A new study shows that fluoridated water is safe and does not affect children's development. 

A longitudinal study by experts at the University of Queensland assessed 2,682 children between the ages of five and 10 from Australia's National Child Oral Health study, following up with them seven to eight years later.

It looked at the difference between the brain development and function of children who had been exposed to fluoridated water in early childhood with those who had not.

It finds that drinking tap water with fluoride does not hinder a child's emotional or behavioural development, and there was no difference detected between children who lived in the different postcodes.

No difference was found in the development of their higher functions either.

About 90 per cent of Australia’s water has fluoride added to it, but only around 70 per cent of Queensland councils use fluoride.

Fluoride is commonly added to water supplies because it helps to rebuild and strengthen the tooth's surface, or enamel. Water fluoridation prevents tooth decay by providing frequent and consistent contact with low levels of fluoride. 

Some regional Queensland areas and Aboriginal and Torres Strait Islander communities are among those not covered by a fluoridation program.

Australia has long been home to an anti-fluoride movement, which makes claims about fluoride causing cancer, allergies, arthritis, bone fractures and affecting child development. 

Study lead Loc Do, from UQ's School of Dentistry, says the latest findings show some of these claims to be untrue. 

“A small but vocal group of people sometimes claims that water fluoridation can have adverse neurodevelopment effects, especially in young children,” Professor Do said.

“This concern can impact community and public health support for the practice, but our research provides reassurance that it is safe and supports its expansion into more communities.”