MARK COLVIN: A new study builds on decades of research on the dental health benefits of fluoride by saying they extend into adulthood.

Researchers from the universities of Adelaide and North Carolina say they’ve shown that adding fluoride to water prevents tooth decay, not just in children but in people of all ages.

Some councillors in Queensland have been working to prevent the chemical being added to their water supplies.

Rebecca Brice reports.

REBECCA BRICE: The researchers say they’re filling a gap in the data.

KAYE ROBERTS-THOMSON: There is substantial evidence over many studies, over many years about the benefits of water fluoridation for children. We were undertaking a national survey of adults’ oral health and it seemed an opportunity to gather some information on whether water fluoridation had any effect on adult oral health.

REBECCA BRICE: Kaye Roberts-Thomson is the director of the Adelaide University’s Centre for Population Oral Health and one of the report’s authors.

KAYE ROBERTS-THOMSON: We interviewed over 14,000 Australians. We then did a dental examination on 5,500 examinations and we also collected data on where people had lived over many years since 1960.

Using their location of residence we could then match that with water fluoridation data, you know, pick the time at which water was fluoridated in a particular area. And using both the location and the water fluoridation status we could map out what percentage of each individual’s lifetime had been spent with the availability of water fluoridation.

REBECCA BRICE: So it’s not as though you’ve been following these people for sort of 10, 20, 30 years. It’s a retrospective look.

KAYE ROBERTS-THOMSON: It’s retrospective.

REBECCA BRICE: She and colleagues from the universities of Adelaide and North Carolina found that those who had fluoridated water had about 10 per cent fewer decays.

That increased to 30 per cent when teeth missing for reasons such as being knocked out during sport were excluded from the data.

KAYE ROBERTS-THOMSON: Given that you’ve got 32 teeth in your mouth, that’s what an adult would have, we can say that you are likely to have three fewer teeth with decay if you’ve had water fluoridation.

REBECCA BRICE: Dr Karin Alexander is the president of the Australian Dental Association.

KARIN ALEXANDER: It certainly vindicates our opinion that fluoride is a safe and very effective preventative measures, not just for children but even for adults. This is proper science, that’s been tested, it’s been refereed before being put out in a journal and it is the definitive statement.

REBECCA BRICE: The science has been questioned in Queensland where councils have been debating whether to continue water fluoridation.

Stuart Taylor is a councillor with the Fraser Coast Regional Council, it’s decided to phase out the practice.

STUART TAYLOR: We received a lot of correspondence in relation to it. All the submissions prior to our decision were against fluoride being placed in the water.

REBECCA BRICE: What were they saying to you?

STUART TAYLOR: Some were quite damning in the belief that the health impact on people taking industrial grade fluoride was quite severe. Others were very much against what they would class as being forced medication. Others were saying that it wasn’t cost effective.

I was an advocate for fluoride prior to researching this more thoroughly.

REBECCA BRICE: And what was it that changed your mind?

STUART TAYLOR: Well my main concern was, that sort of sparked my concern, was that much of the research was silent on the potential side effects and risks associated with long-term fluoride consumption. And it was these unanswered questions that I felt that I couldn’t take the risk to vote for fluoride to remain in our water.

REBECCA BRICE: He doesn’t think those questions are answered in the study.

Karin Alexander thinks differently.

KARIN ALEXANDER: People need to sit down and look at this research and not listen to scare mongerers who are making all sorts of wild accusations. Think about communities, think about the safety, think about how much they are going to enjoy having pain-free mouths and the ability to smile. ‘Cause once you’re put a filling in, you’re in fillings for life.

REBECCA BRICE: The study is published in the Journal of Dental Research.

MARK COLVIN: Rebecca Brice.