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Draft NHMRC Information Paper: Effects of water fluoridation on dental and other health outcomes submission

ID: 
8
This submission reflects the views of
Individual Background: 
Water Industry Chemist
Personal Details
First Name: 
David
Last Name: 
Smith
Specific Questions
Q1. A) Is the draft Information Paper presented in a manner that is easy to understand? : 
Neutral
Q1. B) Please provide details regarding your response to Question 1A: 
Evaluating the evidence – Critical appraisal of the evidence

Submission on the Efficacy of Low Levels of Fluoride in Drinking Water

David Smith

 

Abstract: Fluoride has a proven role in both making healthy enamel more decay resistant and remineralising decaying enamel. This efficacy is demonstrated when applied to cleaned teeth in vitro. The efficacy of low levels of fluoride in drinking water applied to plaque coated teeth in vivo (as the only source of fluoride), is questionable as is the extent of the anti-microbial effect of enamel bound fluoride on cariogenic bacteria.

 

The use of fluoride toothpaste on the other hand, appears to be an effective decay prevention strategy as it applies a high concentration of fluoride topically for a sufficient period of exposure at a time when teeth are at their cleanest. It is thus unlikely that individuals with good dental hygiene will benefit from water supply fluoridation. Conversely, there is little quality evidence that an individual who does not brush and floss well regularly can expect to avoid caries merely through exposure to drinking water fluoride.

 

The decision to mandate the dosing of a chemical into the water supply is serious and in the case of fluoride, makes it difficult for dissenters to avoid exposure. The decision to mandate any chemical into the water supply requires strong evidence that there is an unambiguous benefit and that such benefit far outweighs any possible harm associated with the practice. Further, the case for dosing would have to be made to the public. Normally a significant challenge to universal public health would have to be demonstrated. It is difficult to believe that the rate of caries in non-fluoridated areas of Queensland (for example) prior to legislation was ever a significant challenge to public health and there is good evidence that the caries prevention credited to low levels of fluoride in drinking water are overstated.

 

The dosing of fluoride into drinking water carries the risk of dental fluorosis that is more than just a cosmetic concern and it introduces a reactive element into the circulatory system where it can possibly have unwanted consequences.

 

With regards to dosing fluoride into the water supply, the case for clear benefit does not appear as strong as originally thought by proponents and this is without even considering any possible harm associated with the practice.

It appears that people with good dental hygiene will see no benefit and those with poor dental hygiene will also see no benefit. It is possible that people in between will experience a variable benefit according to where they are in the spectrum. This is not quantified and in any case would not amount to a basis for mass medication through the water supply.

 

Background: The author of this submission has qualifications in chemistry and biochemistry. The author also has 20 years of experience in the quality control of drinking water and recycled water having been employed at Caboolture, Gold Coast, Melbourne and South East Melbourne water authorities.

The author is not (nor has ever been) part of any group or organisation with any fluoride agenda.

This submission is not made on behalf of a water utility.

Around 2002-2003, water levels fell to a low level on the Gold Coast and there was concern from the medical profession about the safety of the water as the dam levels sunk lower. The Director and the author made several presentations around this topic and others to AMA meetings on the Gold Coast. After the talks on a few occasions we were approached by one or two doctors asking why we didn’t fluoridate the water. We didn’t have an opinion on the topic and just said that it had been voted out years ago and that there had been no recent discernible community interest in its reintroduction. These individuals were quite passionate about fluoridation.

Around 2004 the Queensland Dept. of Health wrote to the Gold Coast City Council suggesting that Gold Coast Water (GCW) should introduce fluoridation of the drinking water supply. The director of Gold Coast Water referred the letter to the water quality coordinator (the author of this submission). The Dept. of Health suggested that GCW should consider the York report to see that fluoridation would be an act of beneficence. The issue of fluoridation was not under consideration by GCW at the time and there was no prejudice one way or the other towards the topic. The Quality Control Coordinator (a chemist) appointed two PhD chemistry staffers to review the York report. One of these chemists is now with [NHMRC has removed thrid party information] and the other has gone on to pursue a career in medicine. At the time, the references quoted in the York report were accessed (and some of the references within these). The chemists reported that they had a similar view to York University in that fluoridation may be of some marginal benefit but was hampered by a lack of evidence of its efficacy when applied to uncleaned teeth. We were surprised that QH were so enthusiastic about the York report as we did not see clear support manifest in the text.

After some months GCW informed the Health Dept. that some decades earlier, the citizens of Gold Coast had decided against fluoridation and that after reading the York Report (and references) the current staff were unable to see sufficient benefit in reintroducing fluoride. GCW suggested that if the Dept. Of Health wanted GCW to fluoridate than they should act to mandate the practice as we had no public pressure, no evidence of need and little evidence of beneficence. The Dept. of course did so a few years later.

The Author left GCW in 2005 to work at [NHMRC has removed third pary information] where fluoridation had been practised since 1973. Fluoridation is not particularly popular with [NHMRC has removed third party information] staff as the fluoro silicic acid is unpleasant for workers and has corrosive fumes. Each load for dosing is accompanied by a lab report showing the levels of contaminants and these are supposed to be checked against the product specification before dosing. The author has been at South East Water in Melbourne since 2008 primarily managing the quality control of recycled water. Fluoridation is rarely discussed in water authorities and is mostly just regarded as a regulatory responsibility. Operationally, its removal would be welcomed.

It seems that early research on cleaned teeth set the stage for the belief that fluoride was the silver bullet for caries protection and much of the enthusiasm in medical and dental circles probably stems from this work in the 80s and 90s. It is doubtful if all of these supporters have closely read the original literature. The media have bought into this belief and we now see journalists with no scientific training whatsoever fearlessly branding anti fluoride people as fringe lunatics. That sort of behaviour is usually a sign that hype is at work.

 

Discussion: The researchers Hicks, Silverstone and Featherstone are prominent in the papers referenced in the York report and these workers have shown that fluoride can not only prevent decay in tooth enamel but can also repair damaged enamel. In order to demonstrate the performance of fluoride, these workers used cleaned teeth that had been extracted by orthodontists.

Hicks et al (Ref: 1) suggest that fluoride incorporated into cleaned enamel might act against plaque bacteria but they say high levels are required for some bacteria. However, the work they did perform was on cleaned teeth. Ref: 1/1 (Clarkson et al) is similar.

Silverstone et al (Ref: 2) show the efficacy of fluoride rinses (0.2% or 2000ppm). As with the previous references, they do not specifically promote fluoridation of the water supply and of course possible adverse events associated with ingesting fluoride are not in scope. Further Silverstone et al in another paper (ref: 3) suggest a high Calcium solution with 1ppm fluoride gives best effects (on clean teeth) and that after five x 6 minute exposures, 80% of the benefit was achieved. The kinetics are thus quite rapid.

Ref 1/5 (Hicks et al) is similar suggesting a 0.2% NaF solution rinse is effective with 5 minute exposures. They advocate low concentrations with frequent exposure which suits the approach of dosing drinking water. Again the work is on cleaned teeth.

Ref: 4 (Den Besten) indicates that dental fluorosis is more than just the appearance of white spots on tooth enamel. The author shows that the tooth enamel is structurally weakened and damaged by the fluoride. The extent to which this occurs is determined by cumulative exposure.

Ref: 5 (Limeback) concentrates on the failure to differentiate between the systemic and topical effects of fluoride. Limeback says that if you are fluoridating the water supply, the use of additional fluoride supplements on children under 3 might be harmful.

Ref: 6 is by the confident and influential John Featherstone. He claims that fluoride acts topically (not systemically) on three fronts. Two of these (prevention of enamel mineralisation and remineralisation of damaged enamel) have been demonstrated. The third is more controversial. That is, that fluoride incorporated into plaque inhibits the action of plaque bacteria. Featherstone cites workers who suggest that the H+ ions from fermented organics in the plaque combine with F- (from NaF) and form HF which then enters the plaque bacteria and impairs activity. Other authors (G Bowden & I Hamilton) not cited here have since carried out further work in this area and are not as decisive about the net effect of the anti-microbial effect of fluoride on cariogenic bacteria. Featherstone himself acknowledges the complexity of this topic and mentions that the chemistry at the plaque/enamel interface varies during the day. Interestingly, when interviewed in 2012 Featherstone laments fluoridation “did not solve the problem to the extent it was hoped”. 

https://www.dentalaegis.com/id/2012/06/a-conversation-with-john-d-b-featherstone

That fluoride exhibits cytotoxic qualities and interferes with metabolic enzymes is of interest given it is ingested through drinking water and many metabolic enzymes are shared in the planet’s numerous life forms.

 

Ref: 7 (Hicks et al) is more recent (2004). This paper reinforces the role of fluoride in reducing caries but emphasises its catalytic role such that far smaller amounts are effective than previously thought necessary (page 208).

Hicks further states that remineralisation of enamel is limited when there are organics substances attached to the enamel (contact cannot be made).

Page 208; “……. With constant bathing of the carious lesions by saliva following periodic plaque removal, reversal of a lesion by endogenous saliva is possible.

Page 211; “Although systemic fluoridation in the form of water fluoridation has been touted in the past for the decline in dental caries, it has been realised that the primary reduction in dental caries is because of the topical effect of water fluoridation and the availability of fluoridated toothpastes. In several European countries without water fluoridation, a similar level of caries reduction was found following introduction of fluoride-containing toothpastes.”

That fluoride toothpaste would provide a high level of caries protection makes sense since the concentration of fluoride in toothpaste is orders of magnitude greater than drinking water and the kinetics of the reaction with enamel are rapid and the enamel is well exposed (from the brushing) at the time of exposure. Reviewers will realise that the rates of all chemical reactions are influenced by (among other things) the concentrations of the reactants, the reactivity of participating species and steric conditions. Applying low levels of fluoride relies on the long contact time to overcome the low collision rate (i.e. low concentration of reactants) but the steric hindrance provided by plaque and food particles lodged in small gaps is a serious limitation.

These authors nevertheless believe there is a benefit in water fluoridation because one experiences some level of topical treatment from the traces of fluoride in the saliva. Again though the presence of plaque is recognised as problematic (despite the earlier claimed anti-microbial qualities of fluoride.)

High dose fluoride with less frequency does not help white spot lesions but is of help where high caries activity is occurring and where restorative work is required.

Plaque control is recognised as a major issue (page 212). Having been strong advocates of fluoridation in the past, it must be difficult for workers like Hicks et al to report observations that diminish its capability and cast doubt on its beneficence. Perhaps this explains their better than nothing offering.

 

The author of this submission has not personally experienced any reduction in plaque formation since moving from a non-fluoridated supply to a fluoridated supply 10 years ago. Indeed, it is demonstrable that fluoridation has no perceptible effect on plaque formation.

 

____________________________________________________

 

Ref 1: Fluoride uptake in vitro of sound enamel and caries like lesions of enamel from fluoride solutions of relatively low concentration.

Authors: Hicks, Flaitz & Silverstone

Source: Journal of Pedodontics (Vol 11:47, 1986)

 

Ref: 1/1 (reference 1 within paper 1) Redistribution of enamel fluoride during white spot lesion formation: an in vitro sturdy on human dental enamel.

Authors: Clarkson, Wefel and Silverstone

Source: Caries Res. 15: 158-165 (1981)

 

Ref 2: Dynamic factors affecting lesion initiation and progression in human dental enamel. II. Surface morphology of sound enamel and caries-like lesions of enamel.

Authors: Silverstone Hicks & Featherstone

Source: Special report- Quintessence International Vol 19 number 11 (1988)

 

Ref 3: Dynamic factors affecting lesion initiation and progression in human dental enamel. I. The dynamic nature of enamel caries.

Authors: Silverstone Hicks & Featherstone

Source: Special report- Quintessence International Vol 19 number 10 (1988)

Ref: 1/5 (reference 5 within paper 1) Initiation and progression of caries-like lesions of Enamel: Effect of periodic treatment with synthetic saliva and NaF

Authors: Hicks, Flaitz and Silverstone

Source: Caries Res. 19: 481-489 (1985)

 

Ref 4: Biological mechanisms of dental fluorosis relevant to the use of fluoride supplements.

Authors: Den Besten

Source: Community Dentistry and Oral Epidemiology 27: 41-47 (1999)

 

Ref: 5 A re-examination of the pre-eruptive and post-eruptive mechanism of the anti-caries effects of fluoride: is there any anti-caries benefit from swallowing fluoride?

Authors: Limeback

Source: Community Dentistry and Oral Epidemiology 27: 62-71 (1999)

 

Ref: 6 Prevention and reversal of dental caries: role of low level fluoride.

Author: J. Featherstone

Source: Community Dentistry and Oral Epidemiology 27: 31-40 (1999)

 

Ref: 7 Biological factors in dental caries: role of remineralisation and fluoride in the dynamic process of demineralisation and remineralisation (part 3)

Authors: Hicks, Garcia-Godoy, Flaitz

Source: Journal of Clinical Paediatric Dentistry Vol 28 No 3 (2004)

Evaluating the evidence – Critical appraisal of the evidence

Please see attached submission.

Q2. A) Is it clear how NHMRC reviewed the health and dental effects of water fluoridation? : 
Neutral
Q3. A) Is the Fluoride Reference Group’s interpretation of the evidence clearly described in the draft Information Paper?: 
Disagree
Q4. Is there additional evidence on the dental effects of water fluoridation that should be considered?: 

More of a case of the dental non effects.

Q6. Is there any other supporting material relevant to making decisions on water fluoridation in the Australian context that should be considered in the draft Information Paper?: 

The issues raised above should be addressed.
Excluding data prior to 2006 is absurd since the data showing the incorporation of fluoride into dental enamel is older than that and it is this data that underpins the decision to implement fluoridation in the first place. This submission challenges the conclusions drawn from that fundamental research and therefore challenges the efficacy of low levels of fluoride in drinking water.

Page reviewed: 4 July, 2017