Tag Archives: Fluoride Free NZ

Non-fluoridated Christchurch does not have better teeth than fluoridated Auckland

wrong

It seems every time anti-fluoride propagandists present data it is either cherry-picked, distorted or misleading. Often all three. So it is hardly a surprise to find local anti-fluoride propagandists are telling porkies again.

They have been promoting the above graphic claiming it shows people in “non-fluoridated Christchurch have “better teeth.” But the graphic is based on naive cherry-picking of the data, it ignores the effect different ethnic groups have on the data and it uses a single cherry-picked year which fits their bias.

On top of that, axis values have been chosen to exaggerate differences and the labels are incorrect. The “non-fluoridated Christchurch” category uses data for Canterbury and the “fluoridated Hamilton” category uses data of the Waikato.

It seems that several of the commenters on the Fluoride Free NZ Facebook page where this graphic was first used saw the problems and raised them. All they got is insults for their time. These organisations do not seem capable of a rational discussion.

The Ministry of Health data they use is freely available on the MoH website. It provides oral health data for 5-year-old children and year 8 children. The data is presented annually and for different regions.

So let’s have a look at what the data really says – using more normal axis ranges and separating out ethnic groups.

chch-real

The top graph here is still misleading because it does not take into account the effect of different ethnic groups. However, the correct categories are used and the more rational axis really cuts the exaggerated difference down to size.

In the second graphic the data for Māori and Pacifica have been removed – the MoH describes this group as “Other” – it is mainly Pakeha. We can see that the caries-free % is actually greater for fluoridated Auckland than it is for non-fluoridated Canterbury – exactly the opposite of what the anti-fluoride propagandists were claiming.

It is the same story for Māori – the caries-free % is actually higher in fluoridated Auckland than in non-fluoridated Canterbury.

The problem with the “Total” data is that Pacifica have a large effect – particularly in Auckland where Pacifica are concentrated. Pacifica generally have poorer oral health but are concentrated in fluoridated regions. This drives down the caries-free % figures for the fluoridated areas if the differences are not accommodated.

I referred to this effect of Pacifica on the data in my article A challenge to anti-fluoridationers to justify their misrepresentation of New Zealand research. There I was referring to a similar way anti-fluoride campaigners were misrepresenting data from recent New Zealand research. In this case, they were using data from a paper (Schluter & Lee 2016) and completely ignoring the distortions introduced by inclusion of Pacific – even though the authors had warned against the anomaly introduced by this.

There are other effects which should also be considered in a proper understanding of these data. It is easy to cherry-pick the data for a single year when differences are small – the anti-fluoride people do that a lot. OK if you want to confirm your biases but consideration of the data over multiple years helps indicate trends, identify anomalies and provide an idea of variations in the data. It is also important to consider the numbers in each region. For example, I have not included Pacific in the graphs above because they are concentrated in Auckland and the numbers in Canterbury and Waikato are very low (eg., 45 in Waikato in 2014).

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A challenge to anti-fluoridationers to justify their misrepresentation of New Zealand research

Challenge

One of the frustrations I have with the fluoridation issue is the refusal of anti-fluoride activists to engage on the science. They will pontificate, but they won’t engage in discussion.

On the surface, one would think there is a difference of opinion or interpretation of scientific issues and that could be resolved by discussion. Yet local anti-fluoride campaigners refuse to enter into discussion. Again and again, I have offered space here to local anti-fluoride campaigners so that they could respond to my articles and they have inevitably rejected the offer. They have also blocked me, and other people discussing the science, from commenting on any of their social media pages or web sites. Even when they, themselves, call for a debate they reject specific responses I have made accepting that call.

So I am left with the only alternative of responding to their claim with an article here – or on a friendly web or blog site. At least that gives me space to present my argument – I just wish I could get some intelligent responses enabling engagement on the issues.

Misrepresentations repeated

The latest misrepresentation of the science is a claim by the Auckland Fluoride Free NZ Coordinator, Kane Titchener, that recent research proves fluoridation [is] not needed.

It repeats the same misrepresentation made by Wellington Anti-fluoride campaigner, Stan Litras, which I discussed in my article Anti-fluoridation cherry-pickers at it again. Kane has either ignored my article, chosen to ignore it or possibly not even understood it.

So here we go again.

Kane claims:

“A New Zealand study published in Bio Medical Central Oral Health last month shows dental health improved the greatest extent for children in non-fluoridated areas. There is now no difference in dental decay rates between non-Maori children who live in fluoridated areas and non-Maori children who live in non-fluoridated areas, proving that fluoridation is not needed for children to obtain good dental health.”

Although he doesn’t cite the study (wonder why), his use of two figures from the study show he is writing about the paper:

Schluter, P. J., & Lee, M. (2016). Water fluoridation and ethnic inequities in dental caries profiles of New Zealand children aged 5 and 12–13 years: analysis of national cross-sectional registry databases for the decade 2004–2013. BMC Oral Health, 16(1), 21.

His claim relies on the comparison of data for “non-Māori” children in fluoridated and fluoridated areas. No – he doesn’t misrepresent the data – he just ignores the discussion by these authors of problems with simple interpretation of the data for non-Māori because of the fact it is not ethnically uniform. In particular, he ignores the qualifications they place on the data because of the inclusion in non-Māori of data for Pacifica who have poorer dental health than the rest of this group and live predominantly in fluoridated areas. This, in effect, distorts the data by overestimating the poor oral health for “non-Māori” in the fluoridated areas.

The apparent convergence

The data used in this study were taken from the Ministry of Health’s website. This divides the total population of children surveyed into the ethnic groups Māori, Pacific and “Other.” While the “other’ group will not be completely uniform (for example including Pakeha, Asian, other groups) it becomes far less uniform when combined with the Pacific group to form the non-Māori group.

So, Kane salivates over this figure from the paper especially the plots for  non-Māori ethnicities in fluoridated (F) and non-fluoridated (NF) areas.

12903_2016_180_Fig1_HTML

Fig. 1 No obvious decay experience (caries-free) percentages and mean dmft for 5-year old children over years 2004 to 2013, partitioned by Māori and non-Māori ethnicities and fluoridated (F) and non-fluoridated (NF) areas

Yes, that convergence is clear and I can see why Kane is clinging to it – who can blame him. But he completely ignores the warning from the paper:

“It is likely that a substantial driver of this convergence was due to significant changes within the dynamic and heterogeneous non-Māori groups both within and between DHB regions. In effect, the ecological fallacy – a logical flaw whereby analyses of group data are used to draw conclusions about an individual – may be operating within the non-Māori group.”

When the Pacific data is removed (as is the case for the “other” group effectively made up from non-Māori and non-Pacifica) we get the plots below.

Other

Comparison of data for “other” (non-Māori/non-Pacifica) children in fluoridated (F) and unfluoridated (UF) areas.

Nowhere near as useful for Kane’s confirmation bias and the message he wants to promote. OK – there is still some evidence of convergence from about 2007 on between fluoridated and unfluoridated children. But the graphs do show that community water fluoridation is still having  a beneficial effect. And this apparent convergence could be explained by things like the introduction of “hub and spoke” dental clinics after 2004. One problem with this raw data is that children are allocated according to the fluoridation status of the school – rather than their residence. This will lead to incorrect allocation in some cases.

Some data for Pacifica

Just to underline the problems introduced by inclusion of Pacific in the non-Māori group of the study consider the data for Pacifica shown below.

other-pacifica

Data for 5-year-old children. dmft = decayed, missing and filled teeth. The “other” group is non-Māori and non-Pacifica

The oral health of Pacifica is clearly poorer than that of the “other” group.

Also, Pacifica make up about 20% of the non-Māori fluoridated group. So they will influence the data for the non-Māori fluoridated group by reducing the % caries free and increasing the mean dmft.

So Kane, like Stan, is blatantly cherry-picking. He is misrepresenting the study – and its author – by ignoring (or covering up) the qualifications regarding the influence of inclusion of pacific in the non-Māori fluoridated group.

The challenge

Now, I repeat the offer I have made in the past to give a right of reply to both Kane Titchener and Stan Litras. They are welcome to comment here and if they want more space I am happy to give space for separate articles for them in the way I did for the debate with Paul Connett. Now I can’t be fairer than that, can I?

So what about it Stan and Kane? What are your responses to my criticisms of the way you have cherry-picked and misrepresented this New Zealand paper?


NOTE: I have sent emails to both Kane and Stan asking them to respond and offering them right of reply.

UPDATE 1: Great minds and all that – Stan Litras sent out a press release today calling for a nation-wide debate on this issue (see FIND calls for a national debate on fluoridation). However, the seriousness of his request is rather compromised by his reply to my offer of a right of reply to the above article. He did respond to my email very quickly. This is what he wrote:

“Thanks for the offer, Ken, but I have not visited your blog site for a long time, as I object to the way you attempt to defame and discredit me.

You play the man and not the ball, which is not the mark of a reasonable person.

I hope to address that in due course as time permits, but for now I must leave you to indulge yourself without my company.”

So much for his wish for a “national debate” when he will not front up to a critique of his claims about the science.

UPDATE 2: Kane Titchener today also posted a press release today which was the text of the article I discuss in this post (see NZ research proves fluoridation not needed). He also responded quickly to my e-mail. The full text of his response was:

Who is this?”

Rather strange – considering he often pesters me with emails.

So I guess both of them have turned down my offer.

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Cherry-picking and misinformation in Stan Litras’s anti-fluoride article

This is the second article in a series critiquing contributions to the Fluoride Free NZ report Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report.”

My first article Peer review of an anti-fluoride “peer review”  discussed Kathleen Theissen’s contribution. (It also discussed a draft contribution by Chris Neurath which does not appear in the final version).

I will shortly post a 3rd article discussing H. S. Micklem’s contribution.

See The farce of a “sciency” anti-fluoride report for an analysis of the close relationships between the authors and peer reviewers of the Fluoride Free report and anti-fluoride activist groups.


There is a lot in Stan Litras’s article to criticise – there is a lot which is misleading or outright wrong. I hope Stan will seriously consider my criticisms and respond to them, especially where he thinks I am wrong.

My criticisms should also be considered by Bruce Spittle and Hardy Limeback who Fluoride Free NZ listed as “peer reviewers” of Stan’s article. They must bear some responsibility for allowing the article to go ahead without the necessary corrections.

Litras makes many of his criticisms of community water fluoridation (CWF) in passing – without argument or evidence. But he declares:

“My comments will focus on the gross over statement of the purported benefits of fluoridation in our society, New Zealand, 2014.”

So, I will start with the claims he makes on this.

“Overseas studies” – The WHO data

Central to this are Stan’s assertions:

“The “elephant in the room” is that while decay rates fell in areas where fluoridation was implemented, it also fell in areas that weren’t, often at a faster rate. (8)”

And

“Globally, fluoridation is seen to make no difference to reduced decay rates, there being no difference between the few countries which use artificial fluoridation, and those that don’t. (8,7)”

His only evidence for this is a figure prepared by Chris Neurath from the Fluoride Action Network – using data from the World Health Organisation (WHO). Here it is in a slightly simpler version to the one used by Stan.

I am amazed that anti-fluoride propagandists keep using this graphic as “proof” that fluoride is ineffective. But they do – which can only mean they haven’t thought it through.

While the plots do show improvements in oral health for countries independent of fluoridation they say nothing about the effect of fluoride. Simple comparison of countries obscures all sorts of effects such as differences in culture, history, social and political policies, etc. Such plots are also influenced by changes and differences in dental treatment and measurement techniques.

Robyn Whyman in his report Does delayed tooth eruption negate the effect of water fluoridation? exposes the little trick Stan is trying to pull with the WHO data:

“Studies that appropriately compare the effectiveness of water fluoridation do not compare poorly controlled inter-country population samples. They generally compare age, sex, and where possible ethnicity matched groups from similar areas. Inter-country comparisons of health status, including oral health status, are notoriously difficult to interpret for cause and effect, because there are so many environmental, social and contextual differences that need to be considered.”

There are some within country data within the WHO data set Neurath used which can give a better idea of the beneficial effects of fluoridation. This plot shows the results for the WHO data for Ireland. A clear sign that fluoridation plays a beneficial role.

Neurath covered up evidence for the benefits of CWF by simply using the mean of fluoridated and unfluoridated areas for countries like Ireland and New Zealand. Also, the straight lines in Chris Neurath’s plots are a real give away to the poor quality of the data used. Two data points for each country!

New Zealand – Cherry-picking the MoH data

I have criticised Stan’s misrepresentation the Ministry of Health (MoH) data before. At the time he was using and misrepresenting some of my own graphics on his business website. He has since removed the offending article but now he returns with a vengeance – with tables and figures of his own.

This has given him free hand to cherry-pick and misrepresent to his heart’s content.

He claims:

“Ministry of Health figures recorded every year in 5 year olds and year 8s (12-13 year olds) consistently show minimal or no differences between fluoridated and nonfluoridated areas of NZ.”

stan_1

Cherry-picked data from Stan Litras

And he backs this up with a graph.

That looks about right. The data for 2011 shows 59.9% of 5 year olds in fluoridated areas were caries-free while 59.2% were carries free in non-fluoridated areas. No real difference.

But come on! A single data point, one year, one of the age groups for the fluoridated and unfluoridated areas! That is blatantly cherry-picking – as I mentioned in my article Cherry picking fluoridation data. In that I presented all the data for 5 year olds and year 8s, and for the total population and Maori, and for % caries free and decayed, missing and filled teeth (DMFT).

I have reproduced this data here in a simpler form using several figures.

caries-freeConsidering the % caries free data there are several points:

1: These do not “consistently show minimal or no differences between fluoridated and nonfluoridated areas” as Stan claims.

2. They do show a decline in differences between fluoridated and non-fluoridated areas in recent years.

3: This trend is less obvious for Maori but still present.

4: Stan has blatantly cherry-picked the  data points for 5 year-olds in 2011 to give him the least possible difference (see red circle in figure).

dmft

The data for decayed, missing and filled teeth (DMFT) shows similar trends.

Presumably both measures (% caries free and DMFT) are useful indicators of oral health but they probably convey complementary and not exactly the same information.

I discussed features of the graphs and their trends in in my articles Cherry picking fluoridation data and Fluoride debate: Response to Paul’s 5th article where I also discussed limitations in the data.

We need to appreciate this is just normal school clinic data, without technique standardisation for those making the measurements or proper recording of place of residence. The latter effect probably shows up more strongly after 2004 when a “hub and spoke” dental clinics system was introduced further confusing proper records of likely fluoride intake. One school dental clinic could serve a number of areas – both fluoridated and non-fluoridated. This mixing is a likely explanation for the apparent decline of the effectiveness of fluoridation after 2006.

So, yes, the MoH data is not straightforward. But this means it should be considered sensibly, taking into account its limitations and the social factors involved.  Instead, Stan has leapt in – found the data points which best fit his own biases and then tried to claim those data  are representative when they aren’t.

Stan presented another self-prepared graphic using data for the 4 different regions for 5 year olds (see his page 27). He appears not to have used the correct data – at least for the Northern and Southern regions.  My own graphic for this shows differences to his. (Of course, the mistake may be mine – if Stan can show I am wrong I will happily delete this part from my critique).

region-correct

Again, that data should also not just be considered at face value – or selected to confirm a bias. It has limitations. For example in this case there were only 55 children in the fluoridated Southern region compared with 7568 in the non-fluoridated area. A footnote on the data sheet says:

“2. Excludes Southern DHB because data were not reported for 1 Jan-20 Feb 2012, and fluoridation status was not captured for most children throughout 2012, due to transition to a new data system. “

Proper consideration of such data must take these sort of limitations into account. But of course all Stan Litras did was select data to support his assertions and ignore the rest. Any limitations in the data did not concern him.

Lifetime benefit

Stan has a thing about the “lifetime benefits,” or lack of benefits, of CWF. Most studies of CWF have used data for children – data for adults is less common but there is still research literature on this available.

But all Stan did on this was to cherry-pick a graphic (Figure 53) from the NZ Oral Health Survey showing no significant change in DMFT for 65-74 year olds between the years 1976, 1988 and 2009. He then claims:

“Data from the NZOHS 2010 do not support statements of a lifetime benefit, indicating that the action of fluoride is simply to delay the decay. (13)”

But he has had to work hard to avoid other data like that in Figure 49 below which do show a significant improvement in the number of retained teeth of that age group. The Oral Health Survey report itself says:

“In dentate adults aged 65–74 years, the mean number fell from 17.1 to 12.1 missing teeth per person on average from 1976 to 2009.”

mising-teeth

Again, instead of cherry-picking, searching for an image to fit his story, Stan should have considered the data and figures critically and intelligently. Perhaps the DMFT data does not show what he claims because more teeth have been retained in recent years. The decline in missing teeth could have been balanced by increases in fillings due to increase in remaining teeth. The lack of a significant difference in DMFT actually suggests the opposite to what he claims.

Litras also misrepresent the York review on the question of benefits from CWF for adults. He says:

“The York Review found there was no weight of evidence to support benefit in adults or in low SES groups, or increase of decay in cessation studies. (7)”

Just not true. The York report says:

“One study (Pot, 1974) found the proportion of adults with false teeth to be statistically significantly greater in the control (low-fluoride) area compared with the fluoridated area.”

Sheiham and James (2014) stressed that a proper assessment of oral health problems should include data for adults as well as children. Recent research is starting to take up this issue. For example O′Sullivan and O′Connell (2014) recently showed that water fluoridation provides a net health gain for older Irish adults.

Systemic vs topical

Stan promotes the common mythology of the anti-fluoridation propagandist that any mechanism for a beneficial effect of fluoride in restricting tooth decay is purely “topical.” He claims:

“It has been widely accepted since the 1990s that any effect on tooth decay from swallowing fluoride is insignificant or non-existent. To quote: CDC 1999: “the effect of Fluoride is topical “ (5); J Featherstone 1999: “the systemic effect is, unfortunately, insignificant” (6).”

Let’s consider what the sources Stan cites actually do say. I will quote from the 2001 edition of Stan’s citation 5 which he (partly) cites on page 36:

“Fluoride works to control early dental caries in several ways. Fluoride concentrated in plaque and saliva inhibits the demineralization of sound enamel and enhances the remineralization (i.e., recovery) of demineralized enamel (12,13 ). As cariogenic bacteria metabolize carbohydrates and produce acid, fluoride is released from dental plaque in response to lowered pH at the tooth-plaque interface (14 ). The released fluoride and the fluoride present in saliva are then taken up, along with calcium and phosphate, by demineralized enamel to establish an improved enamel crystal structure. This improved
structure is more acid resistant and contains more fluoride and less carbonate (12,15–19 ) (Figure 1). Fluoride is more readily taken up by demineralized enamel than by sound enamel (20 ). Cycles of demineralization and remineralization continue throughout the lifetime of the tooth.”

topical-mechanism

And

“Saliva is a major carrier of topical fluoride. The concentration of fluoride in ductal saliva, as it is secreted from salivary glands, is low — approximately 0.016 parts per million (ppm) in areas where drinking water is fluoridated and 0.006 ppm in nonfluoridated areas (27 ). This concentration of fluoride is not likely to affect cariogenic activity. However, drinking fluoridated water, brushing with fluoride toothpaste, or using other fluoride dental products can raise the concentration of fluoride in saliva present in the mouth 100-to 1,000-fold. The concentration returns to previous levels within 1–2 hours but, during this time, saliva serves as an important source of fluoride for concentration in plaque and for tooth remineralization (28 ).”

(Note: Stan simply quotes the first part of this statement (in red) in his article (page 36) and completely omits the second part (in black) – presumably because he wants to deny a role for fluoridated water in influencing the saliva fluoride concentrations. This cherry-picking of the CDC statement is typical for anti-fluoride propagandists – see Fluoridation – topical confusion).

There is an attempt to confuse a “topical” or “surface” mechanism with a “topical” application (eg toothpaste or dental treatments). However, fluoride is transferred to saliva from food and drink during ingestion so that ingested fluoride also contributes to the “topical” or “surface” mechanism.

However Stan wants to deny a “topical” role for ingested fluoride and claims (page 36):

“The required elevation of baseline levels only occurs after using fluoridated toothpaste or mouth rinse, a concentration of 1,000 ppm or more instead of 1 ppm from water.(24)”

His citation 24 is to Bruun (1984) and he misrepresents that paper which actually said:

“It was concluded that direct contact of the oral cavity with F in the drinking water is the most likely source of the elevated whole saliva fluoride and that the increased availability of fluoride in the oral fluids has an important relationship to the reduced caries progression observed in fluoridated areas.”

Systemic role.

Featherstone does say:

“Fluoride works primarily via topical mechanisms which include (1) inhibition of demineralization at the crystal surfaces inside the tooth, (2) enhancement of remineralization at the crystal surfaces (the resulting remineralized layer is very resistant to acid attack), and (3) inhibition of bacterial enzymes. Fluoride in drinking water and in fluoride-containing products reduces tooth decay via these mechanisms. Low but slightly elevated levels of fluoride in saliva and plaque provided from these sources help prevent and reverse caries by inhibiting demineralization and enhancing remineralization. The level of fluoride incorporated into dental mineral by systemic ingestion is insufficient to play a significant role in caries prevention. The effect of systemically ingested fluoride on caries is minimal.”

There is some debate over the role of systemic fluoride exuded by salivary glands. Many feel the concentration is too low – but because its effect is also determined by the presence of calcium, phosphate, organic species and pH it is best not to be dogmatic about this. It is, anyway, difficult to separate salivary fluoride derived from transfer from food and beverage in the oral cavity from that exuded by the salivary glands from systemic sources.

Stan is determined to deny a role for systemic fluoride during tooth development asserting:

“the erroneous theory that fluoride incorporated into children’s developing tooth enamel would make teeth more resistant to decay.”

While often neglected because of the concentration on surface mechanisms with existing teeth the theory that fluoride is incorporated into the developing teeth of children and confers a degree of protection is far from erroneous.

Newbrun (2004), for example, stressed in a review of the systemic role of fluoride and fluoridation on oral health:

“The role of systemic fluoride in caries prevention is neither “minimal” nor “of borderline significance.” On the contrary, it is a major factor in preventing pit and fissure caries, the most common site of tooth decay. Maximal caries-preventive effects of water fluoridation are achieved by exposure to optimal fluoride levels both pre- and posteruptively.”

Cho et al (2014) presented data showing that children exposed to CWF during teeth development retained an advantage over those never exposed to it even after fluoridation ceased.

Let’s stop confusing the issue. Systemic fluoride may not play a role with existing teeth but it does during tooth development – even if the relative contributions of systemic fluoride and “topical” or surface fluoride to lasting oral health are difficult to determine.

Tooth eruption delays

Stan resorts to special pleading when he claims with reference to NZ MoH data:

“Small apparent differences could be accounted for by other factors such as delayed eruption of teeth in fluoridated communities, therefore less time in the mouth exposed to plaque acids, ethnic distribution and urban/rural differences.”

He relies on the “York review” (McDonagh et al., 2000) to back up his “delayed tooth eruption” excuse:

“Importantly, the York Review noted that the variation of tooth eruption times between fluoridated and unfluoridated areas was not taken into account. (7)”

But that review actually said on this subject:

“It has been suggested that fluoridation may delay the eruption of teeth and thus caries incidence could be delayed as teeth would be exposed to decay for a shorter period of time. Only one study compared the number of erupted teeth per child. The difference was very small and in opposite directions in the two age groups examined, however no measure of the statistical significance of these differences was provided. Only one of the studies attempted to control for confounding factors using multivariate analysis (Maupomé 2000).”

Robyn Whyman has gone into this claim in more detail in his report Does delayed tooth eruption negate the effect of water fluoridation?Here he critiques Paul Connett’s reliance on this excuse and concludes from his review of the literature:

“The studies and reports cited by Professor Connett to try and validate an argument for delayed tooth eruption either do not make the claims he suggests, or do not have direct relevance to trying to assess the issue. The claimed association is at odds with the published literature which indicates minimal variation in eruption time of permanent teeth by exposure to fluoride. A rational explanation exists for the minimal variations that have been reported based on the relationship between fluoride exposure, caries experience in the primary teeth and emergence timing for the permanent teeth.”

The “delayed tooth eruption” excuse is nothing more than special pleading and straw clutching.

Socio-economic factors

Stan again misrepresented the York review regarding socio-economic effects on oral health and the effectiveness of CWF when he claimed “there was no weight of evidence to support benefit in adults or in low SES groups.” The York review actually said:

“Studies should also consider changes in social class structure over time. Only one included study addressed the positive effects of fluoridation in the adult population. Assessment of the long-term benefits of water fluoridation is needed.”

And

“Within the UK there is a strong social gradient associated with the prevalence of dental caries. This is found both in adults and in children. Those who are more deprived have significantly greater levels of disease. There is also geographical variation with the northwest of England, Scotland and Northern Ireland most severely affected. (Pitts, 1998; Kelly, 2000)”

There have been a range of studies internationally showing that fluoridation can aid in reducing differences in oral health due to socio-economic effects. See for example Cho, et al., (2014).

What happens when fluoridation is stopped

Stan briefly refers to this issue, citing (as anti-fluoridation activists always do) Künzel and·Fischer (2000). I will simply refer him, and interested readers to my article What happens when fluoridation is stopped? This boils down to the need to read the scientific literature properly as usually the anti-fluoridation activists ignore the details referring to fluoride treatments and procedures which replaced CWF.

There are a number of other points mentioned briefly by Stan Litras which could be discussed but this article is already too long so I will leave that to the comments section.

Conclusions

Stan Litras has simply indulged in blatant cherry-picking of data, and misrepresentation of the literature, in his critique of the recent review Health Effects of Water Fluoridation: a Review of the Scientific Evidence produced by the Royal Society of NZ together with the Office of the Prime Minister’s Chief Science Advisor. Perhaps we shouldn’t expect better from a political activist in the anti-fluoride movement but he, and Fluoride Free NZ, attempt to present this, and other articles in the collection, as objective and scientifically credible. It is neither – such cherry-picking and misrepresentation violates any scientific ethics and needs to be exposed for what it is. The Fluoride Free NZ claimed “peer reviewers,” Bruce Spittle and Hardy Limeback, must share responsibility because, by their endorsement, they signal their approval of such behaviour.

Note

I offered Stan Litras a right of reply to this post, or even an ongoing exchange with him along the lines of my debate with Paul Connett. He replied:

“I look forward to your comments on my review, as a lay person, but I cannot engage in a serious dialogue with someone who is not a peer with the same level of knowledge as myself in the dental field. “

Hopefully this means he will at least comment here, take issue with me where he thinks I am wrong and correct me where I am mistaken. I also hope than Bruce Spittle and Hardy Limeback will also take advantage of their right to comment here.

References

Bruun, C., & Thylstrup, A. (1984). Fluoride in Whole Saliva and Dental Caries Experience in Areas with High or Low Concentrations of Fluoride in the Drinking Water. Caries Research, 18(5), 450–456.

Centers for Disease Control and Prevention. (2001). Recommendations for Using Fluoride to Prevent and Control Dental Caries in the United States (Vol. 50, p. 50).

Cho, H.-J., Jin, B.-H., Park, D.-Y., Jung, S.-H., Lee, H.-S., Paik, D.-I., & Bae, K.-H. (2014). Systemic effect of water fluoridation on dental caries prevalence. Community Dentistry and Oral Epidemiology.

Cho, H.-J., Lee, H.-S., Paik, D.-I., & Bae, K.-H. (2014). Association of dental caries with socioeconomic status in relation to different water fluoridation levels. Community Dentistry and Oral Epidemiology.

Fluoride Free New Zealand. (2014). Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report.

Künzel, W.;·Fischer, T. (2000). Caries Prevalence after Cessation of Water Fluoridation in La Salud, Cuba. Caries Res, 34, 20–25. Retrieved from http://www.karger.com/Article/Fulltext/16565

McDonagh, M., Whiting, P., Bradley, M., Cooper, J., Sutton, A., & Chestnutt, I. (2000). A Systematic Review of Public Water Fluoridation.

Ministry of Health. (2010). Our Oral Health Key findings of the 2009 New Zealand Oral Health Survey. Wellington, Ministry of Health.

Ministry of Health (2014) Age 5 and Year 8 oral health data from the Community Oral Health Service. http://www.health.govt.nz/nz-health-statistics/health-statistics-and-data-sets/oral-health-data-and-stats/age-5-and-year-8-oral-health-data-community-oral-health-service.

National Fluoridation Information Service (2011): Does Delayed Tooth
Eruption Negate The Effect of Water Fluoridation? National Fluoridation Information Service Advisory June 2011, Wellington, New Zealand.

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