Dental Fluorosis |
Is it true that up to 80 per cent of children living in fluoridated areas suffer from dental fluorosis?
BFS suggested answer
No. In the UK unsightly dental fluorosis is rare. However, tooth decay is a huge problem which affects millions of children. Ugly black holes in children’s teeth caused by decay are the ugliest problem of all.
BFS suggested answer refuted
Dental fluorosis, no matter how slight, is an irreversible pathological condition recognised by authorities around the world as the first readily detectable clinical symptom of previous chronic fluoride poisoning. To suggest we should ignore such a sign is as irrational as saying that the blue-black line which appears on the gums due to chronic lead poisoning is of no significance because it doesn’t cause any pain or discomfort.
Dr Geoffrey Smith1
There are many disorders, considered in other chapters, that those opposed to fluoridation claim are caused by fluoride and that those in favour of fluoridation refuse to accept are related to it. But there is one very obvious condition caused by fluoride that is not disputed. That is the staining or mottling of teeth called dental fluorosis.
While there is agreement on both sides that fluorosis exists, and that fluorosis is an undesirable side effect of fluoride use, the two sides differ in their attitudes to it. Those in favour of fluoride say that fluorosis is ‘a cosmetic issue, not a health problem’;2 that in its mildest form the pearly-white patches of fluorosis actually make teeth ‘more attractive than teeth without fluorosis’.3 Anti-fluoridationists take a different view: that fluorosis is a visible sign of fluoride poisoning.
Who is right?
Dental fluorosis was first reported by two dentists in 1916.4 By 1931, there was extreme concern about what was called ‘Colorado brown stain’ and ‘Texas teeth’. In that year three independent groups of scientists5, 6, 7 showed conclusively that the areas with this condition had high levels of fluoride in their water.
Reports from China,8 Argentina,9 Britain,10 Italy11 and Japan12 also showed significant levels of fluorosis in children drinking fluoride-contaminated water. Many of these reports were from areas with levels of fluoride in their water of the order of 8 or more parts per million. But then it was noticed that fluorosis was not restricted to areas with such high levels. In a 1982 study carried out by the University of Rochester, USA, fluorosis was seen in 28 per cent of children aged between eleven and thirteen, yet they were drinking water with the recommended level of 1 ppm.13 Later studies showed a similar picture across North America, with an average fluorosis in the school population of 40.5 per cent,14 while it was as high as 58 per cent in Quebec,15 and 69.2 per cent in Nova Scotia.16 Researchers in the Netherlands reported that 74 per cent of children examined exhibited fluorosis in a slight to moderate degree.17 They say that more teeth were affected and the degree of mottling was higher when children started to use fluoride at an earlier age. By 1989, over 80 per cent of 12- to 14-year-old children in Augusta, Georgia, had fluorosis.18
Dental fluorosis also affects a large proportion of children in the fluoridated areas of Britain.19 It is particularly easy to spot in large fluoridated cities like Birmingham, where the vast majority of children seem to suffer from it.
With the coming of fluoridated toothpastes, infant formulas, and commercially prepared beverages – in particular, soft drinks such as colas – made with fluoridated water, the incidence of dental fluorosis has increased, even in unfluoridated areas.
There are regular warnings in the dental press, such as: ‘Dentists should be aware of the fluoride concentrations of the drinking water of their child patients, be they municipal or bottled drinking water, when prescribing fluoride supplements,’ or ‘Practitioners should estimate fluoride ingestion from all these sources if considering systemic fluoride supplementation.’ But how can dentists – or anyone else – make any form of meaningful estimation when no official body measures individual intakes of fluoride?
It took fifty years, after the first fluoridation scheme was introduced, for the American Dental Association to acknowledge that fluorosis was a problem. ‘This has led to efforts to identify the cause or causes,’ they say.20 But we all know what the cause is: it’s no secret, we’ve known it for almost a century – it’s fluoride! The author suggested that dental practitioners could have an important impact on reducing the prevalence of enamel fluorosis by guiding the public toward the most appropriate use of fluoride products. Of course they could. The question is: Why don’t they?
Breast is best
A major source of fluoride in infancy is infant formulas. Whether or not they are made with fluoridated water, infant formulas have been implicated as a risk factor for fluorosis in several studies. Doctors in Melbourne, Australia, found that the fluoride content of commonly used infant formulas in Australia ranged from 0.23 to 3.71 ppm if the formulas were milk-based and from 1.08 to 2.86 ppm if they were soy-based.21 When the formulas were reconstituted, according to the manufacturer’s directions, with fluoridated water, infants’ intakes were as much as three times the recommended upper limit.
On the other hand, breast milk contains very little fluoride. Because fluorine is such a ubiquitous element, practically everything we eat or drink contains some fluoride. During our evolution we must have developed a tolerance for small quantities of it. But no matter how much is found in the foods and water a mother drinks, it seems to be filtered out in some way, for very little, 0.01 ppm on average, is found in breast milk.22 This indicates that nature has designed things so that infants are protected from fluorides in their early years.
Fluoride supplements
For areas that do not have the ‘benefit’ of fluoridated water, parents have been persuaded to give their offspring fluoride pills, drops or similar supplements. The effects of such supplementation on dental caries and dental fluorosis was measured in 160 children in two age ranges: 7–9 years and 11–14 years. They all had lived from birth in a region with low fluoride levels in the drinking water, and had been offered sodium fluoride supplementation in the form of drops for daily use. Inevitably some children complied with the recommendations religiously, while others didn’t. The results showed no statistically significant differences in dental caries between the regular and irregular users of fluoride supplementation. Considerable dental fluorosis was found in 38–63 per cent of the children in both groups.23
There have been many calls for the use of fluoride supplements to cease. In 1991 the US government published its estimated intake of fluoride for Americans, which was as much as 120 per cent over the assigned ‘optimal dose’ of 1 mg per day in unfluoridated areas and a huge 605 per cent in fluoridated areas. The government said that its data indicated that dentists should not prescribe supplements.24 The Canadian Dental Association recommends ‘No fluoride supplements for children under seven years old’.
It seems that this entreaty was unsuccessful, as subsequently there have been more calls for the cessation of fluoride supplementation. In 1994 Dr Brian Burt of Ann Arbor, Michigan, told the Dietary Fluoride Supplement Conference of the American Dental Association, in Chicago, Illinois, that there are three reasons why the use of supplements was inappropriate among young children in the United States:25
•The evidence for the efficacy of fluoride supplements in caries prevention was not strong.
•Supplements were a clear risk for dental fluorosis.
•Fluoride did not protect teeth that had yet to appear.
The last reason is particularly relevant to water fluoridation. The proponents of fluoride say that it has its greatest effects while teeth are growing. Indeed, after teeth have grown and matured, fluoride cannot be incorporated. Bones in the body are dynamic structures in that their materials are constantly being replaced. For that reason, fluoride is incorporated throughout life. This is not the case with teeth. Once they have grown and matured, they are static. After about the age of twelve, therefore, only a topical application – toothpaste, gels, and so on – can direct fluoride to where it may do any good.
Calls for supplementation to cease were not confined to America. In 1996 Dr P.J. Riordan, of Western Australia, pointed to the substantial evidence that supplements caused dental fluorosis even when used in accordance with recommendations for infants and small children.26 He warned:
Supplements should no longer be recommended for caries prevention in children in areas with little fluoride in water . . . If supplements are recommended for children, a more cautious dosage schedule should be used. The fact that supplements have been recommended uncritically for many years on the basis of inadequate research raises questions about the standards of dental science.
It is clear that any benefit from supplement use is marginal at best, while the risk of fluorosis is high. Dr Burt stated that ‘[t]here is evidence that the public is more aware of the milder forms of fluorosis than was previously thought, so dental policies should be aimed at reducing fluorosis’. I am disturbed by the reason Burt gives – that the public is more aware of fluorosis. Shouldn’t health be the main criterion? He continued: ‘The risks of using fluoride supplements in young children outweigh the benefits. Since there are alternative forms of fluoride to use in high-risk individuals, fluoride supplements should no longer be used for young children in North America.’
Toothpaste
Systemic use of fluoride from water, food and supplements has not been shown to have a statistical benefit in terms of reduction of caries but has merely led to a dramatic increase in fluorosis. What evidence there is suggests that a topical application of fluoride directly to the tooth’s surface may be more effective at combatting decay. But does this also increase the risk of fluorosis? Dr M.C. Skotowski and colleagues set out to answer this question in Iowa City in 1995. A total of 157 children aged eight to seventeen, who sought dental treatment in a university paediatric dental clinic, were examined for dental fluorosis. The children’s parents were asked to complete fluoride history questionnaires to assess exposure to fluoride during the first eight years of life. Finding fluorosis in 72 per cent of the children, they concluded that ‘[t]his study provided evidence that increased use of fluoride toothpaste may be a risk factor for dental fluorosis. The results suggest prudent use of dentifrice by young children to minimise the risk of fluorosis.’27
How much fluoride does it take to cause fluorosis?
The answer seems to be: very little. The recommended ‘optimal’ level of 1 ppm has been shown time and time again to cause fluorosis. There is no doubt about this; even the pro-fluoridationists admit that fluorosis can occur at this level.
But does it matter?
Dentists say that fluorosis is merely a minor cosmetic condition. But it is not ‘minor’ if you happen to suffer from it. Fluorosis strikes when a child is at a psychologically vulnerable age. Children with badly stained (fluorosed) teeth tend to be shunned, bullied or ridiculed by their peers. No child should have to endure that. At an international conference on fluoridation in Birmingham in 1995, evidence was presented that ‘even mild [fluorosis] was associated with psycho-behavioural impacts’.28
It would be bad enough if the harm that fluorosis does stopped at mere childhood intolerance, but it doesn’t. Dental fluorosis is not merely a stain on teeth: it is a visible sign of damage to bones and other tissues throughout the body – damage that cannot be seen.29
Ingested fluoride is absorbed mainly through the stomach and intestine into the bloodstream. The fluoride is then carried to developing tooth buds, where the fluoride is incorporated into a tooth’s enamel. Once there, interaction with the developing crystals initiates the replacement of the tooth enamel’s normal crystalline composition, hydroxyapatite, by fluorapatite, a related crystal that incorporates the fluoride, thus changing the tooth’s chemical structure. As fluorapatite is more resistant to decay than hydroxyapatite, this modification of the tooth’s chemistry is believed to lead to a reduction in dental caries.
But while fluorapatite may be harder and more resistant to decay, it makes the tooth’s enamel more brittle. As fluorosis increases, the subsurface enamel all along the tooth becomes increasingly porous (hypomineralised), leading to extensive mechanical breakdown of the surface.30 Even with very mild fluorosis, the brittleness makes dental work more difficult and more expensive – a particularly important consideration in undernourished children, who are at a much higher risk of developing dental fluorosis, as their parents are less likely to be able to afford the sometimes expensive cosmetic repairs needed.
The American Dental Association reported that dentists make 17 per cent more profit in fluoridated areas than in unfluoridated areas.31 This finds support in fluoridated Birmingham, England: although the population has remained fairly constant over the past few decades, the number of dentists practising there doubled over a twenty-year period.
Conclusion
Proponents of water fluoridation admit that those who drink water containing fluoride will suffer fluorosis of their teeth. The only difference between the pro- and anti-fluoride camps is the significance they attach to this fact.
Dental fluorosis is a permanent disfigurement. That is undisputed. Unfortunately for those affected by dental fluorosis, the official position is that their unsightly condition is considered to be merely cosmetic and not an adverse health effect. For this reason, in Britain, for example, treatment cannot be obtained free on the NHS, which seems churlish, when it was the health authorities that caused the problem in the first place.
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2.Dental fluorosis in perspective: The good, the bad and the ugly. British Fluoridation Society briefing. November 1997.
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18.Schenectady Gazette Star, 5 August 1989.
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24.Review of fluoride: Benefits and risks. US Department of Health and Human Services, 1991; 1–134.
25.Burt BA. The case for eliminating the use of dietary fluoride supplements among young children. Abstract of paper presented at Dietary Fluoride Supplement Conference, American Dental Association, Chicago, Illinois, USA, 31 January – 1 February, 1994.
26.Riordan PJ. The place of fluoride supplements in caries prevention today. Aust Dent J 1996; 41: 335–42.
27.Skotowski MC, Hunt RJ, Levy SM. Risk factors for dental fluorosis in pediatric dental patients. J Public Health Dent 1995; 55: 154–9.
28.Bob Woffinden. Clear and present danger. The Guardian Weekend on The Guardian website, www.guardian.co.uk, 7 June 1997.
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31.Douglas BL, Wallace DA, Lerner M, Coppersmith SB. Impact of water fluoridation on dental practices and dental manpower. J Am Dent Assoc 1972; 84: 355–67.