When you think of simple public health wins, a drop in child tooth decay is right up there. In Queensland, Australia, that’s exactly what’s happening. A new analysis shows oral health among schoolkids improved significantly after the state expanded water fluoridation. You can read the full findings in the ABC News report on the study.
The researchers measured decay in more than 7,700 children aged 5 to 14 between 2021 and 2024. In the 5-to-10 age group, 38.8% had at least one decayed baby tooth; back in 2010–12, that number was 49.5%. Meanwhile, the average number of decayed surfaces in that same age group dropped from 4.1 to 2.9, and that’s roughly a 24% fall. These are substantial reductions.
The gains were strongest in areas that only recently began fluoridating water. Lead researcher Loc Do, from the University of Queensland, said the improvements held up even when they adjusted for income levels and health habits. And it wasn’t just baby teeth: benefits persisted into the years when children had their adult teeth emerging.
Why this is such a big deal
Queensland mandated fluoridation in 2008, but in 2012 gave local councils the power to opt out. Over time, many did. Today, more than 70% of Queenslanders still get fluoridated water, mostly because major population centres kept it. But a majority of councils no longer add fluoride. In the past year, two councils voted to remove it, even as this new data shows the harm that can do.
Dentists and public health officials are pointing to this study as a warning. The Australian Dental Association said the methodology is strong and that the data provides powerful support for fluoridation policies. Queensland’s Chief Dentist also said, while he won’t comment on government policy, the evidence is now more useful than ever for local councils deciding whether to keep fluoride in their water.
This study hasn’t been peer-reviewed yet, and further cost-benefit and long-term research is underway. But right now, it stands as one of the largest before-after assessments of fluoridation’s impact globally. In areas where fluoride was added, decay fell harder and faster.
Public health measures often live or die in the margins. Here, fluoride dissolved decades of debate into something measurable: fewer cavities and easier school mornings for kids who aren’t doubling up on dentist visits.
This isn’t magic. It doesn’t replace brushing, good diet or access to dental care. But fluoride in water is a low-effort, broad-reach tool that helps everyone, especially families who don’t have the means, time, or access to dental services.
So when debates flare about whether “government should add stuff to water,” these results make it harder to dismiss the upside. Queensland’s numbers tell one simple story: putting fluoride in tap water helps kids keep their teeth. And that’s something worth listening to.