FLUORIDE 30 (2)
1997, pp 136-139		 International Society for Fluoride Research Table of Contents
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REPLY TO CRITIQUE

Thank you for drawing our attention to Mr Wilson's comments (Fluoride 30 (1) 71-72 1997) on our paper. The purpose of this study was to contribute some factual information into the ongoing debate on whether communities are becoming exposed to more and more fluoride - and whether this can be considered excessive. The study was only coincidently relevant to previous published papers by Cutress et al (1985) or Colquhoun (1984). Mr Wilson's supposition that this study was set-up to disprove Colquhoun's or any other study is surprising and quite without substance. Anyone knowledgeable on the issue knows full well the difficulties of debating the subject objectively. Reliable and comparable data bases (diets, urine, hair etc) stretching across 30 years are simply not available - this we explained in our paper. Teeth, of course, are the most lasting of human tissues and also a marker of exposure to fluoride during a specific developmental period. Our approach was unique and made possible only because of a collection of teeth with reasonable data on the donors and access to the sophisticated methodology. While Mr. Wilson may be of the opinion that "their latest study itself diminishes support for fluoridation", he provides no logic to support this personal viewpoint. On the other hand we did. Even if our two papers (1985 and 1996) were indeed at variance (which they are not) this would not be a problem. As investigators we are not wedded to a 'conviction' or determined to hold to a conclusion if new evidence advances our knowledge. While we are of the opinion that the need for 1 ppm fluoride in water is less necessary now than 30 years ago we still advocate an average daily exposure to 1 mg fluoride sourced from water and other source, - toothpaste in particular.

Mr. Wilson is, however, correct in identifying some imperfections in the study.

  1. Sample size: we would, of course, have wished to include more teeth in the study. Our small numbers were the end result of a careful selection from a large number of teeth taking into consideration age, geographic origin, period of tooth development. A statistically relevant sample size is desirable but not always possible. I would point out that it is not possible to obtain such teeth by mail order; teeth formed in the 1950s are not being made any more! On Mr Wilson's rationale most of the science human anthropology would be discarded based as it is on fragments of bone and teeth from a few individuals.
  2. Age and scattergrams discrepancies: these are minor matters which do not significantly alter the findings. We are confident that we got it 99%+ right - for Mr Wilson to use these few indiscretions to claim that they, 'lessen any confidence in the conclusions' is a distortion of commonsense.
  3. History of teeth: Mr. Wilson does not state what other history details he would find useful. We thought a congratulatory comment would have been in order in recognition of the foresight we had to accumulate, over 35 years, a valuable tooth bank documented with details of age and origins.
  4. Credibility of the fluoride content of teeth: we are uncertain of Mr. Wilson's criticism. The value of using F profiles is increased because of the relative short period of development incorporation. The tooth holds a record of F availability during a known, short time frame. This ensures a more precise measure of F exposure over a matter of just a few years. Hence the remarkable consistency of the F profiles we found across the deeper enamel and the dentine. This is in fact a strength not a weakness of our evaluation procedure. The fluoride locked into the enamel/dentine is a sound marker of the F environment of the time. The fluoride content of the bulk of enamel and dentine remains constant until the tooth is destroyed.
  5. Computer generated mean values: the suggestion of the value of computer generated mean values is again for our situation academic. The work involved would have been substantial - when commonsense indicated that differences between visually estimated and computer calculated values would not have been significant.
  6. Colquhoun article (1984): reference to this paper was of passing interest as was the balancing reference to Cutress et al (1985). We would take this opportunity to expand and again emphasise the well-known fact (60 years) that fluorosis is associated with the prevalence of fluoride and hence when water level of fluoride naturally occurring in drinking water is supplemented, say upwards to 1 ppm from 0.1 ppm, then the prevalence of very mild fluorosis increases - in fact it becomes the same as in people drinking water with natural levels of 1 ppm fluoride. We saw no reason to engage in, for this paper, irrelevant discussion - a reference was sufficient.

As Mr. Wilson raised the point, we would further comment that our suggestion (1985 paper) that the level of fluoride in drinking could be reduced without risk of caries increasing was based on the present contribution of fluoride from toothpaste. A reduction in water fluoride concentration would probably reduce the prevalence of minor fluorosis which occurs at 1 ppm.

T W Cutress
Wellington School of Medicine
Dental Research Group
PO Box 7343
Wellington South, New Zealand

REJOINDER

In spite of the assurance that the reference to Colquhoun's 1984 paper1 was coincidental, the fact remains that they cited this paper, which reported that the prevalence and severity of dental fluorosis has increased, without citing their own 1985 paper,2 which reported very similar data. They then presented data in the 1996 paper, which claimed to show only "optimal" fluoride levels.

I thank the authors for providing the logic supporting my statement that "their latest study diminishes support for fluoridation". Answering the six points:

  1. One of the "imperfections" in their study is that the sample sizes are not statistically relevant, which the authors implicitly accept. It follows that the comparison of statistically irrelevant mean values with a " highly debatable" data base is of little value. The authors' view, about my rationale, of " human" anthropology (are there other kinds?) is wrong. That science has never advocated adding cumulative toxins to water supplies without informed consent.
  2. I note the authors' preference for commonsense rather than accuracy.
  3. The authors' silence, about the availability of more detailed history of fluoride exposure during the teeth development years, again implies the invalidity of this comparative study.
  4. It is true that the teeth hold a record of F availability over the development period. However the small sample sizes and insufficient detail of the history of the teeth do not add strength to this particular study.
  5. I note again the authors' preference for the commonsense view rather than accuracy. Computer programs to handle statistical evaluation of this type of data are almost certainly available at any university. I wrote such programs in the 70s and 80s.
  6. The 1984 and 1985 papers are of more than passing interest because this 1996 study claimed that fluoride levels are not excessive. The 1984 and 1985 papers reported 3.6% pitted and discoloured teeth and 2.5% occurrence of cosmetically poor or doubtful teeth respectively in fluoridated areas which, according to the 1996 paper, occurred at "optimum levels" of fluoride. This contradicts the assertion that only minor fluorosis ensues at this level, indicating that fluoride levels are indeed excessive. Further, the 1984 and 1985 papers reporting almost identical levels of dental fluorosis (24.9% and 25% respectively) plus the 1985 authors' admission that "a reduction of the water fluoride concentration would probably reduce the prevalence of minor fluorosis which occurs at 1 ppm", strongly supports Colquhoun's position that fluoride levels are too high.

Many people will drink at least two litres of liquid during a hot working day followed by a few drinks with friends after work. It is easy to deduce from first principles that these people will ingest well above 2 mg, when fluoride from food, soft drinks, toothpaste etc is also taken into account. Many fluoride papers resemble the theological debate about how many angels can dance on the head of a pin. Since it is now accepted that the topical effect of fluoride predominates, water fluoridation is unnecessary and the dubious benefits of fluoride can be provided by toothpaste. This would restore free choice to those who have no wish to ingest this cumulative toxin and wish to lessen the environmental pollution by fluoride and its associated heavy metals.

Bill Wilson
118 Forrest Hill Road, North Shore City
Auckland, New Zealand

REFERENCES AND NOTES

  1. Colquhoun J. Disfiguring dental fluorosis in Auckland, New Zealand. Fluoride 17 234-242 1984. (Reported previous year's survey of dental fluorosis prevalence among 7-12 yr-old children: in fluoridated areas 24.9%, with 10% having front teeth affected and 3.6% having discoloured or pitted enamel; in non-fluoridated areas only 4.9% had very mild fluorosis.)
  2. Cutress TW, Suckling GW, Pearce EIF, Ball ME. Defects in tooth enamel in children in fluoridated and non-fluoridated water areas of the Auckland Region. New Zealand Dental Journal 81 12-19 1985. (Reported bilateral "diffuse mottling" prevalence among 9-yr-old children: in fluoridated areas 25%, with 15% having front teeth affected and 2.5% having "cosmetically poor" or "cosmetically doubtful" appearance; in non-fluoridated areas overall prevalence was not reported, but 4.25% had front teeth affected and none of these had cosmetically "poor" or "doubtful" appearance.)

OPTIMAL INTAKE: PROFESSOR JENKINS REPLIES

Dr Foulkes writes (Fluoride 30 73 (1) 1997) that my description of fluoride as an "inessential food constituent with beneficial effects" is based on my belief that fluoride makes a useful contribution to health. I certainly do believe this, being familiar with the world-wide evidence and having seen the effect in my own city of Newcastle upon Tyne. I do not deny, of course, that high doses of fluoride are toxic but if, as Dr Foulkes writes, "there is no minimum safe dose" then the whole human race must be at risk as no human food or drink is entirely free from fluoride. Can Dr Foulkes tell us what the signs and symptoms are of this alleged toxic effect from which he thinks we are all suffering?

G Neil Jenkins
4 Jesmond Dene Terrace
Newcastle upon Tyne, NE2 2ET England

DR FOULKES RESPONDS

Of course, Professor Jenkins is correct in his statement that "no human food or drink is entirely free from fluoride". But, as he is aware, fluoridation has increased the dietary burden for both those living in fluoridated communities and those who do not, by virtue of the "halo effect".

Perusal of back issues of Fluoride alone shows a number of possibilities associated with this increased burden. It would require no genius to construct the signs and symptoms that may represent the possible clinical effects. These could range from the obvious dental fluorosis to chronic dyspepsia, tendonitis, stiff back, arthritis, abnormal electrocardiogram, etc. I suggest that he re-read Kaj Roholm's treatise 1 and recognize that the level of daily fluoride intake that Roholm postulated for osteosclerosis is now reached or exceeded by those who are residents of fluoridated areas for 20 to 40 years.

A problem is encountered in obtaining "proof " of a fluoride etiology for the vague symptoms encountered in medical practice. This requires a high index of suspicion that most physicians lack, and adequate laboratory and imaging resources. In most areas, these are either incompetent or unwilling to participate in confirming a suspicion of chronic fluoride intoxication.

Roholm1 expressed his difficulty in establishing a minimum dose and time interval for osteofluorosis due to industrial exposure. He did not have to deal with the "paradoxical effect" and the possibility that very low levels of fluoride acting on the fetus may have disastrous effects. It was this latter that inspired my comment regarding the lack of knowledge concerning a minimum safe dose.

Professor Jenkins and I see the fluoridated world in the context of' different belief systems. Perhaps we can discuss these some day over a pint in Professor Jenkins' local or in the Bellingham Marina in 1998.

Richard G Foulkes
PO Box 278
Abbotsford BC, Canada

  1. Roholm K. Fluorine Intoxication: A Clinical-Hygienic Study. H K Lewis, London 1937.
FLUORIDE 30 (2)
1997, pp 136-139		 International Society for Fluoride Research
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