The dental divide between rich and poor Australians has continued to grow, with revelations millions of Australians avoid food because of problems with their teeth.

Key points: A third of Australians eligible for public dentistry avoid food due to dental problems

A third of Australians eligible for public dentistry avoid food due to dental problems A quarter of these Australians have fewer than 21 of 32 teeth in an adult mouth

A quarter of these Australians have fewer than 21 of 32 teeth in an adult mouth 180,000 Australians rely on a national partnership agreement for dental care

A quarter of people with access to public dental care do not have the minimum amount of teeth needed for their mouths to function efficiently.

The figures from the Australian Dental Association (ADA) also revealed tooth decay and gum disease was on the rise.

Sunshine Coast resident Callie Westbrook was left with just 12 adult teeth at 37.

She spent six years on and off the Queensland public dental waiting list, which compounded problems like decay.

"Little issues developed into bigger issues that became even bigger issues that ended up being a whole mouth problem, because there was such a long time between visits and the wait times were just extraordinary," Ms Westbrook said.

She remembers a six-month period in particular when she was knocked back for emergency dental care despite having an abscess — a painful collection of pus often caused by bacterial infection.

"It was beyond excruciating. It is the only thing you can think about," she said.

"I remember more times than you can shake a stick at, at two o'clock in the morning on the phone to my mother sobbing my eyes out going 'Mum I can't do this, Mum I can't do this'."

Public patients facing worse outcome than private

The latest snapshot of Australia's oral health shows people on public dental waiting lists typically have far worse outcomes than those who can afford private care.

About 33 per cent of the millions of Australians eligible for public dentistry avoid food because of problems with their teeth, compared to about 20 per cent of other Australians.

The 24 per cent of people who can access public dental care and do not have the number of teeth required for the mouth to function properly compares to just 5 per cent of other Australians.

The number of adults with untreated tooth decay has also increased since 2018, from 25.5 per cent to 32.1 per cent.

ADA deputy chief executive Eithne Irving said it was a reminder that the oral health of Australian adults was tracking in the wrong direction.

"There's been calls for the Government to put the oral health and the mouth back in the body, because a lot of people are missing out," she said.

"Having adequate teeth is absolutely essential to being part of society."

Some Australians waiting more than two years for care

As the number of wealthy Australians and social media influencers forking out millions each year — or posting endorsements — in exchange for the perfect selfie smile grows, about 8 million others need public dental care just for the basics.

The ABC has obtained waiting times from each jurisdiction, which showed pressure across most of the states and territories.

The median wait time for public dental care in Tasmania was about 21 months, while the latest figures from the ACT, Western Australia and South Australia revealed people in those jurisdictions were all waiting about a year on average.

In New South Wales, there was an average wait time of six months.

In Victoria, the average wait time was 18 months while in Queensland, the median wait time was 19 months.

The Northern Territory Health Department did not provide the ABC with the latest wait times, instead referring it to the latest figures on record from 2017-18, which show a median wait time of 26 months for public dental care.

Ms Irving said the waiting times could not be directly compared between the states and that posed a big problem.

"We don't have a minimum data set about waiting lists," she said.

"Each state and territory reports their waiting times in a different way. This needs to be addressed so we can get a more accurate picture across the country of the waiting times."

Question mark over federal government funding

The states and territories run public dental clinics but receive federal funding for adults under a national partnership agreement (NPA).

The current $350 million agreement began in January 2017 and is due to expire in June.

In a statement, a spokesman for Health Minister Greg Hunt said decisions about the agreement were a matter for the Government and would be considered in this year's budget.

"States are responsible for the delivery of public dental services and the management of waiting times," he said.

"The Commonwealth has provided assistance to states and territories over a series of NPAs. This funding is designed to provide additional services on top of those provided by states and territories. Under these arrangements, states continue to be responsible for the delivery of public dental services."

Opposition spokesman for health Chris Bowen said that was unacceptable.

"The Federal Government must recommit to the national partnership agreement urgently, Australians need to know they can get their teeth fixed when necessary," he said.

"Too many Australians avoid dental care already, we need to be doing more, not less."

Callie Westbrook's dental nightmare came to an end when a private dentist offered her free care. ( ABC News: Owen Jacques )

Ms Irving said if the NPA was not renewed, tens of thousands of Australians would miss out on vital treatment.

"The ADA believes if the national partnership agreement is not renewed, around 180,000 patients each year will miss out on the necessary dental treatment, that will equate to around 720 patients every day who don't get the dental care they need," she said.

Tony McBride from the Victorian Oral Health Alliance said the Government was putting services at risk.

"It's only three and a bit months until the agreement finishes. And that will put a lot of strain on services that are funded by that slice of money," he said.

"Even people who don't rely on public care are shocked that people should have to wait 20 months for basic dental care. Australians see that as really unfair, inequitable, unjust, a blind spot in government thinking.

Callie Westbrook's dental nightmare came to a close last year, when a private dentist heard about her story and offered her free care.

While it provided her with relief and two dental plates, giving her a picture-perfect smile, she ultimately lost 20 teeth.

She believes dental care should be covered under Medicare.

"So you can get your teeth sorted out and looked after before they get to the stage when you're 37 years old and half your mouth is full of plastic.

"When's it going to stop. When's it going to change?"