Fluoridation – it does reduce tooth decay

In the current fluoridation debate anti-fluoridation activists will often claim fluoridation of public water supplies actually doesn’t reduce tooth decay. This conflicts directly with the advice of our health authorities – so what is the truth?

The claim

Again I will directly consider the claim of the Fluoridation Action Network of NZ (FAANZ). It’s summarised in the first objection to fluoridation (1. New science proves there is no benefit from swallowing fluoride ):

There are numerous modern studies to show that there is no difference in dental decay rates between fluoridated and non-fluoridated areas. The most recent, large-scale one was conducted in Australia (Armfield & Spencer, 2004 Community Dental Oral Epidemiology. 32:283-96).

When you observe the statistics of the world they clearly show tooth decay has declined in both fluoridated and non-fluoridated areas alike. This is a trend that is demonstrated when viewing the statistics across the States in America and in the smaller counties. See the charts and findings by Dr. Bill Osmunson in the above video by Professional Perspectives.

In New Zealand there have been two recent studies that showed there was no difference in dental decay for permanent teeth. One was the Southland Study in 2005 and the other was the Auckland study in 2008. These, among many other studies, have proven water fluoridation to be ineffective.

(This objection goes on to discuss topical vs systemic intake of F which I won’t discuss here)

But, health authorities in New Zealand disagree – and they have the data to support their case. So how credible is the FANNZ claim?

The citation.

Again, another citation, unlinked, so I had to go to the trouble of hunting it down to read what it actually does say – which turns out to be the exact opposite of FANNZ claim! Same problems I met when I looked at their claim about toxic elements in fluoridating agents (see ).

The Australian study (Armfield& Spencer, 2004 Community Dental Oral Epidemiology. 32:283-96) investigated concerns about the high use of bottled and rainwater. Several social, economic and dietary factors were considered but the major significant effect was that of fluoride. Children consuming tank and bottled water had much higher carries than those consuming water from fluoridated public water supplies. This was found for deciduous teeth, but not for permanent teeth and the authors speculated on the dietary and other reasons for this. They concluded:

“This study demonstrates the continued community effectiveness of water fluoridation and provides support for the extension of this important oral health intervention to populations currently without access to fluoridated water.”

The authors considered lack of fluoride is an important problem for tank water use saying:

“Efforts could be directed at either reducing the use of tank water for domestic drinking water consumption or further encouraging the appropriate use of fluoride to compensate for the lack of fluoride in the drinking water.”

About bottled water they say:

“consumers currently have little choice in Australia and the imminent introduction of fluoride-containing bottled water does not look likely.”


“It is also time that bottled water manufacturers in Australia began marketing fluoridated water. In the US more than 20 companies produce water with optimum fluoride concentrations.”

They finish their paper with this:

“Bottled water is promoted as a healthy, chemical-free alternative. There is a need for bottled water manufacturers to take a stand on the issue of the benefits of appropriately fluoridated water and provide consumers with choice.”

So another example of FANNZ using a citation inappropriately – to support a claim the exact opposite to the study’s results.

The New Zealand data.

The Ministry of Health (MOH) keeps records on the oral health of New Zealand children – and anyone can download that data from their website. There is data for age 5 and year 8 children over the time period 1990 to 2011. I’ll have a detailed look at the data for 2002 – 2011 (earlier data doesn’t include the ethnic breakdown which is very relevant). But first a few comments about the way many of the anti-fluoridation activists are cherry picking this and similar data to support their arguments.

Recently I received two specific claims made about this data:

  1. The oral health of Christchurch people is better than for New Zeland as a whole. The don’t have access to fluoridated water therefore this proves fluoridation doesn’t work.
  2. In 2011 the mean number of decayed, missing and filled teeth in 5 year old Waikato children was greater for children drinking fluoridated water than for those drinking unfluoridated water. This proves fluoridation doesn’t work.

In both claims data was carefully selected to “prove” fluoridation doesn’t work. One can’t directly compare Christchurch data with that for the whole of New Zealand as that ignores the influence of ethnic, social and other factors. And selection of one small piece (Waikato in 2011) of the total picture cannot give you any idea of that total picture. The data includes all sorts of variation over time and region and these cherry-pickers are make cynical use of this.

I have summarised the MOH data in this table as the changes for the percentage of carries free teeth, and mdmf – the mean number decayed, missing and filled teeth per child per year. The data are for 2 age groups and are averages, over the period 2002 to 2011, of annual data . The totals and the separate data for Maori give some idea of differences which are probably largely a result of the well established social and economic disadvantage of Maori.

Effect of fluoridation of % carries free and mdmf

Year 8

Total Maori
Carries free (%) 8.86 10.42
MDMF* -0.48 -0.81

5 years

Total Maori
Carries free (%) 8.05 12.46
MDMF* -0.63 -1.38

*MDMF = Mean decayed, missing and filled teeth

I think that shows fluoridation is associated with a clear increase in numbers of carries free teeth, and a clear decrease in the mean decayed, missing and filled teeth.

So much for FANN’s claim “that there is no difference in dental decay rates between fluoridated and non-fluoridated areas.”

The figures below show the data graphically to enable readers to get a better understanding.

First a comparison of average annual % carries free teeth and mdmf in the period 2002 -2011 for the two age groups.

% carries free


Mean decayed, missing and filled teeth


Plots of the data below give and idea of variability and trends. They also show the influence of social and economic deprivation is long-term.

% carries free




A comment in trends

Some anti-fluoridationists are making an issue of the apparent improvement in oral health for people consuming unfluoridated as well as fluoridated water. For example, the claim above asserts:

“When you observe the statistics of the world they clearly show tooth decay has declined in both fluoridated and non-fluoridated areas alike.”

Perhaps they think that this somehow covers up the fact that despite the trends oral health it is still better for the fluoridated groups.

Mind you, another reason is that many of the statistics they refer to are presented only graphically. For example this figure from Fluoride Alert (an anti-fluoridation group) actually does not correspond to the data it refers to.


It seems the figure was constructed using only 2 data points of each line – 1 very old and 1 recent. This means that all sorts of factors, (such as changes in criteria and attitude of dentists towards saving teeth) could be involved – quite apart from fluoridation.

The data I have plotted above the New Zealand in the period 2002 – 2011 does not show the declines that the anti-fluoridationists claim.

Another example of cherry-picking to mislead.

See also:

Getting a grip on the science behind claims about fluoridation
Is fluoride an essential dietary mineral?
Fluoridation – are we dumping toxic metals into our water supplies?
Tactics and common arguments of the anti-fluoridationists
Hamilton City Council reverses referendum fluoridation decision
Scientists, political activism and the scientific ethos

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63 responses to “Fluoridation – it does reduce tooth decay

  1. Ken, can you explain the rise and rise in % carries free in unfluoridated children , both total and maori, over the past decade?

    I note you have not only used averages for DMFT but averaged them over a whole decade. In another blog you claimed using averages was dihonest… how bizarre that you resort to that now.

    You bag the trend graph as coming from an anti-fluoride group, and make no mention that and even more compelling one was published by the British Medical Journal and the co-author was no less than the person who set up the Evidence-Based Medicine Cochrane Reviews library. This graph has also been published by the European Commissions scientific committee in their review of fluoridation.

    Click to access Adding_fluoride_to_water_supplies.PDF

    Click to access fluoridation.pdf

    Apart from the time differences, your own graphs show similar declines in both fluoridated and none-fluoridated areas… if you went back to the 1990’s data you would note similar trends.

    In other words, the declines in decay in non fluoridated and fluoridated childrens teeth has been occurring for two decades…

    If you did trend lines for your graphs you’d see the same trends… if you plotted data for the past 3 decades the trend lines would be similar to those published in the BMJ and by the European Commission.

    When you look at your own data it clearly shows “When you observe the statistics of the world they clearly show tooth decay has declined in both fluoridated and non-fluoridated areas alike.”

    Presenting scientific evidence which shows such long term trends is not being anti-fluoride, as you claim, it is actually being scientific.

    Park your own beliefs at the door, and let the evidence do the talking…

    I challenge you to repost your graphs with computer generated trend lines… and do the same for total fluoridated and unflouridated % carries free and DMFT for the entire database.

    Then we can all see the evidence and judge for ourselves.


  2. Ron,

    1: All biological data has natural variation – surely you can think of some of the factors involved

    2: My criticism of your use of the total data was because by itself it does not show the important effects of social and economic deprivation. That is why I have included data for Maori – and why I chose to go back only as far as 2002

    3: It doesn’t matter who produces the graphics – to take one point back in 1970s and another in 2010 gives a very misleading picture of the trend. You can check that simply by plotting the data for all years yourself

    4: Yes if I went back to 1970 for totals in NZ the graph would show a rapid decline for both groups followed by a relatively steady plot – not a straight line decline. I suspect this would largely be because of changes in dental practices

    5: I am not interested in going back beyond 2002, because the social, economic and ethnic effects are ignored

    6: Nor am I interested in pulling out slopes over time from the data – the key thing is the difference between fluoridated and unfluoridated. Surely that difference is clear, and generally larger than you often suggest.

    By the way, Ron, thanks for providing me with examples of cherry-picked data.


  3. The problem is, Ron, that I distinctly remember you cherry-picking data from the MOH yourself. You could have presented some form of analysis as Ken has done, but instead, you chose to fling isolated figures at us as if they proved your assertions.

    Now, personally, I think Ken’s treatment of the data looks solid. Additionally, I have access to the data myself, so I can check his presented averages against overall trends. Of course, the graphs provided would seem to cover that.

    Plainly, you have plenty of time at your disposal. Certainly more than I do. I suggest that if you want an analysis of the data going back over the past 30 years, you get cracking and do it yourself, rather than complaining about Ken’s work.


  4. RonL, your research methodology has led you to conclude (and admit) that the conclusions, shared by almost all public health authorities on the planet, are flawed.

    So another question for you.

    Does that outcome give you cause to question your own methodology in evaluating the issue over that used by every mainstream science and public health organisation in the world?


  5. Actually, another question Ron ignores is the reliability if the anti-fluoridationist claims. This is the second time I have found the citation to be completely false. The papers cited say the exact opposite of what FANNZ claims..

    It’s usually called a lie.


  6. Ken, it makes you wonder if HCC did any fact checking of the submissions presented to them.
    I suspect they did exactly nil.


  7. I haven’t read FANNZ claims so I can’t comment. I am not anti fluoride… I am challenging the wild claims of effectiveness and the claims that these so-called benefits are so dramatic that they warrant ramming fluoridated water down every ones throats. As Gluckman says, that’s a values decision, not a science one.

    Ken, it’s good to see someone promoting mandatory fluoridation final engaging the data (that I brought to your attention) lets analyse the graphs you have provided. Let’s start with the first one for % carries.

    Do you agree that in 2002 for 5 year olds there was an ~12% difference and that had gradually declined due primarily to improved teeth in non-fluoridated by 2011 with essentially zero difference?

    If so, what evidence do you have that fluoridation of water supply in 2011 provided any benefits to 5 year olds?


  8. Ken, you say, “One can’t directly compare Christchurch data with that for the whole of New Zealand as that ignores the influence of ethnic, social and other factors. And selection of one small piece (Waikato in 2011) of the total picture cannot give you any idea of that total picture. The data includes all sorts of variation over time and region and these cherry-pickers are make cynical use of this.”

    Fascinating as the difference between Christchurch and Wellington was used by the Waikato DHB in their presentations.


    It seems there are two sets of rules at play here.


  9. 1: Ron, I think an objective person should be able to make some sort of judgement of the protagonists in this debate. What I am finding is that where they specifically cite a reference, and I check it out, they have completely misrepresented the findings.

    I showed that over their claim of toxic elements in the HFSA, and now over their claim that the Australian paper did not show an effect if F, when it clearly did. I suspect, strongly, that I am going to find it in other cases that I check.

    Now, you might ignore that, but I am concerned that when people make claims about the science, to the extent of using citations even, they should at least be truthful. The sad thing is that only a scientifically trained person with the time can actually check out and expose such lies. The Hamilton CIty Council obviously couldn’t.

    In future wouldn’t it be sensible for such submissions to be scrutinised by scientific experts and the submitter asked to explain such deficiencies?

    2: Taking the whole data set as a whole, Ron, do you agree that it is consistent with quite a large increase in carries free mouths and decrease in decay, fillings and missing teeth? Consistent with our understanding of the chemistry of F in bioapatites and other research on fluoridation? Do you also agree that the oral health if the disadvantaged groups in society is worse that on the average and that they get the biggest benefit from fluoridation?

    That is the overall picture – it does support the effectiveness of fluoridation improving oral health.

    3: Yes, there appears to be some convergence for some groups recently but I suspect whereas a statistical analysis would show a very high level of significance of the F effect for the overall set, the variation may be too great to make much of a story about your cherry-picked region and data. It’s a bit like the straw clutching that climate change deniers are in to at the moment because the last 15 years surface air temperatures don’t show a trend significantly different to zero. Many of them are announcing an impending ice age as a result.

    Now, Ron, are you confident enough about your cherry-picked section to announce that the previously observed effect of fluoridation no longer exists?

    Personally I would see this as more likely explained by some sort of social factor. For example, in the Australian study they found that single parent families drank more public water. But I am only speculating and obviously this is a thing health authorities will be able to lookout for in future. Unfortunately I don’t think their database really includes much in the way of social and dietary factors which could enable further digging into likely factors.

    4: I agree that Drumble and Aitkin are also cherry picking by comparing single cities and towns – they do this in several slides. While that may have some illustrative use it would be bad science to claim it as in any way a proof. A statistical analysis of the MOH data would provide the convincing “proof” as I am sure the significance would be very convincing.

    I don’t know how they described the specific slides. If it had been accompanies by the overall analysis and then those slides used as illustrations that would be OK. They just don’t provide good “proof.”

    4: No there are not 2 sets of rules. I am quite happy to criticise those slides in the same manner I have criticised your cherry picking. But you are rather pathetic, and desperate, to attempt to justify your cherry picking by pointing out others have done similar things. Cherry picking to support a bias is bad science whoever does it. Even if it is human.

    Hey, perhaps you should check out their citations and see if they have done anything as blatantly dishonest as the anti-fluoridationists.


  10. Ken, in your blog your quote refers to a video. Here it is.

    If nothing else, watch 8:30 to 9:32… Several speakers make comment beginning with Sir Ian Chalmers, the God Father of modern Evidence-Based Medicine. Using the WHO data he shows plots trends for a raft of countries by decade (not just two points). He said he was pro-fluoridation by default… that would have been my position until the Hamilton debate. He said the evidence floored him… when presented with anonymised trends, no one could differentiate fluoridated countries from non-fluoridated ones.


  11. Ken, you ask, “Taking the whole data set as a whole, Ron, do you agree that it is consistent with quite a large increase in carries free mouths and decrease in decay, fillings and missing teeth?”

    Absolutely it does… for BOTh fluoridated areas AND non-fluoridated areas. I’ve plotted all MOH data in the 1990’s for each area given. The over whelming pattern is quite a large increase in carries free mouths and decrease in decay, fillings and missing teeth for all areas in BOTH fluoridated AND non-fluoridated areas?

    I haven’t gone through and combined the data from the naughties… you are ahead of me there, but looking at your graphs the same pattern emerges.

    Have a look at totals minus maori and work out % caries free and DMFT and plot the results for fluoridated and non-fluoridated. Maybe you could post them for us all to see.


  12. Another issue is that all of the caries are obviously in the non-caries free children… divide the number of DMFT by the number who have DMFT and plot those… more revelations.


  13. Ron, considering how deeply unhappy you are about Ken’s work, I suggest you produce graphs of the data yourself, rather than demanding he cater to your whims. That way, you can display trends over whatever time period, in whatever detail, your little heart desires.

    I should note, however, that your goal (as I understand it) is not to demonstrate that dental health has improved all round, but that the gap between fluoridated and non-fluoridated populations has closed, all other things being equal.

    One of the most basic means of beginning to correct for those ‘other things’ is to use data for fluoridated and non-fluoridated populations within the same country. This is one reason I am deeply unimpressed by your periodic waving of international comparison graphs in front of us, whichever figures you might find to express surprise over them.

    Now, obviously, a large part of your argument is that these other factors have improved, leading to a decrease in the efficacy of fluoride. However, in order to demonstrate this, the other factors have to improve more or less uniformly across the populations you’re comparing. You do not, for instance, want substantial differences in wealth or public health programs clouding the issue if you can help it, yet this is all but a certainty when comparing different countries.


  14. An excellent article, well researched. End of the day, a council going against a public referendum is still outstandingly arrogant and morally questionable.


  15. Ron, you continue to divert the issue. What I have shown here is that the data is consistent with what we know of the chemistry of F in bioapatites and supports public water fluoridation as a health measure. I have also shown that FANNZ lied with their use of a citation – again!

    Now, if you wish to concentrate on the question of improving oral health apart from fluoridation (your claim that data shows that both groups have improving oral health – as well as the clear difference betwen the groups) go ahead and do so.

    It’s a seperate issue but may be interesting. Maybe you have discovered other factors besides the known ones which will be useful to health professionals. Then maybe not.

    However, can I suggest that the comments section of a blog is not the place for that. Why don’t you analyse the data, discuss the reasons and consider possible mechanisms and hypotheses for health improvements besides fluoridation (as well as fluoridation) – then post an article on your nown blog. We can then judge how well your arguments are supported and point out any flaws we see.


  16. Pingback: OP: Fluoridation – it does reduce tooth decay - The Standard

  17. Chris said, “I should note, however, that your goal (as I understand it) is not to demonstrate that dental health has improved all round, but that the gap between fluoridated and non-fluoridated populations has closed, all other things being equal.”

    Chris, I wouldn’t call this a goal of mine,,, but it certainly is factual as the data Ken has posted on here clearly shows.


  18. Ken, I note you have ignored the comments on the 5yo caries free graph… are you denying that the health of unfluoridated teeth has been improving at a faster rate than fluoridated and is now essentially the same?

    This points to factors other than drinking fluoridated water as being the cause of the improved oral health.


  19. Ron, are you suggesting the chemistry of bioapatites has suddenly changed? Or what?

    As I said if your have ideas on the variations in the data above and beyond the obvious and quite apart from the influence of fluoridation on oral health then do something about it. Analyse the data. Determine if what you are seeing is a statistically significant effect. See if you can suss out any other factors contributing to oral health that might explain the 5yo data.

    And write it up on your own blog.

    But you are really indulging in cherry-picking and rigidly narrowing your blinkers if you jump on to a few years data, ignore the rest of the data and the findings if others and claim it proves that fluoridation has not improved oral health. That somehow basic chemistry has changed.

    I can envisage plenty of other factors, including other sources of F intake, to “explain” that short period of data and age group you have cherry picked. None of those factors disprove the obvious advantages of fluoridation. Nor can they be anything than speculation without the collection of other social and dietary factors which aren’t in this database.

    But, as I say, I look forward to an article in your blog discussing the data and your speculations.

    Just be aware that by itself you are not warranted in drawing the conclusion from the data that fluoridation does not improve oral health.


  20. Ken, for the benefit of everyone, especially me, can you please explain your understanding of the “chemistry of bioapatites” and how fluoridated water has affected that?

    Then could you explain why decay has declined in BOTH fluoridated and non-fluoridated areas, and why that decline has generally been GREATER in non-fluoridated areas than fluoridated areas as shown in your graphs?

    Then could you explain the “chemistry of bioapatites” and how fluoridated toothpaste has affected that?

    Then maybe, you could explain the the “chemistry of bioapatites” and how sealing teeth with fluoride and chlorhexidine sealants has affected that?


  21. Ron, are you saying that fluoride increases tooth decay? Because the data I have described above disprove you. There is quite a large decrease in decay for the fluoridated group compared with the non-fluoridated group 0.48 for the 5 years group and 0.63 for the year 8 group.

    We all know about confirmation bias but you are getting ridiculous.


  22. Ken, unless you can explain things according to RonL’s personal satisfaction…then he automatically wins.
    ‘Cause that’s how science works.

    Your clever insisting that RonL analyse the data himself or making his claims more specific or getting him to suggest mechanisms is…well…a cheap and nasty trick to distract him. Nobody does that. Nobody!


  23. Well Ron, considering that, as it stands, I’m not satisfied the data says any such thing, perhaps you ought to consider making it your goal. You appear to think that we will simply take your assertions on faith, whereas I for one expect something a tad more substantive than your personal impression of trends after eyeballing graphs of data over a ten year period.

    A bit of analysis for statistical significance would be an excellent start, and perhaps you might consider tracking the data back further in time, since this will supposedly strengthen your case that the gap between fluoridated and non-fluoridated populations has narrowed.


  24. Ken, I’m lost.

    Your graph for 5yo above for DMFT shows and increase in average nuber for fluoridated children doesn’t it?

    Starts off at about 1.3 and finishes up about 1.8… the green triangles. The trend is obviously upwards. (ie, decay on average getting worse.)

    Conversely, the red triangle starts at about 2.3, wanders up a bit then gradually declines to about 1.9… giving a grand difference of about 0.1 DMFT.

    Are you saying that is wrong?

    If you look at the % caries free for five year olds then any disparity that existed at the beginning of the time period had all but disappeared by the end of the decade. Are you disagreeing with that observation of your own graph? My take on your graph is that that pattern exists for both maori and total…

    Are you saying that your graph is wrong?


  25. Chris, what are you saying the data doesn’t say?


  26. Ken, thanks for the copy of the paper. The first thing I looked at was the data… I note that 1,058 Children aged 4–9 have completed Completed university/college… these are obviously smart kids! 🙂


  27. Ron, you are pretending to be lost – take of your blinkers and stop your cherry picking and you will see clearly what I have said and should not have to keep repeating for you.

    The NZ data for the years 2002 – 2011 show an 8.1% (12.5% for Maori) greater carries free for 5 year olds and an 8.9% (10.4% for Maori) greater carries free for year 8 for fluoridated compared with unfluoridated.

    They also show a 0.6 (1.4 for Maori) lower mdmf for 5 year olds and a 0.5 (0,8 for Maori) lower mdmf for year 8 in the fluoridated compared with the unfluoridated group.

    It is blatantly incorrect to claim the data shows no difference between fluoridated and unfluoridated, or that the unfluoridated have better oral health as you have been claiming.


  28. I guess you realise you make fool of yourself by displaying publicly your inability to read a scientific paper or table.


  29. Ron, for Zog’s sake, take a course on statistics and actually go away and analyse the data. I’m not going to do it for you, and I’m certainly not going to agree with you on the basis of work you clearly haven’t done.

    The data may, just possibly, provide evidence in line with your beliefs. Then again, it may not. That is, your perceived trends may not be statistically significant. Cherry-picking data points is no substitute for actual analysis, and is not going to go down well with a sceptical audience such as you face here.

    As it stands, I am prepared to draw two conclusions from data:
    1) Over the period covered, there has been a clear difference in dental health between fluoridated and non-fluoridated populations.
    2) There is a clear difference in dental health between Maori and the general population.
    Beyond that, I make no definitive statements about what the data does or does not say, though further analysis may indeed reveal other patterns.


  30. Ken says, “As it stands, I am prepared to draw two conclusions from data:
    1) Over the period covered, there has been a clear difference in dental health between fluoridated and non-fluoridated populations.
    2) There is a clear difference in dental health between Maori and the general population.”

    What he conveniently ignores is that the divide has been getting less and less with time… that oral health gradually decreased in 5yo over time and that oral health in unfluoridated areas improved.

    What Ken also acknowledges is that cause and effect has been determined.

    In other words, it would be unscientific to use this data to support the claim that children benefit from the addition of fluoride to reticulated water.


  31. Just so we’re clear, Ron, I said that, rather than Ken.

    And I’m still waiting on the statistical analysis to back up your assertions. Get cracking.


  32. oops… apologies Ken (and Chris.)

    I’ve read the paper… to me it seems the evidence and analysis doesn’t demonstrate significant benefits of fluoridation…

    I’ve sent the paper to two scientists in the USA for comment… I asked them this…

    “Hi xxx

    Am trying to get my head around the claimed benefits of fluoridation of reticulated water supplies.

    What would be your take on this study? One side says it demonstrates effectiveness the other says it show fluoride doesn’t work.

    One is a member of the NAS who specialises in risk management in health and environmental issues, the other a professor in engineering.

    I’ll see what they say. As my reading of it stands, the paper has nothing to do with cause and effect. The paper refers to lifetime [exposure to fluoridated water] 57 times and makes no mention at all of breast feeding. Exclusively breastfed children would have no exposure to fluoridated water for a significant portion of their life while teeth are actually forming.
    In theory, non-breastfed babies living in fluoridated areas should have the best teeth in town given their mostly over-exposure to fluoride. As far as I am aware, that is not the case… if it were, that would be a more compelling case for fluoridation.

    Is there science that shows that formula fed babies in fluoridated areas have the best teeth in town?


  33. Who are these mates of yours, Ron? Names and affiliations?

    And why are you so flumoxed by the paper? Are you afraid to criticised FANNZ for their dishonesty?

    What a cop out!


  34. Would you mind linking to the paper in question, Ron? I seem to have missed it.


  35. In theory, non-breastfed babies living in fluoridated areas should have the best teeth in town given their mostly over-exposure to fluoride.



  36. OK, can someone decipher this? No doubt I’ve cherry picked, so please quote the science and statistical analysis that demonstrates a strong effect of fluoridation improving the wellbeing of teeth.

    “Looking at the deciduous dentition, in the first model, per cent lifetime consumption of nonpublic water was entered with age and sex as covariates for children who had had no access to fluoridated water across their lifetime (see Table 5). The relationship between consumption of nonpublic water and dmfs scores was not significant, P > 0.05. In the second model per cent lifetime consumption of nonpublic water was entered with age, sex, family income, parental education, occupational prestige, family type, residential location, frequency of brushing with fluoridated toothpaste and fluoride tablet use.

    Again, the relationship between consumption of nonpublic water and caries experience was not significant. Similar results were apparent for both models under the second condition, mixed lifetime access to fluoridated water. Again, in both models the relationship between consumption of nonpublic
    water and dmfs was not significant. However, under the third condition, children who had spent their entire life in localities with fluoridated water available, the relationship between consumption of nonpublic water and dmfs scores was significant after controlling for age and sex. Indeed, after controlling for age, sex, income, education, occupational prestige, family type, residential location, frequency of brushing with fluoridated toothpaste and fluoride tablet use the association between caries experienceand per cent lifetime consumption of nonpublic water remained significant, although the effect size (measured using partial eta-squared) of this relationship was small ( η 0.01).

    Running the same series of models, this time using the permanent DMFS scores as the dependent variable (see Table 6), it can be seen that the effect of consumption of nonpublic water on caries experience was not significant for either of the models under any of the three conditions of access to fluoridated tap water.”


  37. Richard, are you not familiar with the literature?

    J Public Health Dent. 2010 Fall;70(4):285-91. doi: 10.1111/j.1752-7325.2010.00183.x.
    Dietary fluoride intake for fully formula-fed infants in New Zealand: impact of formula and water fluoride.
    Cressey P.

    Food Safety Programme, Institute of Environmental Science and Research Ltd. Christchurch 8540, New Zealand. peter.cressey@esr.cri.nz

    A survey of the fluoride content of infant and toddler formulae available on the New Zealand market was conducted. Results were used to estimate the dietary fluoride intake for a fully formula-fed infant.

    Infant and toddler formulae were prepared according to manufacturers’ instructions with fluoride-free water and analyzed for fluoride by a modification of the microdiffusion method of Taves. A proportion of samples were reanalyzed after reconstitution with water at fluoride concentrations of 0.7 and 1.0 mg/L. A stochastic model was used to estimate dietary fluoride intake.

    The mean fluoride content of prepared infant formulae was 0.069 mg/L. When formulae were prepared with water of differing fluoride concentrations, the fluoride concentration was found to be a simple linear function of water fluoride concentration. Estimates of dietary fluoride intake for infants consuming formuae prepared with fluoride-free water were well below the upper level of intake (UL) for New Zealand and Australia (0.7 mg/day). At water fluoride concentrations of 0.7 and 1.0 mg/L the UL would be exceeded 30 and 93 percent of the time, respectively.

    The fluoride content of water used to reconstitute infant formulae has a greater impact on fluoride intake of fully formula-fed infants than the fluoride content of the powdered infant formulae. Infants fully formula-fed on formulae prepared with optimally fluoridated water (0.7-1.0 mg/L) have a high probability of exceeding the UL for fluoride and are at increased risk of dental fluorosis.

    From the original report,

    The estimates for a fully formula-fed infant exceeded the UL approximately one-third of the time for formula prepared with water at 0.7 mg fluoride/L and greater than 90% of the time for formula prepared with water at 1.0 mg fluoride/L. However, it should be noted that the current fluoride exposure estimates for formula-fed infants are based on scenarios
    consistent with regulatory guidelines, rather than on actual water fluoride concentrations and observed infant feeding practices. Similar research recently undertaken by Food Standards Australia New Zealand has also concluded that a proportion of children up to 8 years could exceed the UL when fluoridated water (0.6 – 1.0 mg/L), from any source, is consumed. The use of fluoride-containing toothpastes will provide an additional contribution to total fluoride exposure.

    And just remember that the amount present in water has little relationship to the dose of fluoride consumed.


  38. Tell you what, Ron, why don’t you distill down what you think the study means, that way we can read through it and tell you whether we think you’re right, and if not, where you’ve gone wrong.

    I’ll be taking the time to read the full study, rather than just the snippet you’ve provided.


  39. Also, if you are going to reference papers, please provide a link so that the rest of us can read through the whole thing, rather than relying on the snippets you see fit to provide.

    I seem to recall that the official advice to parents is to prepare infant formula using distilled water, so as to avoid precisely this issue. Indeed, this would apply to unfluoridated water as well, since natural fluoride concentrations will vary from location to location.


  40. Okay, looks like I’m wrong. Actual guidelines come from here:

    I would need to see the full paper before commenting further, because I suspect important information has been omitted.


  41. The MOH link doesn’t work.

    Try this link to the ESR website

    Click to access FW0651-Fluoride-intake-assessment-July2009.pdf


  42. Chris, haven’t you been able to get the paper yet? Or have you and realised the above is a cut and paste?


  43. Ron, I am well aware that is a cut and paste.

    Your use of “or” suggests that you think that I asked for the paper only for the sake of verifying that the quotation was accurate. This is not correct.

    Now, I am not going to rush to comment on this, as I have not yet had the opportunity to read the paper. You appear to have far more free time on your hands than I do, and in addition, have been reading up on the topic for much longer.

    Alas, so far, my impression has been that your reading has been highly geared towards confirming your particular bias, rather than any balanced or objective consideration of the science.

    As it stands, however, I am satisfied that there is rather more information to take into account than you saw fit to provide in your chosen quotation.

    Still, while I’m doing other things, perhaps you might care to treat us to your distillation of what you think the Armfield & Spencer paper says?


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  45. RonL, thanks for clearing up identity and some of the content of the paper you were writing about.
    In regard to your question Richard, are you not familiar with the literature? I must answer absolutely not. Nor even any meta analyses of relevant material. That is why, I rely on what Cedric refers to as “mainstream scientific sources”, in this case the judgement of the scientific community and public health authorities throughout the world. The very organisations equipped and charged with analysis of the science and data in this field. Not being professionally part of that field it is not for me to gainsay their conclusions, no matter how well-qualified I think a few hours on Google may make me.


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  47. Ron, this shows you can post images here — you just can’t upload them to my blog space. Just upload it to your own space and put the address of your image in the appropriate code.

    The figure shows why selecting just 2 data points and drawing a straight line hides a lot of important data and conveys the wrong message.


  48. Good for you Ken… you own the blog. My point on the other discussion has been that I can’t paste a graphic on here. Now be honest… post the two graphs I sent. Also, repeat your effort above but do the trend line electronically… If you now did the above graph with a number of fluoridated and non-fluoridated countries you’d see the dramatic declines that pro-fluoridation folk like yourself tout about occurred in BOTH fluoridated AND non-fluoridated countries at similar rates… if you plot the two in New Zealand you’ll see the same near parallel rates of decline.

    The BMJ article didn’t Just select two datapoints. They plotted the trends…

    If you look at figure 1 here you can see that they didn’t use just two points… so be honest.

    Check out Figure 1

    Click to access hampshire.county.nov08.pdf

    Their graph also finished at 2000… not 2010 as you have it… so be honest.,.. repeat your graph finishing at 2000… the difference isn’t so great.


  49. You don’t paste it Ron you use the img code. You managed it before with a video.

    Post your images of use shut up. You are only making excuses for your own ineptness.


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  57. Interesting discussions between both sides of the fluoridation issue on this site – I think this is helpful. I remember when opponents first talked about the Armfield & Spencer 2004 Australian study. They reported it as you wrote it, regarding the potential benefit of fluoridation: “This was found for deciduous teeth, but not for permanent teeth and the authors speculated on the dietary and other reasons for this.” The strong belief in fluoridation by the authors and whatever they wrote does not take away the results which showed little or no benefit to permanent teeth. Yes, there are current studies that show fluoridation is still effective in for permanent teeth, but not this one which was a pretty large study. So there is evidence on both sides of fluoridation’s effectiveness today – ranging from significant, to very small, to none. But notice that in the U.S. there have been no more national surveys of children’s teeth since the freedom of information act was passed. That act meant that the actual data from the 1987 large scale national study could be obtained by outsiders, and the actual data showed far less or no effectiveness in 1987, depending on how you analyze the data. DMFT: no benefit, DMFS: slight benefit which might not even be statistically significant. The increasing ineffectiveness of fluoridation is a reason opposition has grown.
    Decades ago in the U.S. fluoride researchers had to satisfy the agencies that funded their research, so they had to write their abstracts very carefully. When they found damage from fluoride they typically would write things like “this result does not apply to fluoridation” even when it logically would apply to fluoridation. So the facts and research results presented in fluoride studies do not always agree with the authors abstract. Decades ago fluoridation was heavily promoted in the U.S. by high level experts like Harold Hodge who said fluoridation was good for old people’s bones. Today I don’t see fluoridation promoters using any statements like Hodge did. And it seems researchers have finally given up on testing sodium fluoride as a treatment for osteoporosis.


  58. Great discussion. Unfortunate that it gets a little nasty near the end. Expecting someone to know how to extract an image from a PDF file, upload it somewhere, and then insert the appropriate HTML into a comment is probably expecting too much for the general population. As you may know, videos online generally already show an embed code for people to easily copy and paste, so embedding a video would be much easier for Ron than extracting, uploading, and embedding an image from the report. It is so refreshing to read through an actual dialogue that answers questions and analyzes data. I have enjoyed reading the comments on this blog because the level of discussion is much higher than in many handouts, so thank you for creating this space. IT Is very true that anti-fluoride commentators are often illogical and abusive, but that doesn’t seem to be the case with Ron, from what I have read.


  59. The main problem with Ron has been harrasment. I have had to moderate, remove, a lot of his more recent posts. We will see how he behaves with the debate posts.


  60. Hmmm… It’s hard to see that from what’s posted here. He seems fairly sincere and interested in your response. Then again, this is the only thread I’ve read where he has commented, so I’ll take your word for it.


  61. Testing to see if the html img tag works.


  62. Ken, it looks like html image tags are not allowed for users commenting on your site. Typically, img tags are not allowed for users under the WordPress default options, only for the admin and this can be changed by modifying the appropriate php file…


  63. You can also install the plugin html purifier and add the tags you want to allow that way.


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