (McDonough 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; 2 on caries; 3 on oral health disparities; 29 on fluorosis). The systematic review was conducted on behalf of the Task Force by a team of specialists in systematic review methods, and in research, practice, and policy related to oral health. The finding updates and replaces the 2000 Task Force finding on community water fluoridation

Results

Results from both the McDonough et al. review and the updated search for evidence show a decrease in new dental caries following fluoride initiation and an increase in new dental caries experience following its discontinuation.

  • Combined evidence shows a median decrease of 15.2 percentage points in caries experience following fluoride initiation (12 studies).
  • Included studies show that community water fluoridation reduces the prevalence of dental caries across socioeconomic (SES) groups.
2000 Review -- McDonough et al. (search period 1966-1999)
  • Effects following initiation of community water fluoridation:
    • Individuals free of dental caries: median increase of 14.6 percentage points (Interquartile Interval [IQI]: 5.1 to 22.1 percentage points; 11 studies).
    • Decayed, missing, or filled teeth: median decrease of 2.25 fewer (IQI 1.28 to 3.63 teeth; 10 studies).
  • Effects following discontinuation of community water fluoridation:
    • Studies reported an increase in the number of decayed, missing, or filled teeth (6 studies) or surfaces (2 studies).
Updated Evidence (search period 1999-2012)
  • Following initiation of community water fluoridation:
    • Individuals free of dental caries: median increase of 25.1 percentage points (IQI: 20.4 to 30.5 percentage points; 1 study).
  • When community water fluoridation was discontinued:
    • The total number of decayed, missing, or filled tooth surfaces decreased by 0.59 among children 8 years of age, and 1.39 among children 14 years of age (1 study) when compared to communities that continued community water fluoridation.
    • The number of new decayed, missing, or filled surfaces increased by 0.13 among children 8 years of age, and by 0.47 among children 14 years of age (1 study) when compared to communities that continued community water fluoridation.

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.

Applicability

  • Results are considered applicable to the United States.
  • Available data suggest community water fluoridation is effective across all 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).

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.
  • Cost estimates were based two main components: one-time fixed cost (for equipment, pipework, fluoridation pump, and tank area) and annual recurring cost (for fluoride compounds, monitoring, maintenance, and operations).

Intervention benefit:

  • Benefit-only studies that used regression models concluded that the presence of water fluoridation was related to a reduction in dental treatment cost or claims (4 studies).
  • Studies that provided benefit and cost information reported a per capita annual benefit of CWF that ranged from $5.49 to $93.19 (5 studies).
  • The main causes of variation were the number of benefit components considered in each study (e.g., averted health care cost, averted productivity loss, other losses averted) and the assumptions made. Geographical differences in dental treatment and labor costs also played a role.

Benefit-cost ratio:

  • Benefit-cost ratios ranged from 1.1:1 to 135:1 (6 studies).
  • Lower benefit–cost ratios generally were associated with small community population sizes, with ratios increasing with community population size. This is mainly related to the economies of scale on the cost side.

Considerations for Implementation

The following considerations are drawn from studies included in the evidence review, the broader literature, and expert opinion. The Community Guide does not conduct systematic reviews of implementation considerations.

  • Over 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. Where community water fluoridation is in place, daily monitoring is recommended to ensure optimal fluoride concentrations are maintained (CDC, 1995).

Supporting Materials

Publication Status

Full peer-reviewed articles of this systematic review will be posted on the Community Guide website when published. Subscribe External Web Site Icon to be notified when we post these publications or other materials. See our library for previous Community Guide publications on this and other topics.

References

Centers for Disease Control and Prevention. 2010 Water Fluoridation Statistics. Retrieved from http://www.cdc.gov/fluoridation/statistics/2010stats.htm External Web Site Icon. Accessed August 2, 2013.

Centers for Disease Control and Prevention. Engineering and administrative recommendations for water fluoridation, 1995. MMWR 1995;44(RR-13):1-40.




Disclaimer

The findings and conclusions on this page are those of the Community Preventive Services Task Force and do not necessarily represent those of CDC. Task Force evidence-based recommendations are not mandates for compliance or spending. Instead, they provide information and options for decision makers and stakeholders to consider when determining which programs, services, and policies best meet the needs, preferences, available resources, and constraints of their constituents.

Sample Citation

The content of publications of the Guide to Community Preventive Services is in the public domain. Citation as to source, however, is appreciated. Sample citation: Guide to Community Preventive Services. Preventing dental caries: community water fluoridation. www.thecommunityguide.org/oral/fluoridation.html. Last updated: MM/DD/YYYY.

Review completed: April 2013