Disadvantaged regions of Queensland are more at risk of dental decay because of a lack of fluoride in their water supply, a study has found.
It has prompted calls for the Queensland government to reclaim water fluoridation responsibility.
The study found 61 out of Queensland's 77 local government areas do not have fluoridated water, affecting more than one million people.
The proportion of the population with access to fluoridated water was lower in Queensland than in all other Australian states and territories, researchers from the University of Queensland found.
The state government handed over responsibility for fluoride in the water supply to local councils in 2012.
Researchers found Queenslanders living in lower socio-economic status areas now have less access to fluoridated water, putting them at greater risk of dental decay.
Access to a fluoridated water supply is concentrated in higher socio-economic areas in southeast Queensland, the study said.
The decision to hand responsibility to local councils meant more disadvantaged areas were less likely to have access to fluoridated water and dental disease was set to rise, the researchers claimed.
"In this study, we investigated area-level access to fluoridated drinking water in Queensland and its relationship with local socio-economic resources," said study co-author Christopher Sexton of the University of Queensland.
"Access to fluoridated water can reduce inequalities in oral health by benefiting people at all socio-economic levels.
"But socio-economically advantaged regions often have access to fluoridated water sooner and for longer."
Water fluoridation reduced the prevalence of dental decay by 25 to 40 per cent, he said.
Mr Sexton said people in disadvantaged areas would benefit most from drinking fluoridated water because they were at greater risk of dental disease and less likely to have access to other forms of oral health care.
The responsibility for water fluoridation must be handed back to the government, he said.
"The Queensland government should revise its water fluoridation policy and support local councils, especially in regional areas, to implement water fluoridation," the study said.
"The alternative is to accept poorer access to fluoridated water in poorer areas of Queensland, where the burden of oral disease is already high."
Health Minister Shannon Fentiman on Monday said the government would love to see more Queenslanders access fluoridated water.
She said the government would work with regional councils to help them with water infrastructure.
"I'm very happy to work with the water infrastructure minister and local councils to see what we can do," Ms Fentiman said.
Data regarding fluoridated water by postcode area was obtained from Queensland Health for the study, and it was confirmed by directly contacting councils that regulated water services prior to March 2022.
The study can be found in the Medical Journal of Australia.
