Water Fluoridation - Question and Answers

Fluoridation of the public piped water supplies is the safest, most effective and most efficient method of preventing tooth decay. By controlling the quality and the amounts of fluoride in the public water supply through technical means and under legal rules, the safety of everybody in the community is assured.

Over the past 30 years, the incidence of dental decay has declined considerably in Ireland and in other developed regions of the world. A major public health advance has been achieved. Most scientists agree that the reason for the improvement is fluoridation of public water supplies and the increased use of other fluoride products.

Water fluoridation is a low cost public health measure which is safe to human health and crosses social boundaries providing benefits equally to all sections of society, including both young and old and socially deprived.

Minor aesthetic effects result from excess fluoride exposure from all sources. These effects can be minimised by ensuring that fluoride levels are monitored carefully and kept within the statutory limit of 0.8 to 1.0 part per million and by ensuring that young children use toothpaste sparingly under the supervision of parents/carers.

Ongoing research being carried out in University College Cork and in Trinity College Dublin on behalf of the eight regional Health Boards and the Department of Health and Children will inform policy on the most appropriate use of fluoride for the future.

A Forum has been established by the Department of Health and Children which will review this research as well as the fluoridation of the public water supplies under the Health (Fluoridation of Water Supplies) Act 1960, (see their website at www.fluoridationforum.ie).

Why was water fluoridation introduced in Ireland?
The widespread availability of refined sugars in the mid 19th century led to an epidemic of dental disease (which has only recently come under control). To reduce levels of dental decay, the Irish Government in the 1960s decided to fluoridate public water supplies.

What are the effects of water fluoridation on general health?
Major reviews of the evidence by leading medical scientists have shown that the use of fluoride in drinking water at one part per million is safe to human health.

The Department of Health and Human Services in the United States carried out a comprehensive review of the benefits and potential health risks of fluoride and concluded that the practice of fluoridating community water supplies is safe and effective. The review found that there is no credible evidence linking the fluoridation of water at one part per million with cancer, kidney disease, immune defects, reproductive problems, genotoxicity, stomach ailments and bone fractures.

The World Health Organisation, The Centres for Disease Control and Prevention in Atlanta, USA, The Royal College of Physicians London, The Royal College of Physicians of Ireland, and many other authoritative bodies support these findings.

In countries with unusually high levels of fluoride at ten parts per million or higher in drinking water, skeletal fluorosis is a significant public health problem.

What about the allegations being made against water fluoridation?
Allegations have been made against water fluoridation since it was introduced in Ireland in the 60s.

The current debate is only taking place here after almost 40 years of water fluoridation.

Similar debates have taken place in other countries that have adopted water fluoridation, for example, the United States, Canada, Australia, New Zealand and the United Kingdom - countries which have decided to retain their water fluoridation programmes.

Much of the present debate seems to have spilled over from the debate in the United Kingdom where the authorities are making preparations to extend water fluoridation to other regions in the United Kingdom.

What are the side effects of water fluoridation?
A side effect of water fluoridation is dental fluorosis. However, the type of fluorosis produced by water fluoridation at one part per million is almost undetectable to the untrained eye.

More severe forms of fluorosis are most definitely caused by young children swallowing too much fluoride toothpaste.

Children under six years of age should be supervised when brushing and should only use a small pea-sized amount of toothpaste. All parents should be aware of this.

How does fluoride prevent tooth decay?
Fluoride in the diet through fluoridated tap water ensures a constant optimal level of fluoride in the body. This enhanced, beneficial fluoride level in the saliva ensures the greatest resistance of teeth to decay.

The levels of fluoride in saliva are very low (about 0.02 part per million fluoride in saliva) even in people who drink fluoridated drinking water. People who do not drink fluoridated water have only about half that amount of fluoride in their saliva thus making their teeth much less resistant to acid attack and therefore to tooth decay.

Fluoride, particularly in drinking water, is largely responsible for the enormous reduction in tooth decay in recent years. The dramatic fall in levels of tooth decay has led to a great improvement in dental health for everyone who consumes fluoridated drinking water.

What have been the effects of water fluoridation on oral health?
The introduction of water fluoridation in Ireland nearly 40 years ago is largely responsible for the 70% falls in levels of tooth decay. Dental health surveys carried out by the state in 1963, 1984, 1989 and 1990 confirm that water fluoridation has had a major impact on the oral health of Irish children and adults.

Dental decay has also declined in areas and countries where there is no water fluoridation, the main reason being the widespread availability of fluoridated toothpastes. However, in areas where the level of risk is high with high frequency consumption of sweets and confectionery, the use of fluoridated toothpastes alone is insufficient to prevent dental decay.

A recent survey of adolescent snacking patterns in 19 European countries revealed that Irish and Scottish children were worst. In 1992, a study comparing the decay levels of 12 years old children in Dublin and Glasgow showed the level of decay was 45% lower in Dublin which is fluoridated compared to Glasgow which is non fluoridated. This is a good indication of the additional benefit provided by water fluoridation when other risk factors are similar.

A recent publication comparing the decay levels for 5 - 7 years old children in 23 countries in Europe shows that Ireland has the lowest level of decay for this age group.

Do we still need water fluoridation?
The level of risk in the Irish population for dental decay is still very high. Along with Scotland, Ireland is the worst of 17 European countries for the amount of sweets and confectionery being consumed by children and adolescents.

Water fluoridation is the most effective population strategy to counter this threat as it reaches the whole population, benefits all age groups and does not rely on compliance.

Is fluoride toothpaste use not sufficient enough to ensure good oral health?
Fluoride toothpaste is helpful but not as effective as water fluoridation. Also less than 50% of Ireland's adolescent boys are brushing more than once a day with fluoride toothpaste. This is insufficient to protect against tooth decay.

Are we getting too much fluoride?
The question we should ask is are we getting the right amount of fluoride?
A contract has been placed with the Oral Services Research Centre in University College Cork on behalf of the Department of Health and Children and the health boards to investigate all aspects of fluoride use and intake including water fluoridation, fluoride toothpaste, fluoride mouthrinses and fluoride tablets.
The outcomes of the project will produce specific guidelines and recommendations on/for fluoride use in Ireland which will ensure that the population gets the best possible benefits while at the same time minimising any possible disadvantages such as dental fluorosis.

Why is Ireland the only democracy with a mandatory national water fluoridation programme?
There are 40 countries worldwide with national fluoridation programmes. Each uses a legal instrument, which is appropriate to their own individual circumstances.

The reason why Ireland chose a mandatory programme, has its origins in the debate which took place in the Dail at the time fluoridation was introduced here. The Minister for Health at the time took the view after hearing the arguments of the anti-fluoridationists that they would cause confusion in the country if he proceeded with enabling legislation.

The councillors of each local authority would have to debate the issue without having the expertise that was available to the Dail to counteract the arguments being put forward by the anti-fluoridationists. At a practical level there would be serious problems with various local authorities coming to different decisions while sharing the same water supplies.

This is similar to what happened in more recent times in the Netherlands.

What processes took place to enable the introduction of water fluoridation in Ireland?
The introduction of water fluoridation commenced in Ireland in 1964. Several years prior to this were spent in public consultation, a scientific review and a subsequent report by an expert body (the Fluorine Consultative Council) were also carried out. Legal and constitutional cases taken to the High Court and finally the Supreme Court followed debates in the cabinet, Dail and Seanad.

In all of these processes the normal scientific, democratic, legal and constitutional methods were followed and, in each, the safety, desirability and necessity for public water fluoridation was upheld.

Where else in the world is water fluoridation carried out?
The World Health Organisation estimates that approximately 210 million people in 39 countries benefit from artificially fluoridated water. An additional 40 million benefit from water supply which is naturally fluoridated.

Community water fluoridation schemes have been in existence in the United States for over 55 years and are employed in 40 countries throughout the world including Spain, Switzerland, Australia, Canada, the United Kingdom, Israel, Singapore and New Zealand.

Currently about 60% of the population in the United States and 65% of Australians drink fluoridated water.

In the United States, 42 out of 50 of the largest cities, including New York, Washington DC, Chicago, Boston, Philadelphia and San Francisco have fluoridated water supplies.

In South Africa, a national water fluoridation scheme is due to begin shortly.

Why have other countries in the EU ceased water fluoridation?
At present, Ireland, the United Kingdom and Spain have water fluoridation programmes. The UK is preparing to expand its programme into Scotland in the near future.

Other countries ceased their programmes for a variety of reasons, none for health reasons.

Bottled water is favoured over tap water in most European countries making water fluoridation impracticable.

Countries such as France, Germany, Switzerland and Belgium use salt fluoridation instead.

What controls are there on the addition of fluoride to drinking water?
Fluoride added to Irish public piped water supplies is specified in the regulations under the Health (Fluoridation of Water Supplies) Act 1960.

The amount of fluoride added to the drinking water in Ireland is controlled by law to be in the range of 0.8 and 1.0 ppm fluoride.

The 1988 Irish Drinking Water Regulations specify the same upper limit for fluoride at 1.0 ppm. This level is 30% less than the maximum level of 1.5 ppm allowed under the new EU Drinking Water Directive

What percentage of the population have fluoridated water supplies?
Water fluoridation commenced in July 1964. Within six months, 25% coverage had been achieved and at the end of 1968, all major centres of population were receiving fluoridated water corresponding to about 50% of the population.

The percentage continues to grow as new regional water schemes replace small local schemes. Currently approximately 73% of the Irish population have fluoridated water supplies.

What materials are used to fluoridate water supplies?
Hydro-fluosilic Acid is used by all local authorities to fluoridate water supplies. Hydro-fluosilic Acid is produced as a primary product by the treatment of rock usually mined in North Africa. The product supplied for water fluoridation must meet a precise specification outlined in regulations made under the Health (Fluoridation of Water Supplies) Act in 1960.

Arsenic is sometimes mentioned as a dangerous impurity of Hydro-fluosilic Acid. A typical sample of the acid when dissolved in water at one part per million will result in arsenic in the water at the level of one part per 170 billion. This has no consequence for human health.

How is the fluoridation process monitored in this country?
Regulations made under the statute prescribe the limits for fluoride content of the water as being from 0.8 to 1.0 parts per million. They also provide for the determination of the fluoride content of the water by means of a daily colormetric and a distillation test every four weeks. The distillation analysis is carried by the Public Analyst on a sample of water taken by the Health Board's Environmental Health Officer. The result of the test is notified to the Health board, the engineer in charge of the waterworks and subsequently to the Department of Health and Children.

The most recent report of the EPA states: "there are no grounds for concern on the part of the consumer, because fluoride values are assessed in the context of the Irish Maximum Admissible Concentration which is two thirds of the concentration permitted elsewhere in the EU."


For further information contact:

Dental Health Foundation
26 Harcourt Street
Dublin 2

Phone: +353 1 478 0466
Fax: +353 1 478 0475
Email: info@dentalhealth.ie