Most Australian cities have been adding fluoride to their water since the 1960s and 70s, with significant evidence by the National Health and Medical Research Council and the World Health Organisation showing the natural chemical helps reduce tooth decay.
But there are eight towns left in New South Wales that don't have fluoridated water. Oberon, in the state's central west, has just voted to change that.
The council voted five to three to introduce fluoride in their water at a meeting this week, but the decision has been met with some pretty fierce backlash.
Some residents are calling water fluoridation "mass medication", while others are even considering legal action against the council, believing they've ignored the community's wishes.
Oberon resident Tina Slattery says she's relieved by the council's decision.
"It's fabulous, given what we know about teeth I couldn't be more delighted," she told the local ABC.
Tracey Watson believes the council have gone against the wishes of Oberon.
"I'm mortified," she said.
There's a lot of fear surrounding fluoride, with some believing it causes kidney and thyroid problems and even cancer.
What does fluoride do?
Fluoride is a chemical ion of the element fluorine and is a part of the earth's crust.
If that made no sense to you as well, it's basically a naturally occurring component of mineral salts found in soil, rocks, plants, animals and natural water sources.
According to the National Health and Medical Research Council (NHMRC), fluoride reduces demineralisation of teeth and enhances remineralisation.
It's a repair kit for teeth," Matt Hopcraft, a clinical Associate Professor at the Melbourne Dental School at Melbourne University, told Hack.
"Evidence shows us that fluoride works really well. For kids, tooth decay is reduced by around 24 — 40 per cent, and for adults it's about 25 per cent."
Matt said the majority of the Australian population has access to fluoridated water, but that hasn't stopped the mistrust by some that the chemical causes serious health problems. That's despite multiple reports and support from the World Health Organisation.
"There's no credible evidence anywhere in the world and certainly not here in Australia that drinking water supply with 1 part per million fluoride is linked to cancer, skeletal problems, kidney problems," Matt said.
Too many lollies or not enough fluoride?
Hack reporter Jo Lauder has first-hand experience of what it's like to grow up without fluoridated water. Jo grew up in Tumbarumba, a small country town in the NSW Snowy Mountains, and when she was 17 she visited the dentist.
The visit went something like this:
Dentist: Do you brush your teeth?
Jo: Yes.
Dentist: Do you know how to use toothpaste?
Jo:...yes
Dentist: How many times a day do you eat lollies and drink soft drink?
At that point Jo mentioned she grew up in a town without fluoride in the water, which made the dentist go, "Ohhhh, right". Jo still has to get nine fillings though, and has had around 11 more since then.
Tumbarumba has since introduced fluoride in the water.
"The healthiest teeth in Australia come from fluoridated towns"
While Oberon Council's vote to add fluoride to the town's water supply will now be referred to NSW Health, on the other side of the state, Byron Bay Council is refusing to introduce fluoride.
Mayor of Byron Shire Council, Simon Richardson, said his council are "standing alongside the 150 countries in the world who don't do it".
"There's only about 25 countries in the world who do [add fluoride to water]," Cr. Richardson told Hack.
He said the council wants its residents to have healthy teeth, but are looking at other ways to include fluoride.
"In Japan, they target kids by putting fluoride mouth-rinsing programs in schools, rather than a mass dosage for the whole population," he said.
"People have a choice to add it to their toothpaste, their milk or salt, the question is should everyone have it in their water when there are more effective ways to do it."
Dentist and fluoride expert from the Australian Dentist Association, Dr Michael Foley, said while there are many ways to introduce fluoride in oral health, water fluoridation is the best.
Water fluoridation is considered by the WHO and major health organisations in Australia to be the gold standard," he told Hack.
He argues against an opt-in scenario for water fluoridation because "in a small community, you'll never have everyone agreeing on it".
"Governments are paid to make decisions...and water fluoridation is simply a very sensible public health measure," he said.
Dr Foley said the decision to allow local councils to opt-in was debated in the 1968 Tasmanian royal commission into water fluoridation.
The first community in Australia to have water fluoridation was Beaconsfield, Tasmania in 1953.
"The commission said the decision should not rest with local councils, because they simply do not have the expertise on public health," Dr Foley said.
But Cr. Richardson argued that's not the law in NSW.
"At the moment, local governments have the power to make decisions for the community and part of my role is to balance community expectations and different degrees of expert opinions, and do what's best for my community," he said.
During his time as a former army dentist, Matt Hopcraft said it was easy to tell where new recruits were from based on their teeth.
"The buses would come in from Sydney and Melbourne, where the water was fluoridated, and these 17, 18-year-old people would have very little tooth decay," Matt said.
"Then the bus would come in from Queensland, where the majority of the state wasn't fluoridated at that stage, and you could see tooth decay everywhere."
For Dr Foley, the case is clear.
"The healthiest teeth in Australia come from fluoridated towns."