How fluoride in water helps prevent tooth decay

Fluoridated water protects against the tooth decay from acid produced by bacteria in the mouth. T. Faltings

The most effective way to prevent tooth decay is delivered to most Australian homes every day through their water pipes. It is, of course, fluoride distributed via the water supply.

Dental decay occurs when acid destroys or demineralises the outer surface of the tooth – the enamel. Bacteria in the mouth from food and drinks containing sugar produces acid and fluoride repairs demineralisation before it becomes permanent. It does this by encouraging remineralisation or repair of the enamel surface. Fluoride also helps strengthen the mineral structure of developing teeth.

Fluoride is a naturally occurring compound found in plants and rocks and, in very low levels, in almost all fresh water. Sometimes, fluoride is found naturally in the water supplies of Australian communities at exactly the level recommended to reduce dental decay, but this is rare and happens by chance.

Community water fluoridation is the adjustment of fluoride in drinking water to a level that helps protect teeth against decay. Drinking water in many parts of Australia has been fluoridated since the early 1960s.

Fluoride helps strengthen the mineral structure of developing teeth. Jens Gyldenkærne Clausen

Although widely accepted and applauded as a crucial public health policy, fluoridation has attracted some vocal critics. Fluoridation opponents over the years have claimed that putting fluoride in water causes health problems, is too expensive and is a form of mass medication. Some go as far as to suggest that fluoridation is a communist plot and affects children’s IQ.

Despite these claims, fluoridation is supported by many national and international organisations including the World Health Organization, World Health Assembly, World Dental Federation, Australia’s National Health and Medical Research Council (NHMRC), Australian Dental Association and the Public Health Association of Australia.

In 2006, the WHO and the International Dental Federation and the International Association for Dental Research, released a statement endorsing community water fluoridation.

And the Centers for Disease Control and Prevention (CDC) in the United States includes water fluoridation in its list of the top ten health initiatives of the twentieth century, alongside immunisation, compulsory seat belt wearing and smoking bans.

In November 2007, the NHMRC completed a review of the latest scientific evidence in relation to fluoride and health. Based on this review, the NHMRC recommended community water fluoridation programs as the most effective and socially equitable community measure for protecting the population from tooth decay. The scientific and medical support for the benefits of fluoridation certainly outweighs the claims of the vocal minority against it.

Luc De Leeuw

The recommended level varies around Australia and depends on the annual average maximum daytime temperature. In Victoria, for instance, the maximum level of fluoride added to drinking water is one milligram per litre or one part per million as recommended by the World Health Organization.

In hotter climates where people drink more, the recommended level can drop to around 0.7 parts per million. As a comparison, the amount of fluoride in children’s toothpaste is 400 to 500 parts per million. In regular toothpaste, it’s 1,000 parts per million.

We’ve known about the role of fluoride in reducing dental decay since the early part of the twentieth century and some countries, such as the United States, have been adding it to water and toothpastes since the 1950s.

Canberra was the first Australian capital city to be fluoridated – back in 1964. Melbourne has had community water fluoridation since 1977. And other parts of Australia have had fluoridated drinking water for more than 50 years.

Joost Nelissen

Some communities in regional and rural Australia, previously without optimal water fluoridation, have recently started to receive fluoride through their drinking water as part of a program to prevent tooth decay and improve oral health. Australia has now achieved overall population coverage of 90%.

But tooth decay remains significant problem. In Victoria, for instance, more than 4,400 children under 10, including 197 two-year-olds and 828 four-year-olds, required general anaesthetic in hospital for the treatment of dental decay during 2009-10. Indeed, 95% of all preventable dental admissions to hospital for children up to nine years old in Victoria are due to dental decay.

Children under ten in non-optimally fluoridated areas are twice as likely to require a general anaesthetic for treatment of dental decay as children in optimally fluoridated areas.

Community water fluoridation remains a vital public health activity and has a key role to play in preventing dental decay and improving oral health for all Australians. The provision of drinking water through our pipes was never more important.