Water fluoridation for the prevention of dental caries

Summary of methods

Types of studies. We included cost-effectiveness study designs evaluating community water fluoridation programmes. We did not limit by date of publication.

Search methods. We conducted searches of the following databases.

• MEDLINE Ovid (1946 to 19 February 2024).
• Embase Ovid (1980 to 19 February 2024).
• NHS Economic Evaluation Database (EED) (inception to 31 March 2015); although we ran the search on 19 February 2024, bibliographic records were published on NHS EED until 31 March 2015 and the database was no longer updated after this date.

For MEDLINE and Embase, we used the same terms for water fluoridation that were used in the main database searches in the Cochrane Review; these terms are included in the Appendix of published Cochrane Review. We combined these (using AND) with a search filter for economic studies developed by the Scottish Intercollegiate Guideline Network (accessed on 19 February 2024). For NHS EED, we used the following strategy ('Any fields'): (water fluorid* OR water fluoridation) OR (fluorid* AND water* AND (caries OR carious OR dental OR tooth OR teeth OR plaque)).

We also included unpublished economic evaluations that we were aware of from colleagues in the field; we did not use a systematic approach to search for unpublished reports.

Results

Results of search. We found 565 reports from database searches. After removal of duplicates, we searched the titles and abstracts of 437 reports. We excluded 381 reports, and sourced the full text of 56 reports. Of these, 23 reports were of interest and we excluded the remaining reports. We also included two reports of economic evaluations of the LOTUS study and CATFISH study which were not published at the time of the search. In total, we considered 25 reports of 24 studies when preparing a brief economic commentary for this topic.

Brief economic commentary. Most economic evaluations were conducted in the USA, UK, and Australia or New Zealand; reports generally included a perspective of costs from a healthcare payer or water fluoridation provider. Most studies reported the results of cost-effectiveness analyses (e.g. cost per case of caries averted or cost per unit decayed, missing or filled teeth (dmft in primary dentition; DMFT in permanent dentition) reduction) or return on investment, reporting net savings from water fluoridation due to caries averted. There were comparatively few examples of cost-utility analyses (e.g. cost per quality adjusted life year gained), and this may be due to concerns about a lack of sensitivity of generic quality of life measures to capture the full range of oral health outcomes that are valued by the general public.
 
Most studies were based on calculations or lifetable modelling approaches that use data from multiple sources, including existing literature, cross-sectional data and expert opinion. Economic modelling assumptions were not always clearly reported (e.g. model type, key assumptions, lists of parameter inputs, etc.), which made it difficult to judge the extent to which all relevant costs and benefits were included. For older studies, this is likely due to publication prior to the release of current reporting standards for economic evaluation.

Most studies provided comprehensive estimates of the costs of delivering water fluoridation, with clearly defined assumptions. However, studies often lacked detail on the source of effectiveness data or an assessment of the generalisability of the effectiveness data source to the underlying modelled population. It would appear that the magnitude of benefit of water fluoridation has reduced over time, perhaps due to populations with greater exposure to other fluoride sources, and this was not always accounted for in economic models. This may over-state the magnitude of cost-savings achieved. Conversely, many studies did not fully capture the total, life-time horizon costs associated with caries prevention. Few studies captured productivity losses associated with dental decay. These issues may have led to underestimation of cost savings in some studies.

In general, across the studies, some clear findings emerge. Community water fluoridation appears to offer good value for money due to its low per capita intervention delivery costs, potential to reduce caries, even at low magnitudes of effect size, and the related impact on dental treatment costs averted. However, the magnitude of cost-effectiveness (or net cost-savings) is shown to be sensitive to the size of the fluoridated population, the magnitude of water fluoridation's effectiveness observed in more recent studies, and the underlying caries risk in the treated population. Therefore, whilst in general water fluoridation appears to offer good value for money, this is context dependent and each proposed scheme introduction should be considered on a case by case basis according to population size, magnitude of benefit and underlying caries prevalence in the population served.
 

References to studies included in this brief economic commentary

Atkins CY, Thomas TK, Lenaker D, Day GM, Hennessy TW, Meltzer MI. Cost-effectiveness of preventing dental caries and full mouth dental reconstructions among Alaska Native children in the Yukon-Kuskokwim delta region of Alaska. Journal of Public Health Dentistry 2016;76(3):228-40.

Attwood D, Blinkhorn AS. Reassessment of the effect of fluoridation on cost of dental treatment among Scottish schoolchildren. Community Dentistry & Oral Health Epidemiology 1989;17(2):79-82.

Birch S. The relative cost effectiveness of water fluoridation across communities: analysis of variations according to underlying caries levels. Community Dental Health 1990;7(1):3-10.

Ciketic S, Hayatbakhsh MR, Doran CM. Drinking water fluoridation in South East Queensland: a cost-effectiveness evaluation. Health Promotion Journal of Australia 2020;21(1):51-6.

Cobiac LJ, Vos T. Cost-effectiveness of extending the coverage of water supply fluoridation for the prevention of dental caries in Australia. Community Dentistry and Oral Epidemiology 2012; 40(4):369-76.

Cronin J, Moore S, Harding M, Whelton H, Woods N. A cost-effectiveness analysis of community water fluoridation for schoolchildren. BMC Oral Health 2021;21(1):158.

Doessel DP. Cost-benefit analysis of water fluoridation in Townsville, Australia. Community Dentistry and Oral Epidemiology 1985;13(1):19-22.

Edelstein BL, Hirsch G, Frosh M, Kumar J. Reducing early childhood caries in a Medicaid population: a systems model analysis. Journal of the American Dental Association (1939) 2015;146(4):224-32.

Fyfe C, Borman B, Scott G, Birks S. A cost effectiveness analysis of community water fluoridation in New Zealand. New Zealand Medical Journal 2015:128(1427):38-46.

Goodwin M, Emsley R, Kelly MP, Sutton M, Tickle M, Walsh T, et al. Evaluation of water fluoridation scheme in Cumbria: the CATFISH prospective longitudinal cohort study. Public Health Research 2022;10(11).

Griffin SO, Jones K, Tomar SL. An economic evaluation of community water fluoridation. Journal of Public Health Dentistry 2001;61(2):78-86.

Horowitz HS, Heifetz SB. Methods of assessing the cost-effectiveness of caries preventive agents and procedures. International Dental Journal 1979;29(2):106-117.

Kroon J, Van Wyk PJ. A model to determine the economic viability of water fluoridation. Journal of Public Health Dentistry 2012;72(4):327-33.

Manau C, Cuenca E, Martinez-Carretero J, Salleras L. Economic evaluation of community programs for the prevention of dental caries in Catalonia, Spain 1987:15(6):297-300.

Marino R, Fajardo J, Morgan M. Cost-effectiveness models for dental caries prevention programmes among Chilean school children. Community Dental Health 2012;29(4):302-8.

Moore D, Nyakutsikwa B, Allen T, Lam E, Birch S, Tickle M, et al. How effective and cost-effective is water fluoridation for adults and adolescents? The LOTUS 10-year retrospective cohort study. Community Dentistry & Oral Epidemiology 2024; doi: 10.1111/cdoe.12930 (online ahead of print)

Nelson W, Swint JM. Cost-benefit analysis of fluoridation in Houston, Texas. Journal of Public Health Dentistry 1976;36(2):88-95.

Niessen LC, Douglass CW. Theoretical considerations in applying benefit-cost and cost-effectiveness analyses to preventive dental programs. Journal of Public Health Dentistry 1984;44(4):156-68.

O'Connell JM, Brunson D, Anselmo T, Sullivan PW. Costs and savings associated with community water fluoridation programs in Colorado. Preventing Chronic Disease 2005;2 Spec no:A06.

O'Connell J, Rockell J, Ouellet J, Tomar SL, Maas W. Costs and savings associated with community water fluoridation in The United States. Health Affairs 2016;35(12):2224-32.

O'Keefe JP. A case study on the cost effectiveness of water fluoridation. Would fluoridation make economic sense in Montreal today? Ontario Dentist 1994;71(8):33-8.

Tchouaket E, Brousselle A, Fansi A, Dionne PA, Bertrand E, Fortin C. The economic value of Quebec's water fluoridation program. Journal of Public Health (Germany) 2013;21(6):523-33.

Whittaker W, Goodwin M, Bashir S, Sutton M, Emsley R, Kelly MP, et al. Economic evaluation of a water fluoridation scheme in Cumbria, UK. Community Dentistry & Oral Epidemiology 2024; doi:10.1111/cdoe.12958 (online ahead of print).

Wright JC, Bates MN, Cutress T, Lee M. The cost-effectiveness of fluoridating water supplies in New Zealand. Australian and New Zealand Journal of Public Health 2001;25(2):170-8.

Zhao Y, Raymond K, Chondur R, Sharp W, Gadd E, Baillie R, et al. Costs and benefits of community water fluoridation in remote Aboriginal communities of the Northern Territory 2023;31(5):1017-26.