How Fluoride Harms Rather Than Helps Teeth

The case for the fluoridation of drinking water

I was in the village shop recently when the school bus stopped outside. Within seconds it disgorged a large number of teenage children. They swept into the shop to strip the shelves of sweets like locusts. It was obvious that they had no thought for the harm they were doing to their health, their waistlines or their teeth. The last of these is what the British Dental Association says it is trying to combat by adding fluoride to the country's tap water: fluoride, they say, reduces tooth decay.

Dental decay begins as soon as the first teeth start erupting and are contaminated by sugary and starchy foods. Caries are caused by bacteria. The most common bacterium implicated in the cause of caries is Streptococcus mutans. The development of a cavity in a tooth proceeds in the following manner. The bacteria first gain attachment to the tooth surface by making a starchy "glue". Once attached, and given a suitable food supply, the bacteria thrive and multiply, producing colonies which we know as dental plaque. Within the plaque, millions of microbes ferment carbohydrates — sugars and starches. The waste product of this fermentation is a dilute acid. And it is this acid that eats away, or demineralises, the surface layers of the tooth allowing in other food particles and bacteria to decay the underlying material of the teeth.

Dental caries is not a new phenomenon.

Skulls from the period of our history before the cultivation of grains — wheat, rice, barley and so on — show few signs of carious (decayed) teeth. However, after then we see its emergence in many parts of the world. The highly cultured Sumerians of around 5,000 BC and the ancient Egyptian rulers wealthy enough to be buried in the pyramids, all have signs of the dental decay we see today. Significantly, the poorer and lower classes do not.

For seven thousand years, the wealthy always fared worse that the poor as far as tooth decay was concerned. But in the nineteenth century ad, and with an ever-quickening pace in the twentieth, reductions in the cost of producing sugar led to a huge increase in the amount we eat. At the turn of the nineteenth century we each ate, on average about 1 kg (2 lbs) of sugar. It is now around 60 kg (130 lbs). As its price dropped and it became more available, sugar and products which contain sugar became regarded as necessary, indeed essential, foods. More recently, starchy foods like white bread, polished rice and pasta were consumed in ever increasing quantities. And as a consequence the incidence of dental caries soared in many Western countries. As sugary and starchy foods are significantly cheaper than foods of animal origin which are high in protein and fats, they are eaten in greater quantity by the poorer element in our societies. Thus the decay which was common in the rich but rare among the poor, shifted to become a disease more associated with poverty.

At the same time, those tribes that we tend to think of as poor, because of their lack of the material possessions we enjoy, but whose diets are restricted to meat, fish and berries — the Eskimo, Maasai, Hunza, Siberians and others — have remained caries free. For it is sugars and refined starches alone which are the fertile breeding ground of the bacteria which rot teeth. This is vividly illustrated by a comparison between the inhabitants of the two sides of Greenland. Until about 200 years ago all Eskimos were free of dental caries. Now, those in the western areas with access to ice-free harbours for much of the year, and supplied with "civilised" refined carbohydrate foods, have dental caries, while those on the largely iced-up eastern side of Greenland, where the traders cannot get and, thus, are uncontaminated by western diet, have healthy teeth.

Similarly, during World War II, the incidence of dental decay fell dramatically in occupied Denmark and Norway, where sugar was scarce, while it remained high in neutral Sweden, where sugar remained readily available.

But while caries increased to the proportions we see today in many industrialised countries, there were areas within these countries, where children eating the same foods did not suffer the same high levels of dental disease. On investigation it seemed that the children spared the suffering of toothache were the ones who lived in areas which had naturally-occurring calcium fluoride in their water supplies. And it was suggested that it was this compound which was responsible for the reduction of caries. Thus was fluoride seen to be beneficial in the early part of the century.

Why fluoride?

Fluorine, a member of a group of elements called halogens, is the thirteenth most common element in the earth's crust. Elemental fluorine is a pale yellow gas and a deadly poison. The most reactive of all the halogens, fluorine will bind with almost any other element to form a fluoride. Elemental fluorine does not occur in Nature; it is found only in compounds with other elements. It has a particularly strong affinity for calcium with which it forms a strong bond. In its natural state fluorine is commonly found as calcium fluoride.

During the last years of the nineteenth century the inhabitants of several areas of the USA had mottled teeth. In one it was called "Texas teeth", in another, "Colorado brown stain". Although this condition was unsightly, it was noticed that children with it tended to have fewer cavities in their teeth. Investigations in the USA showed that this mottled enamel (we now call it "fluorosis") was caused by naturally occurring calcium fluoride in the drinking water. It was not long before the observation of the staining effects of fluoride on tooth enamel led to suggestions that the fluoride might also be the agent responsible for conferring protection against dental caries.

Fluorides are believed to help to prevent dental caries in several ways:

Systemic fluoride strengthens teeth. Fluoride has a strong affinity for calcium, the material from which bones and teeth are made. Systemic fluoride, that is fluoride ingested in food or water, is absorbed, mainly through the stomach and intestine, into the bloodstream where it is attracted to bones, teeth and any other calcium in the body. In young children whose milk teeth or, later, permanent teeth are growing, the fluoride is carried to developing tooth buds. Here the interaction with the developing crystals initiates the replacement of the tooth enamel's normal crystalline composition ( hydroxyapatite ) with a related crystal which incorporates fluoride ( fluorapatite ) while they are growing. As fluorapatite is believed to be stronger and more resistant to decay than is the more normal hydroxyapatite, the claim is that teeth of children who drink fluoridated water or are given fluoride supplements are less likely to develop caries. It should be borne in mind, however that, once fully formed, tooth enamel is static — unlike bone, it doesn"t undergo metabolic changes. Thus systemic fluoride can only be incorporated into teeth during the growing period. That is up to about the age of twelve. Water fluoridation will not strengthen older teeth.

Fluoride helps to remineralise teeth. The acid produced by bacteria breaks down tooth enamel into its component chemicals, which include the tiny amounts of fluoride that had reached the surface of the teeth when it was incorporated as the teeth developed. Surrounded by plaque this fluoride builds up in the plaque. As the concentration of fluoride in the plaque increases, the bacteria's metabolisms slow down and they consume less sugar and starch. Less consumption means less acid is produced, and less acid means less decay. Eventually, it is claimed, the fluoride level becomes high enough to kill the bacteria. It is thought that some of the dissolved minerals may be reincorporated back into the teeth.

Topical fluoride kills decay-causing bacteria. There is some evidence that fluoride retards the development or the activity of decay-causing bacteria. All living cells, whether human, animal, vegetable or bacterial, are extremely sensitive to fluoride which, above a certain concentration, is extremely poisonous. At levels as low as 0.19 ppm (parts per million) fluoride interferes with certain of the S. mutans bacterium's essential metabolic enzymes; between 4 and 20 ppm it can cause S. mutans to mutate; and at 20 ppm or above it is lethal to the bacterium. Thus fluoride, a powerful antibacterial agent can be painted onto teeth (this is called a topical application) to kill the bacteria there. Toothbrushing with a fluoridated toothpaste, or a fluoride mouthwash, do the same job.

Thus the claimed benefits from fluoride can come from drinking water or eating food that contains fluoride as a child up to the age of twelve, having teeth painted (a "topical" application) with a fluoride gel, or using a fluoridated toothpaste or mouthwash later in life.

Supporting studies

A study in Hagerstown, Maryland USA, published in 1940 was one of the first large-scale investigations into dental caries. It was a study of the entire school population of the town — 4,416 children. Its authors discovered that by the age of six, fifty percent of the boys and fifty-six percent of the girls suffered from dental decay; and by the time they were fourteen, the rates had risen to ninety-five and ninety-six percent respectively.

The first fluoridation of public water supplies was begun in 1945 in Grand Rapids, Michigan, USA and was quickly followed by similar programmes at other sites across the USA. Since then it spread throughout the (mainly English-speaking) world. Fluoridation was first introduced to Britain as part of an experimental programme in 1955 before being adopted at other sites around the country in the 1960s. But in Britain fluoridation has not been widely adopted. At present only about nine percent of the British population, who mostly reside in either the West Midlands or Northeast, drink artificially fluoridated water.

In Britain too, there were studies which purported to demonstrate that fluoride in the water resulted in a reduced incidence of decay. In an extensive study, Hartlepool, a town with a naturally-occurring fluoride level of 2 parts per million, was compared to York which was not fluoridated. It was quite clear that fluoridated Hartlepool had far fewer carious teeth than unfluoridated York. The author ascribed this to the fluoride in Hartlepool's water. And without any other knowledge of the two towns, one could not argue against the findings. They appear quite conclusive.

Although fluoride was by now believed by many to be beneficial in terms of tooth decay, there was still the problem of the unsightly staining. It was considered that the fluorosis must be the result of too much fluoride in the water and so an "optimal" amount, which would confer benefit without the risk of fluorosis was decided upon: it was one milligramme per litre of water or one part per million (1 ppm). Above this concentration the risk of fluorosis was considered to outweigh the benefits of dental protection.

In light of such evidence major public health programmes around the world were initiated around the middle of the century to add fluoride to drinking water where it was considered deficient, i.e. less than 1 ppm.

And it couldn't be started too soon as the advertisement at Figure 1 demonstrates.

The case for the fluoridation of drinking water rests simply on this one perceived benefit: systemic fluoride helps to prevent dental caries in children up to the age of 12.

The Case Against Water Fluoridation

In 1969, the 22nd World Health Assembly passed a resolution recommending member states to "fluoridate water supplies where practicable in order in order to prevent dental caries". They also recommended that member states study other methods of using fluorides to protect dental health. They further called upon the Director-General of WHO to encourage research into the causation of dental caries, the fluoride content of diets, the mechanism of action of fluoride at optimal levels in drinking water and the effects of greatly excessive intake of fluoride from natural sources.

In January 1974 the executive board, apparently noting that after five years nothing had been done, instructed the Director-General to present a report to the 28th World Health Assembly in 1975.

When presented, this report was notable for the fact that it appeared to be merely a piece of propaganda for fluoridation. The question of what was an optimal level of fluoride ingestion, which is obviously fundamental to fluoridation of water, was entirely ignored. It contained no research into the of causation of dental decay, apart from acknowledging that "there has been a rapid increase in the magnitude of the caries problem in the developing countries as their populations begin to ingest a diet of more refined foods". This was nothing new as it had long been known that this was the reason why dental decay is rampant in the developed countries. Nevertheless, the WHO did not propose any action on this. Neither did the report contain anything on the other research subjects which the 1969 assembly had asked for. There was merely a proposal that some research should be done by somebody sometime in the future.

Despite the shortcomings the 28th World Health Assembly passed a resolution, the preamble to which stated that sufficient information on the safety and effectiveness of the use of fluorides as a method to prevent dental care use had already been obtained and they recommended that WHO should undertake the programme proposed by the director-general and shall promote approved methods for the prevention of dental care use especially by optimisation of the fluorides content of water supplies. The important question, of what (if any) was an optimal intake of fluoride remained unanswered.

Money down the drain — literally

One of the WHO's findings was that this preventative programme could result in more than 30-fold saving. This has since been disproved. Far from saving money, fluoridation has been shown to be literally throwing money down the drain. It is recognised by both sides of the argument, that the only people to benefit from water fluoridation, are children up to the age of about twelve. But it is estimated that less than one percent of all tap water is drunk by children of this age group. Most treated tap water is used by industry, for washing, for watering gardens, or is drunk by adults. Thus for every pound spent on water fluoridation, less than one penny reaches its target. Added to this waste are the extra dental costs necessitated by more complicated and expensive dental work that fluorosed teeth require. Examples of this are revealed by regional analyses of dental health expenditures (see table). Not only are there more dentists in fluoridated areas, the amount spent per head of the population is greater.

The most critical way to assess the effectiveness of fluoridation is to examine how much money is spent within Regional Health Authority boundaries. For the purpose of this exercise, three regions have been chosen for close examination of dental health costs. The picture that emerges from artificially fluoridated districts is that more fluoridation usually results in higher expenditure.

Notes to Table: In the table above, fluoride level shows the proportion of a population affected and the level of fluoride received. Optimal means the population received fluoridated water at a concentration of greater than 0.7 ppm. Expenditure is the sum of all receipts received for 1997 divided by the size of the population thus giving the average cost of dentistry per person. Dentists are those who were practising at the end of 1996 and the ratio is based on the size of the total population divided by the number of dentists. The population levels are estimated at mid-1996 levels.

• East Anglia has no artificial fluoridation schemes in place, but some water contains a noticeable amount of naturally occurring fluoride. It is important to consider the impact of natural fluoride on a population because of the claim that natural fluoride is better than artificial fluoride. Observations in this region do not support that claim.
• Northern region is home to two flagships of fluoridation: Newcastle and Gateshead. Both fluoridated since 1968, this allows us to compare adult expenditure. Both have the most dentists and the highest expenditure per head of population anywhere in the region. The only other major industrial town is Sunderland, which is also the only genuine non-fluoridated part of the region. Sunderland wins on all counts: dentistry is less expensive and there are fewer dentists per head. Why is it that Newcastle and Gateshead have so many extra dentists if, as they claim, fluoridation reduces the need for them?
• West Midlands . Districts in this region are the "shining" examples of the benefits of fluoridation, with Birmingham as the jewel in the crown. But expenditure in Birmingham is significantly higher than in less fluoridated Wolverhampton (all areas have some fluoridation). Wolverhampton is now 100% fluoridated. It will be interesting to see how expenditure levels change and how many more dentists are drafted into the city to improve dental health.

Benefits of fluoride on dental caries are not apparent

The claims of benefit for fluoride lie solely in its supposed ability to protect children's teeth from the effects of caries-causing bacteria. But just how strong is the evidence to support this contention as far as fluoridating drinking water is concerned?

We often hear statements by proponents of fluoridation to the effect that "more than 50 years of research and practical experience have proved beyond a reasonable doubt that fluoridation is effective in preventing tooth decay. Hundreds of studies have demonstrated reduction in tooth decay of 60-70% in communities with either natural or controlled fluoridation". But it is very difficult to find proof of such statements, as the most recent investigations of the status of children's teeth have found little benefit from living in a fluoridated area. Workers at the Turner Dental School in Manchester found no significant benefits on tooth decay with up to 2 parts per million of fluoride in drinking water. The Harvard School of Dental Medicine also reported that fluoride had no beneficial effect.

These two studies were conducted on rats but a similar lack of benefit has also been demonstrated in human studies.

Initial Studies Invalid

It was Dr. Trendley Dean, "the father of fluoridation", who first hypothesised that fluoridation would protect teeth from cavities. It was also he who declared that it was safe. In 1945 Dean established the first trial of fluoridation of the water supply in Grand Rapids, Michigan. Since that time, however, he has twice confessed in court that statistics from the early studies, allegedly supporting the use of fluoridation in community water systems, were invalid.

The first study not supporting the use of fluoridation was published in the Journal of the American Dental Association 1953. In a comparative study of tooth decay in 12-14 year olds in six Arizona cities, no reduction in decay and filled or missing teeth due to fluoridation could be observed. . and 1955. The second compared teeth of the residents of Cameron, Texas whose water contained 0.4 ppm of natural fluoride with those of Bartlett, Texas whose water contained 8 ppm of fluoride. The incidence of tooth decay was found to be no different between the two towns.

A study in Arizona published in 1993 of tooth-decay rates in 12 to 14 year olds in high- and low-fluoride areas found no significant difference between them.

Caries declines in unfluoridated areas

Dennis H Leverett, chairman of the Department of Community Dentistry, Rochester, New York, published a table in 1982 (Table 2) demonstrating that the dramatic declines in dental caries, which have been attributed to fluoride use, have also happened in unfluoridated areas.

The US National Institute of Dental Research figures for over 39,000 children from 84 locations in the USA indicated no difference in the numbers of decayed, missing and filled teeth (DMFT) between those who lived in fluoridated, partially-fluoridated or non-fluoridated communities. Dr. Bette Hileman stated: "The average decay rates for all children aged 5-17 were 2.0 teeth for both fluoridated and non-fluoridated areas. The Director of the Division of Dental Health Services for British Columbia showed that DMFT for both fluoridated and non-fluoridated areas was falling — but the areas which had the fewest bad teeth were those which were not fluoridated. And a report from Holland stated: "Dutch scientists found essentially no reduction in caries when the fluoride users and non-users had been carefully matched"

Dr. Albert Schatz Ph.D, co-discoverer of streptomycin, a drug which has saved millions of lives, is a respected scientist. In the early 1960s Dr Schatz studied the effects of water fluoridation in Chile. His work demonstrated that fluoride did not reduce caries, it merely postponed them by an average of 1.2 years. He also showed that fluoride increased death rates. In 1964 Dr Schatz wrote to the editor of the Journal of the American Dental Association (JADA) with a view to publishing his findings. The editor did not reply. In the first three months of 1965, Dr Schatz sent three copies of his report to JADA. They were all refused and sent back unopened. Dr Schatz says:

"Such a response is typical of the proponents of fluoridation. The professional sanctions for opposing fluoridation can be severe, and it is best not to even acknowledge evidence of harm or ineffectiveness."

The illusion that fluoride prevents dental caries

That "decreases" in dental caries reported from fluoridation trials may be merely a statistical artefact due to a delay in the onset of the caries process has been considered many times. North Shields and South Shields are very similar towns on opposite sides of the River Tyne. But, where South Shields water was naturally fluoridated at 1.4 ppm, North Shields water contained little or no fluoride. In 1948 the late Robert Weaver, then Senior Medical Officer to the Ministry of Education, compared the two towns and found that the amount of dental caries in the people of South Shields was no different from those living in North Shields. South Shields" fluoridated water, he found, merely delayed the onset of caries by about three years. Such a delay appeared to show benefits when children in fluoridated areas were compared with those of the same age in control populations, but the rate of increase in decay was the same in both groups when adults and children were included. Weaver concluded that fluoride at or around 1 ppm did not reduce dental caries. Stating "I think that the most important lesson to be learned from the North and South Shields investigation is that the caries-inhibitory property of fluorine seems to be of rather short duration." and ". . . there is in fact no very striking difference in the incidence of caries in the two towns." he advised that there was no case for water fluoridation.

The case for fluoride's delaying of the onset of childhood caries, was strengthened by figures published by the Ministry of Health in 1969. These showed that after eleven years of artificial fluoridation, fourteen-year-old children drinking fluoridated water had an average of 6.3 decayed teeth, compared with 7.2 in non-fluoridated areas, a difference of less than one tooth.

In 1972, Schatz proved that the apparent reduction of dental caries in fluoridated areas was an illusion. As the caries-causing effects of carbohydrate foods only damage teeth once they have erupted and they are in contact with those foods, teeth that erupt later are effectively younger than teeth which erupt earlier. In other words, the caries-causing bacteria have had less time to do their damage. And because of this shorter exposure, the teeth of fluoridated children understandably have less decay. While it can truthfully be said that fluoride is responsible for lower rates of decay seen in fluoridated children who are the same age as unfluoridated children, it is not because fluoride has any beneficial action on the decay. It merely puts it off for a while — comparing ages when dental caries rates were similar. In 1993 Schatz declared:

"The data clearly showed that fluoridation only delays the appearance of caries . . . Fluoridated children develop the same amount of tooth decay as their non-fluoridated counterparts over their lifetime. The only difference is that caries start developing approximately 1.2 years later.

"There is no economic benefit for such actions. Since fluoride does not reduce caries . . . both groups will therefore require the same amount of dental treatment. People in fluoridated areas therefore pay for the same amount of dental treatment plus the added cost of fluoridation." Table 3 demonstrates clearly this delay: differences between the numbers of decayed teeth in fluoridated and unfluoridated children becomes less as the children get older.

This flaw, which was not noticed when the very early research was done, invalidates many epidemiological surveys that purport to show less decay in fluoridated children than in non-fluoridated children of the same age, on which the whole case for fluoride is based.

Many doctors and dentists over the years have pointed to this apparent fault and have called for the numbers of erupted teeth to be counted in studies, and published. As long ago as 1960 Lord Douglas of Barloch referred to the possible delay in the eruption of teeth, and stated: "If this is so, it is a matter of grave concern for it indicates a profound physiological change." But even today, this point still has not been resolved. It is standard practice for dentists to note and record which teeth are decayed, filled or missing, whether they have been shed or extracted and those which have not yet erupted, for each of their patients. Therefore it is a very simple matter to determine, for each sex group, the average number of each type of tooth, and the total number of teeth, which have erupted at each age. Yet in official British experiments no count is made of the numbers of teeth erupted, or if it was, the data isn"t published. The fact that these data are important has been made many times in the dental literature. Despite this, the figures for erupted teeth aren"t included — or are they suppressed deliberately?

In 1997 a study carried out in Tanzania showed that the later in life enamel was completed, the higher was the severity of dental fluorosis .

WHO says so

The claim of "over a hundred studies . . ." appears to be backed by the WHO publication Environmental Health Criteria for Fluorine and Fluorides , which was published in 1984. The scientists who wrote this gave as their reference the data displayed in a poster by Drs J J Murray and A J Rugg-Gunn in 1979. This stated that "120 fluoridation studies from all continents showed a reduction in caries in the range of 50 to 75% for permanent teeth". Although the WHO document doesn"t say it, the poster's data obviously came from the same source as those in a table in a book listing 128 studies that Murray and Rugg-Gunn had published two years earlier.

In 1988, Philip Sutton investigated the scientific basis for the WHO's paper and published the results in Chemical and Engineering News. Here are his findings:

• There were no controls. A table of the studies gave the impression that fluoridated children were compared with children who had not had fluoride treatment. This is, of course, common medical practice — there is little point in showing a reduction of caries in children treated with fluoride, if untreated children have also had a similar reduction, and this is not taken into account. But Sutton found that all 128 studies listed had either no controls or inappropriate controls. That in itself, diminishes the authority of the studies" results.
• None of the studies allowed for bias. Assessment of the effects of fluoride depends on a visual examination of children's teeth. This calls for a subjective judgement by the examining dentists. If those dentists have already formed an opinion on the value of fluoride, and they know in advance which children have had fluoride and which haven"t, this can have an effect on their judgement, albeit an unconscious one, such that the extent of caries in the unfluoridated area is exaggerated. This is a well-known defect of all fluoridation trials. To obviate it, such trials should be conducted "blind": e.g. dentists should not know whether the children they are examining have or have not been treated with fluoride. None of these studies took steps to avoid such a bias.

With these defects, the value of these studies as a basis for population-wide intervention was already precarious. Sutton found, when he delved deeper, even more disturbing aspects:

• Forty-six of the listed studies were actually only twenty-three. Data on deciduous and permanent teeth were listed separately thus doubling the number.
• Two studies which included data from more than one town were listed as six studies.
• Seven case reports in different years from the same study were listed as fourteen studies.

• The most important claim made for fluoridation is that it decreases dental caries in the permanent teeth. Contrary to the statement in that WHO book, 20 studies listed did not present any data for those teeth.

• Sixteen were short reports in state dental newsletters and journals.
• Fourteen were short communications in newsletters and bulletins issued by state health departments.
• Eight were essentially progress reports.
• Three were personal communications.
• Two were anonymous.
• Four were original trials but they had been known to be faulty for 25 years.
• Three were obviously incapable of demonstrating that fluoridation is efficacious.
• And one did not refer to fluoridated water at all.

The last twenty-three
By now Sutton had whittled what had been an impressive list of 128 studies down by over eighty percent. But, even so, twenty-three studies, if valid, might be enough to back the claim that fluoridation decreases the prevalence of dental caries substantially. But these, like all the other studies, turned out to be just as suspect:

• Four could not be verified as they could not be obtained. None was even listed in the Index to Dental Literature or in Index Medicus.
• That left just 19 studies which came from a number of fluoridated countries. None of them showed in a scientifically-acceptable manner that fluoridation is efficacious.

Therefore, in what appears to have been comprehensive world-wide search, it seems that Murray and Rugg-Gunn were unable to locate a single study which demonstrated that fluoridation was effective at reducing or preventing dental caries. And the foundation on which the WHO document and countries' subsequent fluoridation programmes were built was as substantial as quicksand.

Sutton discovered these discrepancies merely by referring to Murray and Rugg-Gunn's table and reading their references. Why didn"t the WHO panel?

A dentist defects

The late Dr. John Colquhoun, was Chief Dental Officer of the Department of Health for Auckland, and President of the New Zealand Fluoridation Society and, of course, a fervent supporter of fluoride and fluoridation. However, he discovered a number of worrying signs which led him to question the advisability of fluoridation. As a result of what he discovered he came out against fluoridation. Dr Colquhoun explained why he had done so in a public lecture given in Fife, Scotland on 4 September 1996.

In Auckland, he had noticed a dramatic decline in decay rates which was not confined to the fluoridated areas. In both the fluoridated and unfluoridated parts of the city the declines were similar. It was suggested to him that this was due to the use of fluoride toothpaste by children living in the unfluoridated part of the city. But he knew that in the unfluoridated part, very few children used fluoride toothpaste, most had not received fluoride applications to their teeth and hardly any had been given fluoride tablets.

When he received the figures for Auckland, Dr Colquhoun says:

"To my horror, they showed that fewer fillings had been required in the unfluoridated part of Auckland than in the fluoridated part".

So he asked for the national figures for tooth decay rates of all 5-year-olds in New Zealand obtained from dental clinics throughout the country for the period 1930-1990, together with data on water fluoridation and fluoride toothpaste use.

At Figure 2 you can see what Dr Colquhoun saw after he had analysed the figures: there had been a decline in decay rates over the whole period, beginning well before fluorides started to be used.

When Dr Colquhoun received these figures, they came with a warning that they were not to be made public. Dr Colquhoun realised why, he says, when he examined them: "They showed that in most Health Districts the percentage of children who were free of tooth decay was greater in the unfluoridated parts of the district".

As part of his grooming for the post of Chairman of the national Fluoridation Promotion Committee, he was sent on a fact-finding world study tour. He found the sorts of evidence presented here.

When Dr Colquhoun came out against fluoridation it was a great and courageous step on his part. Men in far less public positions had been summarily dismissed and shunned by their peers for speaking out against fluoride.

When "facts" lie

Earlier I mentioned the comparison between naturally fluoridated Hartlepool and unfluoridated York. Throughout any country it is not difficult to find a variety of levels of tooth decay in both fluoridated and unfluoridated areas. The United Kingdom Dental Health League Table, published in November 1997 by the British Fluoridation Society lists 208 districts, their levels of dental caries in 5-year-olds and levels of fluoridation. Top of the list with 0.54 decayed, missing and filled teeth (DMFT) is fluoridated Bromsgrove & Redditch; bottom with 3.96 DMFT is North Manchester which is unfluoridated. If one picks a fluoridated area with a low level of tooth decay and an unfluoridated area with a high level, disregarding any other differences between them, it is not difficult to "prove" that fluoride prevents caries.

But there are several comparable districts, fluoridated and unfluoridated, where levels of carious teeth are the same. Gateshead and Liverpool are demographically quite similar and both have 1.85 carious teeth per child. But Gateshead is one-hundred percent fluoridated while Liverpool is unfluoridated.

So when comparing towns like Hartlepool and York, one has to look more closely at other possible confounding factors. Doing this we find that in the 1960s, when this study was conducted, the biggest employer in York was the sweets manufacturer, Rowntree's. Rowntree's employed a sizeable proportion of the city's population. Not only did it allow its workers to eat as much confectionary as they wished while they were at work, they were also allowed to collect all the bits left over at the end of the week to take home. Thus it is likely that their friends and relatives also had a higher intake of sweets than most. It is just as likely, therefore, that the reason York had a higher decay rate than Hartlepool was not a lack of fluoride in its water supply, but simply its greater intake of caries-causing sweets.

Other British studies were conducted which were not so contrived. They tell a different story. One major study conducted for the Ministry of Health measured tooth decay rates in 8- to 10-year-olds in five towns while, in another 9- to 14-year-olds" teeth were studied in Kilmarnock. Neither showed a significant beneficial effect from fluoride.

The World Health Organisation monitors decayed, missing and filled teeth regularly. Its figures at Table 4 provide no support for the claim that fluoridation of drinking water helps to preserve children's teeth.

The Republic of Ireland has been fluoridated for over 30 years but in terms of the numbers of decayed, missing and filled teeth, it ranks only sixth in Europe behind countries which are not fluoridated. And in terms of reductions in DMFT, which is where the benefits of fluoridation are claimed, Ireland drops to seventh place behind Norway and the next most fluoridated country, the UK, drops to sixth place.

Evidence mounts

British Columbia has the lowest rates of caries in Canada. Yet it is only eleven percent fluoridated compared with between forty and seventy percent in the rest of Canada. If that weren"t enough, the lowest rates of caries are found in the areas of British Columbia that are not fluoridated at all.

The largest study on fluoridation and tooth decay ever undertaken was performed by the USA National Institute of Dental Research. The subjects were 39,000 children aged five to seventeen living in eighty-four different areas. A third of the places were wholly fluoridated, a third were partially fluoridated, and a third were not fluoridated. There were no statistically significant differences in dental decay between them.

All Native American reservations are fluoridated. Yet children living there have much higher rates of dental decay than do children living in other U.S. communities.

A University of Arizona study in 1992 found that "the more fluoride a child drinks, the more cavities appear in the teeth."

Table 4: Comparison of Decayed, Missing And Filled Teeth (DMFT) in 12-year-olds in European Countries (Source: World Health Organisation, Noncommunicable Disease Division)

The WHO reported a decline in dental decay in Western Europe and say that Europe's decay rates are at least equal to and sometimes better than rates in the USA. Yet, while the USA is largely fluoridated, Europe is hardly fluoridated at all.

Fluoride damages teeth

Much research from many parts of the world has suggested that, far from protecting teeth, fluoride actually damages them. One of the largest studies into fluoride levels and dental caries ever carried out comes from Japan. In this study, researchers at Tokyo Medical and Dental University examined the teeth of 20,000 students and showed clearly that they had been harmed by fluoride. The researchers compared students who came from areas with more than 0.4 parts per million fluoride in the drinking water with those whose water contained less than 0.4 ppm. Their results showed clearly that there was significantly more decay in the areas that had the higher levels of fluoride. Note that the 0.4 ppm that was harming teeth is less than half the "optimal" level. Similarly another study, conducted in Ottawa, Kansas, to assess the effects of adding fluoride to the town's water found that fluoridation was a disaster: in the first three years of drinking fluoridated water, the numbers of DMFT in 5- to 6-year-old children more than doubled, while the numbers free from decay nearly halved.

That fluorides have not been shown to benefit teeth should not come as a surprise to the dental profession. As long ago as 1940, it was suggested that seventy percent of the caries in children was in the form of pits and fissures. Recent reports indicate that today, eighty-three per cent of all caries in North American children is of this type. And there is no reason to suppose that children in other Western countries are any different. Pit and fissure cavities are prevented with sealants, they aren"t preventable with fluoride.

Fluoridation is stopped — and teeth get better

The town of Kuopio, in eastern Finland, was fluoridated in 1959. But owing to strong opposition by different civic groups, water fluoridation was stopped at the end of 1992. It was a perfect opportunity to examine the consequences of this discontinuation on dental health. If the theory that fluoride prevented caries was correct, then discontinuing fluoridation should lead to increases in caries. To test this, in 1992 and 1995, independent random samples of all children aged 6, 9, 12 and 15 years were drawn from Kuopio with a nearby low-fluoride town, Jyvaskyla, whose distribution of demographic and socio-economic characteristics was fairly similar to Kuopio's acting as the control group. Dental caries was registered clinically and radiographically by the same two calibrated dentists in both towns.

In 1992 the mean DMFS values were lower in the fluoridated town for the two older age groups but no meaningful differences for the two younger age groups. In 1995, the only difference with possible clinical significance was an eighteen percent reduction found in the 15-year-olds in fluoridated Kuopio. In that year, a decline in caries was seen in the two older age groups in the non-fluoridated town.

In spite of water fluoridation having ceased, there was no indication of any increasing trend of caries in Kuopio.

The researchers considered that, perhaps, caries were prevented by better or more aggressive dental care. But in fact the numbers of fluoride varnish and sealant applications had decreased sharply in both towns. The researchers conclude that there was no evidence that the cessation of water fluoridation was having a detrimental effect and the decline of caries in the two towns had little to do with professional preventive measures performed in dental clinics.

Dentists modify their claims

As the years have passed, dentists and others have made progressively more modest claims for fluoride. The American Dental Association claims today that fluoride reduces caries by between eighteen and twenty-five percent while just over a decade ago, they were claiming forty to sixty percent reductions. Other former supporters are beginning to question the need for water fluoridation. In 1990 a report from the National Institute for Dental Research in the USA stated that "it is likely that if caries in children remain at low levels or decline further, the necessity of continuing the current variety and extent of fluoride-based prevention programs will be questioned."

Conclusion

Given the strength of the evidence presented, the case for the fluoridation of tap water to prevent dental decay fails miserably. Nevertheless on both sides of the Atlantic, proponents, seemingly oblivious to the evidence that fluoride does more harm than good, are currently trying to get still more areas fluoridated. In 1992, when sixty percent of the US population was fluoridated, and based on what they say is "past progress and continuing evidence of effectiveness and safety of this public health measure" the American Public Health Service set a goal of having seventy-five percent of the population drinking fluoridated water by the year 2000. And now, as I write this in 2000, the government-funded British Fluoridation Society is actively lobbying for a change in the law here to compel water companies to fluoridate tap water when Health Authorities demand it.

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Last updated 12 April 2006