Potential effects of water fluoride on teeth
To reduce tooth decay, the Kāpiti Coast District Council adds fluoride to water supplied to the Waikanae, Pararparaumu and Raumati supply zones. Fluoride is not added to the Ōtaki and Paekākāriki water supplies.
Water supply sources often contain naturally occurring levels of fluoride. Naturally occurring fluoride levels in Kāpiti Coast District Council’s raw water supplies are:
These naturally occurring fluoride levels are too low for teeth protection.
The Ministry of Health (MoH) recommends that for oral health reasons, the fluoride content for drinking-water in New Zealand should be in the range of 0.7 mg/L to 1.0 mg/L. This recommended dosing range is based on advice from the World Health Organisation (WHO).
Kāpiti Coast District Council has reduced the level of fluoride within the Waikanae, Paraparaumu and Raumati supply zones from 1.0mg/L to 0.7 mg/L. A copy of the council report is available below:
- Water Fluoridation Levels (AS-10-989) (PDF, 9 pages, 118Kb)
Non-fluoridated water is available at public supply points located within Ōtaki and Paekākāriki:
- Ōtaki Visitor Centre
- Paekākāriki Town Centre
Bottled water that is labeled purified, demineralised, deionised, distilled or reverse osmosis filtered, should also be free of fluoride or have low levels.
Boiling water does not reduce the fluoride content. If anything it will increase the concentration in the water.
Children under six years drinking fluoridated water
A recent report from the European Commission (May 2010) has highlighted scenarios outlined in a number of research reports that show children under six years drinking fluoridated water could receive more than the recommended dose of fluoride for their age and weight. This may also occur for infants receiving formula made up with fluoridated water. The intake of too much fluoride by a young child could cause moderate dental fluorosis in some teeth. This is damage to the tooth enamel where the enamel surfaces of the teeth show marked wear and brown stains frequently disfigure the teeth.
In 2009 Food Standards Australia New Zealand reviewed the issues around dietary fluoride intake in depth. They found that although there is a theoretical potential for a young child to ingest too much fluoride, in reality there is not a risk to health in Australia and New Zealand. Moderate dental fluorosis is very rare in Australia and New Zealand and the levels of it do not differ between fluoridated and non-fluoridated children. Dr Erin Mahoney is the only specialist paediatric dentist in the Wellington region and has undertaken PhD research into tooth enamel defects. Dr Mahoney confirms that both recent research and her clinical experience show that moderate dental fluorosis is very rarely seen.
However reports, such as that from the European Commission, show that the potential risk of moderate fluorosis can be significantly reduced if the level of fluoride in water is reduced to the lower end of the Ministry of Health’s current recommended range of 0.7 mg/L to 1.0 mg/L. This is a practical way to ease any concern. This potential issue must be balanced against the known effect of reducing dental decay in natural teeth.
Further information on water fluoride can be found on the websites below:
- Ministry of Health
- Food Standards Australia New Zealand
- Scientific Committee on Health and Environmental Risks (SCHER), European Commission
Information pamphlets are also available from Regional Public Health, telephone 04 570 9002