Tag Archives: tooth decay

Fluoridation: Another study shows stopping fluoridation bad for child tooth decay

Stopping community water fluoridation in Alaska’s capital city, Juneau, caused an increase in child tooth decay

In the last week, Windsor in Ontario, Canada, voted to reinstate community water fluoridation (CWF) 5 years after it was stopped because of opposition. This time the City Council was swayed by the Windsor-Essex County Health Unit’s Oral Health 2018 Report which found the percentage of children with tooth decay or requiring urgent care increased by 51 per cent since fluoridation had stopped.

Now a new study reports similar increases in child tooth decay after stopping CWF in the Alaskan capital, Juneau. This paper reports the study results for Juneau:

Meyer, J., Maragaritis, V., & Mendelshon, A. (2018). Consequences of community water fluoridation cessation for Medicaid-eligible children and adolescents in Juneau, Alaska. BMC Oral Health, 18:215

Juneau – an ideal community for the study

Juneau maintains all the modern conveniences and standards expected of a capital city but has little in-and-out migration or travel from neighboring countries as it is accessible only by plane or sea. This reduces confounding effects due to population changes, only about 0.006% per year during the study period.

Use of fluoridated toothpaste is widespread and CWF was available to 96% of residents before it was stopped in January 2007.

The researchers compared child oral health data in 2003 (when children were exposed to optimum levels of fluoride: 0.7 – 1.2 mg/L) with that in 2012, 6 years after CWF ceased. During those six years, exposure to fluoride was suboptimum: <0.065 mg/L.

The data used for the study was from Medicaid dental claims records. This means the study population was made up of residents living at near poverty conditions. This limited confounding effects from higher-income groups.

Cessation of CWF resulted in increased child tooth decay

The findings were clear and statistically significant. The number of caries-related dental procedures increased after cessation of CWF.

For all children and adolescents (ages 0 – 18 years) the number of procedures increased by 16%. But binary logistic results indicated “the odds of a child or adolescent undergoing a dental caries procedure in 2003 was 25.2% less than that of a child or adolescent in the suboptimal CWF group.”

The effects of CWF were even greater for children aged 0 – 6 years who had never experienced the advantages of exposure optimum fluoride levels. The number of caries-related dental procedures in this group increased by 63%. However,  binary logistic results indicated “the odds of undergoing dental caries procedures under optimal CWF conditions was 51% less than that for a child of the same age in 2012 under suboptimal conditions.”

CWF cessation increased dental treatment costs

The researchers obtained dental costs from the Medicaid dental claims records so were able to make estimates of the effects of CWF on the financial costs to the community. After adjusting for inflation this data showed that the increased annual cost per person of ages 0 – 18 years due toi cessation of CWF increased by $162, a 47% increase. The corresponding increase for children 0 – 6 years was %303, a 111% increase.


While this study had several advantages over similar studies because of reduced confounding effects due to migration and socioeconomic factors this may also be seen as a limitation when trying o extend to findings to more socially heterogeneous communities. However the authors conclude it does provide stong evidence supporting:

“current evidence that even in modern conditions with widely available fluoride toothpaste, rinses, and professionally applied prophylaxis, CWF is associated with population benefits, including cost effectiveness and caries prevention.”

They also conclude from their results that:

“CWF cessation promoted a marked increase in the number of caries-related procedures and treatment costs for Medicaid-eligible children and adolescents aged 0–18 years. Additionally, the results indicated that children in the younger age group cohorts underwent more dental caries procedures than the older age group cohorts, who had benefited from early childhood exposure to optimal CWF.”

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New research confirms adults benefit from community water fluoridation as well as children


Community water fluoridation is beneficial to adults as well as children.

A new Australian study confirms that lifetime access to community water fluoridation (CWF) is associated with reduced tooth decay for adults – at least in the age groups 15 – 34 years and 35 – 44 years.

The study is reported in the paper:

Do et al., (2017). Effectiveness of water fluoridation in the prevention of dental caries across adult age groups. Community Dentistry and Oral Epidemiology.

Other workers reported similar results. But Do et al., (2017) had a closer look at the data, because of the difficulties in assessing both access to CWF, and tooth decay, in adults. In particular, they carried out a secondary analysis which looked at lifetime access to CWF and tooth decay within defined age groups as well as across age groups of adults aged between 15 – 91 years.

They found the association of access to CWF with reduced tooth decay was strongest for the youngest adult age group, 15 – 34-year-olds.  The association was weaker, but still significant, for the 35 – 44 years age group. However, they did not see a significant association for the remaining age groups, 45 – 54 years and 55+ years.

The authors discuss possible reasons for what they call the “fading” of apparent benefits from CWF with age.

1: Lack of exposure to CWF during childhood for the older age groups. This is because CWF was not present when they were young. The authors say:

“there is some evidence among children at least of the importance of a critical period of exposure, where either the incorporation of fluoride into the developing tooth may be crucial or the establishment of a positive mouth ecology may set a child on a lifelong trajectory.”

This would be in line with research showing a systemic effect of fluoride for developing teeth in children. There is also that those older adults were exposed to risks of tooth decay before later being exposed to CWF.

2: A limit to the measurement of tooth decay in adults because the measures of tooth decay:

“increasingly shows saturation of all susceptible surfaces, whereby more members of an age group approach a ceiling in the sum of the surfaces with past or present caries experience. . . .  It should be emphasized that, for the older age groups, this saturation might have occurred before access to FW had become available in Australia.”

So, yet another confirmation of the benefits of CWF for adults as well as children.

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Do you prefer dental fluorosis or tooth decay?

Anti-fluoride propagandists often use the incidence of dental fluorosis as an argument against community water fluoridation. However, they exaggerate the problem by misrepresenting the issue in two ways:

1: They present the issue as if the figures for the incidence of dental fluorosis relate to the severe forms when they don’t. Most cases of dental fluorosis in areas using CWF are classified as questionable or mild. Yet the anti-fluoride people will present images of severe dental fluorosis which is never caused by CWF (see ). Severe forms are caused by excessive toothpaste consumption, high natural fluoride levels or industrial contamination. Never by CWF.

The figure below shows the incidence of the different dental fluorosis categories in New Zealand (data taken from 2009 New Zealand Oral health Survey – see Our Oral Health).

And here are some accurate images of dental fluorosis provided by the Centers for Disease Control and Prevention (CDC).


 (Double click to enlarge)

2: They will then go on to claim that dental fluorosis is disfiguring and destroys the quality of life of the afflicted. Of course this may be true in countries where severe dental fluorosis occurs,* but not in countries like New Zealand where CWF is used.

A recently published study objectively determined the effect of dental fluorosis and dental decay on 5,474 North Carolina schoolchildren and their families – Effects of Enamel Fluorosis and Dental Caries on Quality of Life. It found no statistically significant association between dental fluorosis and oral-health related quality of life scores. Probably what one would expect because the incidence of dental fluorosis was about 28% and most of this was questionable or very mild.

But what about the effect of tooth decay on quality of life? In this case the results were statistically significant showing that dental caries does decrease the quality of life.

Their overall conclusions – a child’s caries experience negatively affects oral health-related quality of life, while fluorosis has little impact.

I think many of us can relate to this from our own childhood experience.

*The mainly poor quality IQ studies anti-fluoridation activists like Paul Connett love to quote were made in areas of high natural fluoride where dental and skeletal fluorosis is endemic. Such studies are not relevant to the issue of CWF, but they do raise in my mind the effect of severe dental fluorosis on quality of life, learning problems and hence possibly IQ measurements (see my article Confirmation blindness on the fluoride-IQ issue). Personally I think any disfiguring oral defect like bad tooth decay or severe dental fluorosis would effect a child’s quality of life and potentially cause learning defects and so drop in IQ.

In countries like NZ such effects on quality of life and learning are much more likely to result from bad dental decay than severe dental fluorosis. If anything, perhaps CWF actually reduces learning problems and potentially prevents decreases in IQ.


Another study invesdtigatign the influence of tooth decay and dental fluorsis on quality of life is described in the paper by Do, L. G., & Spencer, A. (2007). Oral Health-Related Quality of Life of Children by Dental Caries and Fluorosis Experience. Journal of Public Health Dentistry, 67(3), 132–139.

This also concluded that caries and less acceptable appearance showed a negative impact, while mild fluorosis had a positive impact on child and parental perception of oral health-related quality of life.

See also:

New report from the National Fluoridation Information Service – Dental fluorosis – is it more than an aesthetic concern? Its key findings are:

“Evidence does not indicate there are any health risks associated with CWF at the levels of 0.7 to 1.0 mg/L in New Zealand, and no severe dental fluorosis, or skeletal fluorosis, has been found. While fluoride is incorporated into teeth and bones, there is no robust evidence of toxic accumulation of fluoride in other tissues in the body. CWF in New Zealand has been found to not lead to anything more than very mild or mild dental fluorosis for a small “

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