What scientists say on fluoridation
Expert Q
12 June 2017
As parliament considers a bill to put decision-making about community water fluoridation in the hands of district health
boards, fluoridation is likely to remain a polarising issue for some communities.
The SMC asked New Zealand and international experts to discuss what the science says about the benefits of fluoridation
and what communities should consider when debating fluoridation in their water supply.
These are excerpted comments, the full Q is available on scimex.org for registered journalists. Feel free to use these comments in your reporting.
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Dr Robin Whyman, Clinical Director Oral Health, Hawke's Bay District Health Board
NZ's fluoridation is decided on a region-by-region basis - is there any evidence for differences between health outcomes
in fluoridated vs non-fluoridated regions?
"A number of studies have examined the differences in dental caries (dental decay) between children living in
fluoridated and non-fluoridated area of New Zealand.
"A study published in 2004 reported the severity of dental decay of children aged 5 years and 12 years in Wellington
(fluoridated) and Canterbury (non-fluoridated). In 5-year-old children dental decay severity was 30% lower, and in
12-year-old children 40% lower, in fluoridated Wellington than in non-fluoridated Canterbury children, after controlling
for confounding factors.
"In 2005 a study of Southland children living in Invercargill, Gore, Winton and Queenstown reported that children aged 9
and 10 years living in fluoridated areas had half the severity of dental decay of those living in non-fluoridated areas,
again after controlling for confounding factors.
"In 2009 an Auckland study of 9-year-old children found those living all of their lives in fluoridated areas were under
half as likely to have dental caries as those living none of their lives in fluoridated areas.
"In 2009 New Zealand conducted a national oral health survey of children and adolescents and reported that those living
in areas with fluoridated water had a 40% lower incidence of dental decay.
"The evidence regarding the effect of fluoridation on oral health for children and adolescents in NZ is summarised in a
report for the NZ Ministry of Health by the Sapere Research Group entitled Review of the benefits and costs of fluoridation in New Zealand and published in 2015."
Fluoridation has become a highly-charged debate, where does this opposition stem from?
"Opposition to fluoridation focuses on a lack of acceptance of the science. Opponents question the benefits to oral
health, and frequently do not accept that science does not support purported health risks.
"Opposition also focuses on the question of the legalities of fluoridation and suggests that community water
fluoridation is unethical because it is suggested to constitute a form of mass medication."
How should DHBs or local government balance the public health benefits of fluoridation against the perceived issues
raised by opponents?
"District Health Boards (DHBs) or local government should seek the advice of the scientists, medical and dental
professionals with expertise in public health issues and fluoridation.
"DHBs and local governments should weigh statements against fluoridation with the information about the benefits to oral
health for communities, especially children and people who are at greatest risk of dental decay.
"A public health approach to considering these issues requires careful consideration of the benefits to people who are
the most vulnerable, or unable to express strong opinions themselves."
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Associate Professor Jonathan Broadbent, preventative and restorative dentistry, University of Otago
What are the main arguments against fluoridation and where does the evidence stand on these points?
“Epidemiological research can't absolutely prove that there is no possibility of harm from something like fluoridation.
Epidemiological research can give us good confidence that it does not cause harm, but not with 100% certainty.
“The precautionary principle suggests that we don't do something 'just in case it causes harm'. However, applying this
inappropriately can be counter-productive. I would argue that the known benefits of fluoridation in reducing the impact
of such a prevalent disease as tooth decay, outweighs the hypothetical harms.”
What would you say to people who are confused or concerned by the debate around community water fluoridation?
“Fluoride is in water anyway - all that is done in fluoridation is an adjustment of the levels. In NZ the
naturally-occurring fluoride levels are low, in other countries they are too high. It is important that fluoride levels
be controlled so that they are 'just right'.
“Fluoridation has been around for a long time. Fluoride toothpaste and fluoridated water are an important part of the
reason that young New Zealander's teeth are now much better than they were in previous generations.
“Fluoride is only part of the equation for improving dental health - we need to keep the pressure on for control of
added sugars in foods and drinks. We also need to find ways to make dental care more accessible to people, as so many
New Zealanders find dental care to be unaffordable.”
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Representatives from The US Centers for Disease Control and Prevention (CDC)
The majority of US citizens drink fluoridated water - is there any evidence of differences in health outcomes between
fluoridated and non-fluoridated regions?
"Evidence from the Guide to Community Preventative Services shows that water fluoridation prevents tooth decay by providing frequent and consistent contact with low levels of
fluoride, ultimately reducing tooth decay by 25% in children and adults.
"Additional evidence shows that schoolchildren living in communities where water is fluoridated have, on average, 2.25
fewer decayed teeth compared to similar children not living in fluoridated communities."
What would you say to people who are confused or concerned by the debate around community water fluoridation?
"Community water fluoridation is one of the most practical, cost-effective, equitable and safe measures communities can
take to prevent tooth decay and improve their oral health.
"Water fluoridation benefits people of all ages and socioeconomic groups, including those difficult to reach through
traditional public health programs and private dental care. In fact, each generation born since the implementation of
water fluoridation has enjoyed better dental health than the generation that preceded it.
"In addition, community water fluoridation saves communities money by avoiding the cost of dental treatment by
protecting teeth. Communities of all sizes that support water fluoridation see a positive return on investment (ROI) by
avoiding costs of dental treatment."
The full Expert Q and related resources are available on scimex.org.