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Fluoride is a natural substance that helps protect our teeth by making them stronger, and reducing tooth decay. It exists naturally in air, soil, fresh water, sea water, plants and in lots of food.

Source: Manatū Hauora | Ministry of Health – Fluoride and Oral Health - www.health.govt.nz/our-work/preventative-health-wellness/fluoride-and-oral-health, available under the Creative Commons Attribution 4.0 International Licence.

Water fluoridation is the process of adjusting the natural level of fluoride in the water supply to between 0.7 ppm and 1.0 ppm. This is the optimal amount that provides protection against tooth decay, and is recommended by the World Health Organization.

The current level of fluoride found in untreated water supplies in New Zealand is not effective enough to be of benefit in helping to prevent tooth decay, so ‘topping up’ the fluoride levels in reticulated water supplies has been done in many regions around New Zealand over several decades. The amount added is monitored to make sure that the levels stay within that range.

Along with brushing twice a day, eating healthy foods and timely check-ups with a dental provider, water fluoridation is a proven public health measure to reduce tooth decay. The World Health Organization and other international and national health and scientific experts endorse water fluoridation as the most effective public health measure for the prevention of dental decay. The role of fluoride in water has been examined in many locations and in many countries, including New Zealand, over the last 60 years.

Fluoride works in three ways to help protect our teeth from decay:

1. Fluoride makes teeth more resistant to decay by strengthening the tooth surface
2. Fluoride interferes with the growth of the bacteria which cause cavities
3. Fluoride helps to repair the early stages of tooth decay.

Eating and drinking increases the acidity in the mouth – this can remove the minerals from teeth, leading to tooth decay. Drinking fluoridated water and brushing teeth with fluoride toothpaste increases the concentration of fluoride in saliva and plaque fluid. Fluoride in water acts like a constant repair kit that neutralises the effect of acids that cause decay and helps to repair damage before it becomes permanent.

Source: Manatū Hauora | Ministry of Health – Flouride and Oral Health - www.health.govt.nz/our-work/preventative-health-wellness/fluoride-and-oral-health, available under the Creative Commons Attribution 4.0 International Licence.

Community Water Fluoridation is an effective, safe and affordable way to prevent and reduce tooth decay for everyone.

Along with brushing teeth twice a day, eating healthy food and avoiding sugary drinks, water fluoridation helps to prevent tooth decay.

Over half of children, and over a third of adults, don’t brush twice daily with the recommended fluoride toothpaste – so water fluoridation is particularly important. (Ministry of Health’s NZ Oral Health Survey 2009)

It’s effective

Over 60 years of international and New Zealand studies show that children and adults living in areas with water fluoridation have significantly less tooth decay than those living in non-fluoridated areas.

The NZ Oral Health Survey 2009 shows that on average New Zealand children have 40% less decay experience (ie, decayed, missing or filled teeth) in areas with fluoridation than in areas without it.

It’s safe

Overwhelming evidence from decades of having Community Water Fluoridation is that it is safe. ‘It is absolutely clear that at doses used in New Zealand to adjust the natural level to one that is consistent with beneficial effects (0.7–1.0ppm), there is no risk from fluoride in the water.’ Professor Sir Peter Gluckman, Chief Science Advisor, Office of the Prime Minister's Science Advisory Committee.

It’s affordable

There is strong evidence that community water fluoridation is cost-effective – saving much more in dental costs for individuals than it costs to run fluoridation programmes:

• Cost of fluoridation approx. $2.60 per person per year (Sapere Research Group, 2015)
• $250: Average cost of a single filling for an adult (Sapere Research Group, 2015)

For every dollar that is spent on water fluoridation, $9 are saved in dental care costs. Some of these savings are seen by the health system, but it is mostly individual New Zealanders who benefit – paying for fewer fillings and tooth extractions. (Sapere Research Group, 2015).

Source: Manatū Hauora | Ministry of Health – Fluoride Facts - www.health.govt.nz/your-health/healthy-living/teeth-and-gums/fluoride/fluoride-facts, available under the Creative Commons Attribution 4.0 International Licence.

How much difference does having the fluoride in water topped up make?

A lot. There is significant evidence from over 60 years that confirms that water fluoridation at recommended levels prevents dental decay.

New Zealand's most recent national oral health survey shows on average 40% less tooth decay experience for children in fluoridated areas than in those areas without it (New Zealand Oral Health Survey, Ministry of Health, 2009). The Australian National Survey of Adult Oral Health (2013) showed that adults experience 20–30% less tooth decay.

Many other international studies, and regional studies within New Zealand, have shown that children and adults living in areas with community water fluoridation have significantly lower tooth decay than people living in areas without it.

How do we know if it’s safe?

Fluoride already exists in water. It is topped up to levels that provide a benefit to teeth. At these carefully monitored levels, fluoride is safe and within the guidelines of the World Health Organization and other international public health agencies.

‘It is absolutely clear that at doses used in New Zealand to adjust the natural level to one that is consistent with beneficial effects (0.7–1.0 ppm), there is no risk from fluoride in the water.’
– Professor Sir Peter Gluckman, Chief Science Advisor, Office of the Prime Minister’s Science Advisory Committee.

In August 2014, the Royal Society of New Zealand and the Office of the Prime Minister's Chief Science Advisor jointly published the report Health Effects of Water Fluoridation: A Review of the Scientific Evidence. This report found that community water fluoridation within the range of concentrations currently recommended by the Ministry of Health and used in New Zealand poses no health risks, and the report also confirmed that there is compelling evidence of dental health benefits for New Zealanders.

Are there any known side-effects to community water fluoridation?

The only known side-effect of fluoridation at levels used in New Zealand is mild dental fluorosis, and it makes the teeth look whiter than normal enamel. It is visible to dental health professionals under close examination, and recent evidence from Australia indicates that this fades with time. There are no reported cases of disfiguring fluorosis associated with the fluoridating of water supplies in New Zealand.

The Ministry of Health’s New Zealand Oral Health Survey 2009 notes, ‘no significant differences in the prevalence of fluorosis...between people living in fluoridated areas and those in non-fluoridated areas’.

‘One side-effect of fluoride is for a portion of the population it causes minimal white mottling of the enamel...This is very rarely discernible and is definitely not the severe fluorosis that is so often pictured on websites of those opposed to fluoridation of the public water supply’
– Professor Sir Peter Gluckman, Chief Science Advisor, Office of the Prime Minister’s Science Advisory Committee

If people brushed their teeth would it mean we don't need water fluoridation?

Keeping your teeth healthy also requires brushing twice a day with fluoride toothpaste, dental care and reducing sugar. Community water fluoridation provides additional benefits even if you do all these things. Over half of New Zealand adults avoid going to the dentist because of cost, and over half of New Zealand children don’t brush their teeth twice a day with the recommended strength fluoride toothpaste.

That’s why community water fluoridation is so important – it makes good oral health accessible to all.

If it’s so good for you why do people oppose it?

There are different reasons why people oppose water fluoridation. These may include health concerns, not being aware of the benefits and wanting individual choice.

Communities can be confident that community water fluoridation is an effective and safe option. There is strong international evidence that there are no adverse effects of any significance arising from fluoridation at the levels used in New Zealand.

What do other countries do?

The World Health Organization recommends boosting fluoride to optimum levels and community water fluoridation as the best method to do this. Use of community water fluoridation in Australia and the USA has expanded. In some countries in Europe, the practicalities in adding fluoride to the water supply, mean that alternative methods are used to boost fluoride to optimal health levels – such as adding fluoride to salt or milk.

Source: Manatū Hauora | Ministry of Health – Questions and Answers - Fluoride - www.health.govt.nz/your-health/healthy-living/teeth-and-gums/fluoride/fluoride-facts/questions-and-answers-fluoride, available under the Creative Commons Attribution 4.0 International Licence.