Water fluoridation: one dentist’s reservations

A note on what this article is

This is an opinion piece. It sets out one clinician’s personal reflections on water fluoridation, including arguments on both sides.

It is not clinical advice, and it does not represent a recommendation against fluoride. The practice’s clinical position, set out elsewhere on this site, is that fluoridated water is safe and effective, and helps prevent decay at all ages — see the benefits of fluoride and fluoridated water: is it good for you?, which is the article that states that position directly. Reading both is the point.

Why this is awkward for a dentist to write about

It is problematic for any dentist to express opinions on water fluoridation. Pro-fluoride sentiment is easily dismissed as biased or arrogant. An anti-fluoride stance could be read as an attempt to drum up business.

So the topic tends to be avoided by exactly the people who see its effects most directly.

Where the author is coming from

Dr Pajouhesh was raised in the United Kingdom, where there was no water fluoridation at the time.

As a child he had serious problems with his own teeth, resulting in numerous visits for heavy treatment. Those experiences were confronting enough that they eventually led him to face his dental phobia by becoming a dentist. On that subject specifically, see dental anxiety, how can I ease my anxiety about visiting the dentist? and dental phobia: how do you give a virtually pain-free injection?.

Now, reflecting on his own two children’s wellbeing, he returns to the same question every time one of them lifts a glass of water.

The case for yes

Every dentist with professional experience in non-fluoridated regions has seen the decay rates there.

What that looks like: rampant decay on tooth surfaces where you would not ordinarily see decay — in children, in adults and in the elderly — at levels that kept a dentist occupied all day drilling out soft cavities and filling them. How does tooth decay develop? and the stages of dental decay describe the disease he is talking about, and why do I need a filling? the treatment.

Against that, his own children’s minimal decay rates are attributable to constant fluoride exposure. Their dental visits involve fun and health education rather than extraction forceps and anaesthetic needles. See children’s dentistry, when should a child first visit the dentist? and protecting your child from dental disease.

That is not a small benefit, and it is the argument that carries the most weight.

The case for no

Fluoride deposited into the water system reaches all living things, because life depends on water.

It is in the water we drink, and in the food we eat — entrenched in the food system. You cannot avoid it by drinking bottled water or eating certified organic food.

That raises questions he does not consider settled:

Accumulation. The amount added to the water supply is fixed and known. Where else is it accumulating, and by how much?

Route of delivery. Fluoride acts topically on the teeth. So why is it being swallowed, consumed and absorbed? Could there be side effects from lifelong absorption of an element the body stores? On the topical side of the argument, selecting a toothpaste — fluoride or non-fluoride?, choosing the right toothpaste and what can I do to strengthen my teeth? set out how topical fluoride is meant to be used.

Consent. Is water fluoridation a form of mass medication? The decision has been made on his behalf and his children’s, without an individual choice to decline.

Consistency. If Omega 3 can reduce diabetes and heart disease risk, and Vitamin B has broad health benefits, why is the public not mass-medicated with those?

Dose. Health training teaches that medication should be administered according to weight or body mass. So why is the same dose appropriate for a 10kg child and an 85kg adult? The point sharpens when you consider that a small child takes most of its hydration through water and milk.

Mottling. Why should a parent be comfortable with large white blotches on a child’s front teeth caused by fluoride exposure? Could a stringent programme of surface fluoridation have delivered the same low decay rates without a lifelong legacy of blotchy teeth? The condition he is describing is fluorosis: what causes white spots on teeth? sets out how it is told apart from the other causes of white marks, and what can and cannot be done about it afterwards. It is distinct from chalky teeth, which has a different cause again.

That last question is the most concrete of them, and it is the one most likely to be answerable with research.

The case for a better way

“As an individual, as a dentist, as a parent, I don’t have the answers to these questions.”

What he argues for is more public debate, and substantially more funding for research.

If there is a better way to fight dental decay while maintaining wellbeing and freedom of choice, we owe it to ourselves as a community to find it.

The measures that already exist, and that do not involve swallowing anything, are worth knowing about while that debate continues: the role of fissure sealants in children’s teeth, who is a suitable candidate for dental sealants?, how to encourage your child to brush their teeth, kids’ teeth cleaning tips and how does sugar affect your dental health? — since reducing the frequency of sugar is the one measure nobody disputes. For families, the Child Dental Benefits Schedule and how does the Child Dental Benefits Schedule operate? cover public funding for the preventive side.

If the whole-body framing of this question is what interests you, what is holistic dentistry?, the benefits of holistic dentistry and holistic dentistry describe the approach — and what it does not claim.

Where to go for the evidence

Anyone weighing this for their own family should read the position statements of the bodies that review the evidence directly — the National Health and Medical Research Council (NHMRC), the Australian Dental Association, and your state health department — rather than relying on any single opinion, including this one.

What the NHMRC review actually says

Several of the questions above have published answers, and the fairest thing an opinion piece can do is set them out. The NHMRC reviewed the research on water fluoridation in 2014–15, assessing studies published between 2006 and 2015 alongside the earlier 2000 and 2007 reviews, and published its conclusions in a 2017 public statement and an accompanying questions-and-answers document. Everything in this section comes from those documents and is attributed to the NHMRC, not to the author.

On the size of the benefit. The NHMRC found that water fluoridation reduces tooth decay by 26 to 44% in children and adolescents, and by about 27% in adults. Australia’s first scheme began in Beaconsfield, Tasmania, in 1953, and as at February 2017, 89 per cent of Australians had access to fluoridated drinking water.

On dose — the sharpest of the questions above. The NHMRC supports fluoridating within the range of 0.6 to 1.1 milligrams per litre, a range it describes as aimed at reducing tooth decay while avoiding any risk of dental fluorosis of aesthetic concern. The body-weight objection has a direct answer: the Nutrient reference values for Australia and New Zealand do set an Adequate Intake that varies by age and weight — 4.0 mg a day for an average adult male and 3.0 mg for an average adult female, and in children from 0.5 mg a day at 7 to 12 months to 1.1 mg a day at 4 to 8 years. The upper level of intake for an average-sized adult is given as 10 mg a day, which the NHMRC notes would mean drinking at least 10 litres of water a day at current Australian levels — a volume it describes as dangerously high for reasons that have nothing to do with fluoride.

On route of delivery. The topical mechanism is not in dispute. The NHMRC’s account is that fluoride in drinking water reduces demineralisation and enhances remineralisation, and that fluoridated water keeps low levels of fluoride in saliva and dental plaque all day, while the much higher concentration in toothpaste offers additional benefit. The two are presented as complementary rather than as alternatives — which is why the NHMRC’s answer to whether you should still use fluoridated toothpaste if you drink fluoridated water is yes.

On accumulation and other health effects. The NHMRC’s conclusion is that there is no association between community water fluoridation as practised in Australia and cancer — including osteosarcoma and Ewing sarcoma — or cognitive function and intelligence, or hip fracture; and no reliable evidence of an association with chronic kidney disease, kidney stones, atherosclerosis, high blood pressure, low birth weight, all-cause mortality, musculoskeletal pain, osteoporosis, skeletal fluorosis or thyroid problems. It is explicit about what that second phrase means: it uses “no reliable evidence” where it lacks confidence that the evidence reviewed is relevant to Australia or valid — because of small study numbers, weak designs, or uncontrolled confounders such as fluoride from other sources, socioeconomic status, or exposure to iodine or lead. On the overseas studies of intelligence specifically, its position is that they were conducted in countries where fluoride levels greatly exceed Australian levels and did not account for factors such as parental education and arsenic in the drinking water.

On mottling. Dental fluorosis is caused by high fluoride intake from multiple sources while teeth are developing inside the jawbone — usually from birth to six or eight years of age. The NHMRC reports that fluorosis in Australia has declined over the period in which fluoridation expanded, and links that decline to reduced exposure from other sources, particularly the availability and active promotion of low-fluoride children’s toothpaste. Where fluorosis is identified in Australia it is in most cases very mild or mild; moderate fluorosis is very uncommon and severe fluorosis is rare, and in children aged 8 to 14 the small amount of moderate and severe fluorosis is not statistically different between fluoridated and non-fluoridated areas. None of that makes a blotch on one particular child’s front tooth less irritating to their parent — and it is worth repeating that many of the white marks asked about in practice are not fluorosis at all.

On the mass-medication framing. The regulatory answer in Australia is that the Therapeutic Goods Administration does not require fluoride compounds added to drinking water to be registered as medicines when they are used to prevent decay, and does not schedule them as drugs or poisons at optimal levels. The NHMRC also classifies fluoride as a nutrient: the nutrient reference values describe it as classified as essential to human health because of its role in preventing decay.

On consent. The NHMRC does not claim that individual consent is obtained. Its argument is that the asymmetry runs the other way — that a greater effort is required to opt in to fluoride where there is no community water fluoridation than to opt out of it where there is. Opting out is possible: rainwater collected in domestic tanks contains no fluoride, most bottled water is not fluoridated (Australian food regulations permit adding it within 0.6 to 1 mg/L, and the contents must be labelled), and distillers and filters using ion-exchange resins, activated aluminium or reverse-osmosis membranes remove most of it. The NHMRC’s position is that each of those involves effort and expense, and that removing fluoride is neither necessary nor desirable. On organic produce specifically, it states that fluoridation does not affect a producer’s ability to obtain or retain certification, because under the Australian Certified Organic Standard all drinking water is permitted as a conventional, non-certified ingredient.

On cost. For every dollar spent on fluoridation in Australia the NHMRC cites savings of between $7 and $18 in avoided treatment costs, and reports studies finding that Victoria saved about $1 billion over a 25-year period following its introduction.

Where that leaves the argument. It does not dissolve the consent question, which is political and ethical rather than scientific, and the NHMRC treats it as such — it answers that one with an argument about balancing community health against individual choice, not with data. But on dose, accumulation, mottling and the medication framing there are published answers, and they are considerably more specific than the debate usually is.

If you have specific concerns about your own or your children’s fluoride exposure, raise them at your next appointment. Fluoride exposure from all sources is something a dentist can assess and advise on individually — understanding your treatment and how often should I go to the dentist? cover the visit at which to raise it, and five questions you’ve always wanted to ask your dentist is a reminder that awkward questions are fair game. Fluoride supplements in drops or tablet form are a separate matter again: the NHMRC’s advice is that they should only be used on the advice of an oral health professional, and it notes that they are no longer readily available in Australia.

Common questions

This site publishes two articles that reach different conclusions. How am I supposed to decide?

By separating the parts of the question that have published answers from the part that does not — because they need different kinds of reasoning.

The empirical questions have been reviewed. How much decay fluoridation prevents, whether it is associated with cancer, cognition, bones or kidneys, what causes fluorosis and whether it has increased — those are settled to the extent that a large evidence review can settle anything, and the findings are set out above with the NHMRC's own wording. You do not have to take a clinician's word for any of them; the public statement is a public document.

The consent question has not been, and cannot be. Whether a community-wide measure that individuals cannot opt out of without effort is justified by its benefits is an ethical and political judgement, not a scientific one. The NHMRC answers it with an argument about balancing community health against individual choice — which is a position, not a finding. Reasonable people land in different places on it, and a dentist's opinion carries no special authority there.

So the practical way through is to accept the evidence on the measurable questions, decide the ethical one for yourself, and then ask a third question the debate usually skips: what is the actual decay risk in my household? A family with no decay history, low sugar frequency and good brushing has less at stake either way than a family with active decay, a dry mouth, or a child who has already needed fillings. The fluoride argument matters most precisely where the risk is highest — which is why it is worth having the risk assessed rather than assumed. See how often should I go to the dentist?

If I would rather not rely on fluoridated water, what actually works instead?

Quite a lot, and the independent guidance is specific rather than vague. None of it requires you to settle the argument above first.

The sugar threshold is the one nobody disputes. The World Health Organization's position is that limiting free sugars to less than 10% of total energy intake — and ideally to less than 5% — minimises the risk of dental caries throughout the life course. Free sugars is a defined term and wider than people expect: all sugars added by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and fruit juices. Fruit juice counts.

Frequency matters as much as quantity. The Australian Dental Association's policy on diet and nutrition states that "the form, frequency, timing and total amount of sugar intake are significant in the initiation of the caries process", and asks for special emphasis on "snacking on sugary beverages and/or sugar-rich foods that have limited nutritional value". One dessert does less damage than the same sugar spread across six grazing episodes, because each exposure restarts the acid cycle.

Two specific ADA points worth acting on. It recommends calcium-rich foods and drinks such as milk, cheese and some fish as the preferred dietary calcium source. And for infants, it says sleeping with sweetened dummies, food or bottles containing sugar — including milk and fruit juices — should be discouraged. That last one accounts for a large share of severe early childhood decay and has nothing to do with water.

Topical fluoride is still available to you if you want it. The WHO names removal of plaque by toothbrushing with a fluoride toothpaste containing 1000–1500 ppm as one of the three levers alongside sugar restriction and adequate fluoride exposure. If the objection is to swallowing fluoride rather than to fluoride itself, toothpaste used properly — a small amount, spit rather than rinse — delivers the topical benefit without the systemic route. That distinction is the practical core of the author's own argument above.

And whatever you decide, have the decay risk assessed rather than guessed. Sealants for deep grooves and professionally applied products are prescribed on the basis of an examination, not from a shelf — see who is a suitable candidate for dental sealants?

How do I find out whether my own water is fluoridated, and what should I do if it is not?

Your state or territory water authority is the source for what is in your supply, and your state health department for the policy behind it. Neither is hard to reach and neither charges.

The cases where the answer is probably no, or not much:

What to do about it is the same either way: say so at your next appointment. It changes the decay-risk assessment and the products that may be recommended, and that is a conversation rather than a lecture.

One thing not to do on your own initiative: fluoride supplements in drops or tablets. The NHMRC's advice is that these should only be used on the advice of an oral health professional, and it notes they are no longer readily available in Australia. The reason is the fluorosis risk in young children, whose teeth are forming — which is the one harm on this page everybody agrees is real.

Related reading

Practical details

Written by Dr Kia Pajouhesh, managing director of Smile Solutions. The views expressed are his own.

Smile Solutions, Level 1, 220 Collins Street, Manchester Unity Building, Melbourne VIC 3000 — getting here. Phone 13 13 96, contact us, or theteam@smilesolutions.com.au. Monday–Friday 8.00am–6.00pm, Saturday 8.30am–1.30pm, Sunday by appointment.

Specialist registration can be verified on the AHPRA register, or by calling 1300 419 495. The practice’s registered specialists are identified as such within the full team.

Published 26 February 2015. Opinion only; it does not constitute clinical advice and does not replace advice from your treating practitioner or public health authorities. Figures attributed to the NHMRC in this article are drawn from its 2017 public statement on water fluoridation and human health in Australia and the accompanying questions-and-answers document; check the current publications for any update. Figures attributed to the World Health Organization and the Australian Dental Association are those publishers’ own.

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