The Science and Ethics of Water Fluoridation
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Source: Journal of the Canadian Dental Association
The Science and Ethics of Water Fluoridation
• Howard Cohen, BA, MA, PhD •
• David Locker, BDS, PhD •
© J Can Dent Assoc 2001; 67(10):578-80
A statement concerning the ethics of water fluoridation was published in a recent issue of the Journal of the Canadian Dental
Association.1 The arguments presented in that paper did not constitute what we would consider a complete and systematic
account of the scientific and moral issues involved. It is our contention that water fluoridation, by the very nature of the way it is
administered, engenders a number of moral dilemmas that do not admit to any easy solution. In this paper, we attempt to
elucidate the particular problems posed by this public health initiative, according to the principles of bioethics.
The Role of Bioethics
Whether or not water fluoridation reduces dental caries in child populations has been subject to considerable debate.2,3 This
debate is scientific rather than moral in character and revolves around the validity of the evidence concerning the benefits of
adding fluoride to community water supplies. However, even if it were universally accepted that water fluoridation is beneficial
and the scientific evidence incontrovertible, it would still have a moral dimension. This moral status arises in the application of
water fluoridation in health care policy and public health practice. Attitudes toward public health initiatives are of necessity
shaped by values. Bioethics is the study of the moral, social and political problems that arise from biology and the life sciences,
and that involve human well-being.4 Of particular relevance are the core values of autonomy, beneficence and truthfulness.
Beneficence and Autonomy
Beneficence denotes the practice of good deeds and signifies an obligation to benefit others or seek their good. How this
principle is put into practice depends on whose notion of good is applied. Health policy-makers and professionals, in
advocating for the addition of fluoride to drinking water, are making moral decisions about the well-being of individuals and
applying their own notions of good. If beneficent acts are to benefit the recipients of the actions, the basis for the goodness of
the actions must lie in the values or preferences of autonomous, self-determining individuals. In practice, however, beneficent
acts such as water fluoridation tend to be in conflict with autonomy. Since it is effectively impossible for individuals to opt out,
fluoridation takes away the freedom to choose.
Advocates of water fluoridation argue that the benefits accruing to society through reductions in dental caries outweigh any
harm to individual autonomy. Defenders of autonomy argue that fluoride is available from many sources, and so its benefits can
be realized without violating the principle of autonomy. However, this presumes that everyone in society can access these
alternative sources. The most vulnerable in society, it is countered, would surely miss out on the benefits of fluoride.1
Therefore, considering the benefit that accrues to disadvantaged groups in society, advocates of fluoridation contend that water
supplies should be fluoridated on the grounds that everyone, regardless of socioeconomic status, can benefit. The claim here is
that water fluoridation promotes social equity. This solution still leaves the conflict of beneficence and autonomy unresolved. In
fact, there appears to be no escape from this conflict of values, which would exist even if water fluoridation involved benefits
and no risks. However, water fluoridation does involve risks, in the form of increases in the prevalence and severity of dental
fluorosis. Moreover, as Coggon and Cooper5 indicate, those most likely to benefit from water fluoridation are not necessarily
those placed at most risk. This complicates considerably any attempt to balance beneficence and autonomy.
Advocates of water fluoridation, in seeking to strike a balance between competing values, are attempting to reconcile
irreconcilables: the demands of moral autonomy cannot be made compatible with what could be regarded as the involuntary
medication of populations. This situation gives rise to the question of which values concerning the conflict between beneficence
and autonomy should inform decision making with respect to water fluoridation: those of health professionals or those of the
An assessment of the ethics of water fluoridation must also take into account the moral issues surrounding scientific inquiry in
order for health professionals to be justified in advising or compelling others how to act. This aspect pertains to the principle of
truthfulness, whereby health professionals are obligated to tell their patients the truth,6 for one cannot influence the way others
act without first being justified in one’s own beliefs.
The conventional view is that policy-makers are presented with a clear moral choice when weighing the benefits and harms
associated with water fluoridation. Historically this may have been the case. The original community trials of water fluoridation
indicated a substantial effect.7,8 However, over the past 25 years there has been a marked reduction in rates of dental caries
among children, such that the benefits of water fluoridation are no longer so clear. Although current studies indicate that water
fluoridation continues to be beneficial, recent reviews have shown that the quality of the evidence provided by these studies is
poor.9-11 In addition, studies that are more methodologically sound indicate that differences in rates of dental decay between
optimally fluoridated and nonfluoridated child populations are small in absolute terms.12,13 Canadian studies of fluoridated and
nonfluoridated communities provide little systematic evidence regarding the benefits to children of water fluoridation.14-17
Moreover, studies of the benefits to adults are largely absent,9 and there is little evidence that water fluoridation has reduced
social inequalities in dental health.10
Truthfulness entails a proper appraisal of the benefits and risks. Currently, the benefits of water fluoridation are exaggerated by
the use of misleading measures of effect such as percent reductions. The risks are minimized by the characterization of dental
fluorosis as a “cosmetic” problem. Yet a study of the psychosocial impact of fluorosis found that “10 to 17 year olds were able
to recognize very mild and mild fluorosis and register changes in satisfaction with the colour and appearance of the teeth.”18 The
investigators also stated, “The most dramatic finding was that the strength of association of [fluorosis] score with
psycho-behavioural impact was similar to that of overcrowding and overbite, both considered key occlusal traits driving the
demand for orthodontic care.” In the absence of a full account of benefits and risks, communities cannot make a properly
informed decision whether or not to fluoridate, and if so at what level, on the basis of their own values regarding the balance of
benefits and risks.
In the absence of comprehensive, high-quality evidence with respect to the benefits and risks of water fluoridation, the moral
status of advocacy for this practice is, at best, indeterminate, and could perhaps be considered immoral.
These scientific and moral issues must be addressed and resolved if policy and practice with respect to water fluoridation are to
be considered ethically sound. Yet it is not clear that this work can be accomplished satisfactorily. The conventional view that
the ethical dilemmas posed by water fluoridation can be resolved by balancing the benefits and harms actually begs the
question, for it presumes that such a balance can be achieved. The preceding arguments indicate that this view needs to be
replaced by a moral account showing an appreciation for the ineradicability of the conflict of values that water fluoridation
engenders. They also raise the question of whose values should take precedence when decisions regarding water fluoridation
are being made.
Ethically, it cannot be argued that past benefits, by themselves, justify continuing the practice of fluoridation. This position
presumes the constancy of the environment in which policy decisions are made. Questions of public health policy are relative,
not absolute, and different stages of human progress not only will have, but ought to have, different needs and different means
of meeting those needs. Standards regarding the optimal level of fluoride in the water supply were developed on the basis of
epidemiological data collected more than 50 years ago. There is a need for new guidelines for water fluoridation that are based
on sound, up-to-date science and sound ethics. In this context, we would argue that sound ethics presupposes sound science.
Dr. Cohen has a PhD in political and moral philosophy from the University of Toronto. He is currently enrolled in the
dental undergraduate program at the University of Toronto.
Dr. Locker is professor and director of the Community Dental Health Services Research Unit, Faculty of Dentistry,
University of Toronto.
The views expressed are those of the authors and do not necessarily reflect the opinions or official policies of the
Canadian Dental Association.
1. McNally M, Downie J. The ethics of water fluoridation. J Can Dent Assoc 2000; 66(11):592-3.
2. Diesendorf M, Colquhoun J, Spittle BJ, Everingham DN, Clutterbuck FW. New evidence on fluoridation. Australian N Z J
Public Health 1997; 21(2):187-90.
3. Spencer AJ. New, or biased, evidence on water fluoridation? Australian N Z J Public Health 1998; 22(1):149-54.
4. Potter VR. Bioethics: Bridge to the Future. Englewood Cliffs: Prentice Hall, 1971.
5. Coggon D, Cooper C. Fluoridation of water supplies: Debate on ethics must be informed by sound science. BMJ 1999;
6. Higgs R. On telling patients the truth. In: Lockwood M, editor. Moral dilemmas in modern medicine. Oxford: Oxford
University Press; 1985.
7. Burt B, Eklund S. Dentistry, dental practice and the community. 5th ed. Philadelphia: WB Saunders Company; 1999.
8. Lewis DW, Banting DW. Water fluoridation: current effectiveness and dental fluorosis. Community Dent Oral Epidemiol
9. Locker D. Benefits and risks of water fluoridation. University of Toronto, Community Dental Health Services Research Unit;
10. McDonah M, Whiting P, Bradley M, Cooper J. A systematic review of public water fluoridation. University of York: NHS
Centre for Reviews and Dissemination; 2000.
11. Hawkins RJ, Leake JL, Adegbembo AO. Water fluoridation and the prevention of dental caries. J Can Dent Assoc 2000;
12. Slade GD, Davies MJ, Spencer JA, Stewart JF. Association between exposure to fluoridated drinking water and dental
caries experience among children in two Australian states. J Public Health Dent 1995; 55(4):218-28.
13. Heller KE, Eklund SA, Burt BA. Dental caries and dental fluorosis at varying water fluoride concentrations. J Public
Health Dent 1997; 57(3):136-43.
14. Clovis J, Hargreaves JA, Thompson GW. Caries prevalence and length of residency in fluoridated and non-fluoridated
communities. Caries Res 1988; 22(5):311-5.
15. Ismail AI, Brodeur JM, Kavanagh M, Boisclair G, Tessier C, Picotte L. Prevalence of dental caries and dental fluorosis in
students 11-17 years of age, in fluoridated and non-fluoridated cities in Quebec. Caries Res 1990; 24(4):290-7.
16. Ismail AI, Shoveller J, Langille D, MacInnis WA, McNally M. Should the drinking water of Truro, Nova Scotia be
fluoridated? Water fluoridation in the 1990s. Community Dent Oral Epidemiol 1993; 21(3):118-25.
17. Clark DC, Hann HJ, Williamson MF, Berkovitz J. Effects of lifelong consumption of fluoridated water or use of fluoride
supplements on dental caries prevalence. Community Dent Oral Epidemiol 1995; 23(1):20-4.
18. Spencer AJ, Slade GD, Davies M. Water fluoridation in Australia. Community Dent Health 1996; 13(Suppl 2):27-37.
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