An Overwhelming Number of Scientific Studies Conclude That Cavity Levels are Falling Worldwide ... Even In Countries Which Don't Fluoridate Water → Washingtons Blog
An Overwhelming Number of Scientific Studies Conclude That Cavity Levels are Falling Worldwide ... Even In Countries Which Don't Fluoridate Water - Washingtons Blog

Tuesday, January 11, 2011

An Overwhelming Number of Scientific Studies Conclude That Cavity Levels are Falling Worldwide ... Even In Countries Which Don't Fluoridate Water

Everyone agrees that the number of cavities have plummeted in the U.S. over the last couple of decades, after water fluoridation was introduced (that is why health officials call water fluoridation "one of the ten greatest public health accomplishments of the last century").

That proves that water fluoridation fights cavities, right?

It would, of course, if the cavity levels have not also plummeted in countries which do not fluoridate their water.

Let's take a look at the scientific literature to get an unvarnished picture on the trends.

Cavity Levels Have Only Plummeted In the U.S. And Other Countries Which Fluoridate Water, Right?

Science magazine noted in 1982:
The decline in caries [the scientific term for "cavities"] prevalence in communities without fluoridated water in various countries is well documented. The cause or causes are, at this time, a matter of speculation.
The Journal of Public Health Dentistry noted in 1985:

Even the most cursory review of the dental literature since 1978 reveals a wealth of data documenting a secular, or long term, generalized decline in dental caries throughout the Western, industrialized world. Reports indicate that this decline has occurred in both fluoridated and fluoride-deficient areas, and in the presence and absence of organized preventive programs.

The prestigious science journal Nature noted in 1986:

[D]uring the period 1979-81, especially in western Europe where there is little fluoridation, a number of dental examinations were made and compared with surveys carried out a decade or so before. It soon became clear that large reductions in caries had been occurring in unfluoridated areas. The magnitudes of these reductions are generally comparable with those observed in fluoridated areas over similar periods of time

The Journal of the American Dental Association noted in 1988:

The current reported decline in caries tooth decay in the US and other Western industrialized countries has been observed in both fluoridated and nonfluoridated communities, with percentage reductions in each community apparently about the same

The Boston Globe reported in 1989:

The debate over fluoridating public water supplies, a measure long credited with producing a dramatic drop in tooth decay in the United States, is being rekindled by new studies suggesting the decline may have more to do with other causes, including other sources of fluoride.

The most exhaustive study ever conducted on the dental health of American children, conducted in 1986-87, has confirmed the great decline in cavities in the last 10 years, but it found much less difference than expected between areas with and without fluoridated water.

The Journal of Public Health Dentistry noted in 1991:

During the past 40 years dental caries has been declining in the US, as well as in most other developed nations of the world... The decline in dental caries has occurred both in fluoride and in fluoride-deficient communities, lending further credence to the notion that modes other than water fluoridation, especially dentrifices, have made a major contribution.

The Critical Review of Oral Biology and Medicine noted in 2002:

It is remarkable, however, that the dramatic decline in dental caries which we have witnessed in many different parts of the world (for reviews, see Glass, 1982; Fejerskov and Baelum, 1998) has occurred without the dental profession being fully able to explain the relative role of fluoride in this intriguing process. It is a common belief that the wide distribution of fluoride from toothpastes may be a major explanation (Bratthall et al., 1996), but serious attempts to assess the role of fluoridated toothpastes have been able to attribute, at best, about 40-50% of the caries reduction to these fluoride products (Marthaler, 1990; Scheie, 1992). This is not surprising, if one takes into account the fact that dental caries is not the result of fluoride deficiency.

The International Society of Fluoride Research noted in 2005:

Graphs of tooth decay trends for 12 year olds in 24 countries, prepared using the most recent World Health Organization data, show that the decline in dental decay in recent decades has been comparable in 16 nonfluoridated countries and 8 fluoridated countries which met the inclusion criteria of having (i) a mean annual per capita income in the year 2000 of US$10,000 or more, (ii) a population in the year 2000 of greater than 3 million, and (iii) suitable WHO caries data available. The WHO data do not support fluoridation as being a reason for the decline in dental decay in 12 year olds that has been occurring in recent decades.

The British Medical Journal noted in a 2007 paper:

Although the prevalence of caries [i.e. cavities] varies between countries, levels everywhere have fallen greatly in the past three decades, and national rates of caries are now universally low. This trend has occurred regardless of the concentration of fluoride in water or the use of fluoridated salt, and it probably reflects use of fluoridated toothpastes and other factors, including perhaps aspects of nutrition.

Clinical Oral Investigations noted in 2007:

In most European countries, where community water fluoridation has never been adopted, a substantial decline in caries prevalence has been reported in the last decades, with reductions in lifetime caries experience exceeding 75%.
And the Globe and Mail wrote last year:
There has also been a worldwide reduction in cavity rates, regardless of whether countries use the chemical, suggesting factors other than adding it to water supplies are at work.
And data published by the World Health Organization shows this dramatic plunge in cavities in virtually all countries (chart courtesy of Chris Neueth, Fluoride Action Network):

When Fluoridation Is Stopped, Cavities Do Not Increase

Further evidence of the ineffectiveness of water fluoridation is that the scientific literature shows that - when fluoridation of water supplies is stopped - cavities do not increase (but may in some cases actually decrease). See this, this, this, this, this and this.

Prominent Pro-Water Fluoridation Experts Have Changed Their Mind

Several prominent leaders of the pro-water fluoridation movement have recently admitted publicly that they were wrong, including:

  • John Colquhoun, DDS, Principal Dental Officer for Auckland, New Zealand and chair of that country's Fluoridation Promotion Committee, reviewed New Zealand's dental statistics in an effort to convince skeptics that fluoridation was beneficial and found that tooth decay rates were the same in fluoridated and nonfluoridated places, which prompted him to re-examine the classic fluoridation studies. He withdrew his support for it in "Why I Changed my Mind About Water Fluoridation" (Perspectives in Biology and Medicine 1997;41:29—44).
  • Richard G. Foulkes, MD, a health care administrator and former assistant professor in the Department of Health Care and Epidemiology at the University of British Columbia also switched from pro to anti-water fluoridation after studying the issue.

And see this testimony to Congress by PhD chemist William Hirzy, who - at the time of the hearing - was Senior Vice-President of the union representing EPA toxicologists, biologists, chemists, engineer and lawyers:

If It's Not Fluoride in Water, Why Are Cavities Decreasing?

If it's not water fluoridation, then what is causing cavity levels to dropping worldwide?

No one knows, but scientists have proposed different explanations. See, for example, this:
The causes for the changed caries trend were seen on the one hand in improvements in attitudes towards oral health behaviour and, on the other hand, to the broader availability and application of preventive measures [including fluoride toothpaste].
And this:
Dr. Limeback said factors that might be preventing caries include increased exposure to vitamin D, better oral hygiene, less sugar consumption, and even antibiotics.
And this:
Factors other than fluoride, such as food additives and antibiotics, may have contributed.
And this:
The caries decline is probably caused by a broader availability of fluorides [in toothpaste], a high level of individual dental curative and preventive care (fissure sealings) and by changed oral health behaviour and nutritional habits. Reference is made to a possible tangent between a high level of antibiotics consumption and the virulence of oral pathogenic streptococci.
Why Should We Care?

Who cares if water fluoridation isn't effective in preventing cavities?

Well, new evidence demonstrates that fluoride is extremely toxic: it can cause cancer, damage liver, kidneys, endocrine systems, and even lower IQ.

Moreover, several scientific studies have found that the type of fluoride added to most water supplies (mainly obtained as an industrial byproduct from phosphate fertilizer plants) is more toxic than the type added to toothpaste, and may contain lead, arsenic and other heavy metals.

So if water fluoridation may be doing a lot of harm but no good in fighting cavities, isn't that contrary to good science?

Afterword: I am NOT Against Fluoride Toothpaste

While I am against adding fluoride to water, I am not against people using fluoridated toothpaste if they wish.

Topical application of fluoride - with toothpastes, gels or rinses - gets more fluoride to the teeth and less to the body as a whole.

The Centers for Disease Control noted in a 1999 report:

Laboratory and epidemiologic research suggests that fluoride prevents dental caries predominately after eruption of the tooth into the mouth, and its actions primarily are topical for both adults and children.

Dr. Arvid Carlsson - Nobel prize winner in medicine in 2000 - points out (in a brief, must-watch video) that water fluoridation goes against all principles of pharmacology, because fluoride works topically on teeth, not by oral ingestion.

A petition signed by Dr. Carlsson, as well as three members of the prestigious 2006 National Research Council (NRC) panel that reported on fluoride's toxicology, two officers in the Union representing professionals at EPA headquarters, the President of the International Society of Doctors for the Environment, and hundreds of medical, dental, academic, scientific and environmental professionals, worldwide, states:

The CDC [conceded], in 1999 and 2001, that the predominant benefit of fluoride in reducing tooth decay is TOPICAL and not SYSTEMIC. To the extent fluoride works to reduce tooth decay, it works from the outside of the tooth, not from inside the body. It makes no sense to drink it and expose the rest of the body to the long term risks of fluoride ingestion when fluoridated toothpaste is readily available.

Fluoride’s topical mechanism probably explains the fact that, since the 1980s, there have been many research reports indicating little difference in tooth decay between fluoridated and non-fluoridated communities ....

The Globe and mail noted last year:

When fluoridation started 60 years ago, doctors thought swallowing the chemical was beneficial by strengthening teeth from the inside out. Dr. Limeback said more recent research shows that if there is a benefit, it is from the topical application of fluoride to the surface of teeth, which suggests that brushing with a toothpaste is more effective than drinking water containing the chemical.

Professor Aubrey Sheiham - Emeritus Professor of Dental Public Health at the University College London - writes:
Fluoride, particularly in toothpastes, is a very important preventive agent against dental caries. Toothbrushing without fluorides has little effect on caries. As additional fluoride to that currently available in toothpaste does not appear to be benefiting the teeth of the majority of people, the main strategy to further reduce the levels of caries, is reducing the frequency of sugars intakes in the diet.
Time Magazine notes:
Because toothpaste is designed to be spit out, it's a more efficient way to get the decay-fighting ingredient where it is needed and nowhere else. Even some dentists, who see firsthand the benefits of fluoridation, wonder whether people who get fluoride from toothpaste should get it in their drinking water as well.
ABC News' medical and scientific journalist, Nicholas Regush, writes
The fluoride is in your toothpaste to fight cavities. When it comes into direct contact with teeth, fluoride appears to help. The much bigger questions are whether we need to fluoridate the entire water supply to achieve this and whether water fluoridation, an indirect method to fight cavities, actually works.


What is amazing, however, is that public health policy in this country has allowed water fluoridation to continue in the absence of solid scientific evidence that its benefit is greater than its risk.

When you commit to putting a powerful chemical into the water supply, you’d better have the best of evidence that it is both safe and effective. The required level of evidence is just not there.

Similarly, the Environmental Working Group - a science-based group which has conducted research into and helped publicize many toxic chemical dangers, such as Bisphenol A and drinking water pollution - says:
The Environmental Working Group supports the use of fluoride in toothpaste, where there is strong evidence of its effectiveness. But EWG’s analysis concludes that fluoridation of public water supplies should end, because the risks outweigh possible benefits, especially for infants and young children, because they consume more water than adults relative to their size.
And the Sierra Club notes:
The Sierra Club understands the historic reason that fluoridation of public water supplies has been promoted .... There are now, however, valid concerns regarding the potential adverse impact of fluoridation on the environment, wildlife, and human health.

Therefore, the Sierra Club believes that communities should have the option to reject mandatory fluoridation of their water supplies.

To protect sensitive populations, and because safer strategies and methods for preventing tooth decay are now available, we recommend that these safer alternatives be made available and promoted.


  1. Those of us who etch teeth to bond dental filling materials to them can observe that a tooth with slight fluorosis takes longer to etch. This appears to indicate resistance to the acid used for etching.

    Fluorosis is an "in the tooth" phenomenon that is not created by topical application of fluoride. Therefore, there certainly appears to be a benefit to the proper amount of fluoride being present in the bloodstream during the formation and growth of teeth. A chemically more stable structure is likely to occur.

    Next, there is a phenomenon not usually discussed: secretion of fluoride via salivary glands. I personally discussed this with a leading researcher at the National Institute of Dental Research in the late 80's. He admitted that to be a gray area: hardly anything was known about that.

    Last, bone incorporates fluoride just like teeth. Bone undergoes constant turn-over, being dissolved and re-built constantly. Fluoride must be released in the process, to some degree. That provides a kind of "reservoir" of fluoride in the body. What's known as the "metabolic fate" of that fluoride was not known at the time. Perhaps it has been studied since then, along with a wide variety of related issues.

    One of my dental school classmates, Dr. Gary Whitford, has published extensively on topics related to fluoride metabolism. Sad to say I have not kept up with his work.

    Final point: those who say that the effect of fluoride is strictly topical are mistaken. Studies of the structure of teeth show that fluoride is incorporated throughout the structure, not just on the surface. I can't imagine anyone maintaining a contrary view, or how they could support it with real science.

  2. Regardless of the potential benefits of fluoride in the body, it should not be public policy to put the chemical into our world's drinking water.

    Why not add a multi-vitamin while your at it. Or better yet, some anti-depressants. Then we can all be happy and healthy under big brothers orders.

  3. To Dr.

    I am a dental student and have worked for some time now in the clinic with restorations. I can't recall that drilling or etching a fluorosed tooth is harder than not fluorosed one, which you claim is a good sign and something works as a pros for Water Fluoridation. We, DR, were taught at school that fluorosis, if happens, can lead to brittleness of the tooth hard structures, which in turns, lead to the exact opposite end of which pro-fluorosis talk about. Brittleness means that the work of fluoridation goes in vain. Plus why should we fluoridate with all these caries-plummeting data between communities with F and others with no other data supporting its(fluoride) effects on the brain cells and its cancer-causing effects. I mean isn't that enough to at least stop doing it!


  4. Another great article George. The only thing I would quibble with is your first point:

    "It would, of course, if the cavity levels have not also plummeted in countries which do not fluoridate their water."

    This is not necessarily true. Even in those fluoridated areas where cavity levels had dropped you would still have to prove that it was the fluoride and not some other factor(s) eg economic that had caused the drop in cavities. You would also have to analyze the integrity/accuracy of the reporting in those areas as well just as you would in the unfluoridated areas.

    The other concern of course with water fluoridation is the ethical. It is simply wrong to drug people without their consent even if the drug (allegedly) benefits them.

    But as I say another great article George and anyone that spends two minutes looking into fluoride knows that even if it did work as billed the health risks far outweigh any purported dental benefits. This dastardly practice will go down in history as one of the greatest, most injurious, frauds and most shameful episodes in Western medicine.


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