Adam Cresswell, Health editor | December 01, 2007
BOTTLED water should be fluoridated to the same concentrations as public drinking water in order to reduce tooth decay, according to a revised policy by Australia’s top dental body.
The Australian Dental Association has reinforced its existing stance in favour of fluoridation, saying there is now “clear solid scientific evidence” that the practice is effective at protecting teeth.
“The claims of those opposing fluoridation are based on outdated information and selective studies that support their case,” the ADA said. “However, no convincing or credible scientific evidence exists that fluoride, when supplied at the optimum level (one part per million) in drinking water, causes any adverse health effects.”
ADA president and Melbourne dentist John Matthews says other changes in the revised policy relate to fluoride supplements, which the association no longer recommends in tablet form due to the risk of fluorosis, or mottling of the teeth.
However, Matthews says that although there has been a slight increase in the rate of dental decay among children, he does not believe the theory that this is caused by children drinking bottled water, which currently cannot be fluoridated by law.
Instead, he says it is more likely to be related to a deliberate reduction in the concentration of fluoride incorporated into children’s toothpastes. This concentration has been halved relative to adult toothpaste in order to be “extra safe” in reducing the risk of fluorosis, but the flip side may well be that dental caries rise slightly as a result.
“Fluoride should be added to bottled water at the normal level in reticulated (town) water, which varies from 0.6 parts per million to 1 part per million (ppm), depending on the humidity and water consumption,” he says. “In the bottom part of Australia the level (of added fluoride) is different to the top part.”
Fluoridation of drinking water remains contentious in some parts of Australia, particularly Queensland, where less than 5 per cent of drinking water supplies are fortified with the mineral — a stark difference to most other parts of Australia. Often the decision has been left to local councils, leading to emotive debates.
Although fluorides are naturally occurring compounds and are present in a wide variety of foods, usually at low concentrations, opponents of fluoridation focus on the fact that the element fluorine, from which they are derived, is toxic in its pure form.
Fluorides themselves can have harmful effects at high doses. Advocates of fluoridation say this is not a relevant criticism when the concentrations in drinking water are less than 1 part per million, and plenty of other compounds necessary for human health — including common table salt, comprising sodium and chlorine which are both essential for life — are also toxic in higher doses.
A circular about the new policy distributed by the ADA says recent Australian research has added to the weight of evidence in favour of the safety and efficacy of fluoride in drinking water. The circular says tooth decay is higher in Queensland than other states that have higher rates of water fluoridation. However, in Townsville — one of the few Queensland cities to be fluoridated, since 1964 — children have 45 per cent less tooth decay than their counterparts in Brisbane.
“Today, it is estimated that 31 per cent of Australian adults remain without access to fluoridated public water,” the ADA says. “Sadly, much of this is due to decisions made at local and state government level which have become politically motivated rather than based on scientific fact.”