Fewer than half of children saw a dentist in the past year in England, with opposition MPs warning parts of the country have become “dental deserts”.
Data commissioned by the Liberal Democrats found there are as many as 3,000 people per NHS dentist in some English areas.
Lib Dem leader Sir Ed Davey is expected to caution on Wednesday that the dental crisis is leading desperate people to resort to performing so-called DIY dentistry.
His party is calling for an NHS dental healthcare plan to ensure every person can access affordable dental care.
Sir Ed, who is ramping up campaigning ahead of the local elections next month, wants reforms to the NHS dental contract and is pressing for additional resources for mobile dental units to visit schools, community centres and care homes.
He is also demanding the removal of VAT on children’s toothbrushes and toothpaste.
“The staggering rise in dental deserts has left far too many people struggling to get an NHS dental appointment,” Sir Ed said.
“It is heart-breaking that people are being left waiting in pain for months or even years for the dental care they need.
“Many are being forced to shell out thousands of pounds on private dental care, while some are even turning in desperation to DIY dentistry.
“This Conservative Government has been asleep at the wheel for years and allowed this dental crisis to get worse and worse.
“We need to see action now to make sure everyone can see a dentist on the NHS when they need to.
The former cabinet minister, speaking to BBC Radio 4’s Today programme on Wednesday, said the NHS dentistry contract effectively asks dentists to supply services “for free”.
He said a “radical change” to its terms could help boost NHS dentist numbers and the availability of appointments.
He added: “We can reform the contract and if we get the right incentives, encourage these dentists to come into NHS dentistry, we can help people who are in acute pain.
“I think the Government has got NHS dentistry wrong and there are people out there, perhaps more cynical than me, who say the Tories frankly just want to kill off what remains of NHS dentistry.”
Commons Library research commissioned by the Lib Dems showed that fewer than one in two (44%) children saw an NHS dentist in the last year, while just one third of adults saw an NHS dentist in the past two years.
Out of 104 local areas in England, 65 have seen the number of people per dentist rise since 2019, the figures indicate.
North Lincolnshire, as of 2021/22, has just one NHS dentist for every 3,199 people – a higher ratio than anywhere else in the country.
Nationally there are an average of 2,330 people per NHS dentist in England.
Bolton has seen the sharpest rise in people per NHS dentist, with the number rising by 35% since 2019 to 2,044.
Other areas with the sharpest increases in population per dentist include Ipswich and East Suffolk (26%), West Suffolk (19%) and Barnsley (13%).
In the Savanta ComRes survey of 2,234 UK adults carried out in August, 21% said they attempted to carry out dental work on themselves or asked somebody else who was not a dentist to assist them.
Another 26% delayed seeing a dentist despite suffering pain, while more than a quarter paid for private treatment.
The British Dental Association (BDA) said its own data indicated that hundreds of dentists were undertaking the equivalent of a single NHS check-up a year.
Eddie Crouch, the association’s chairman, said: “Dental deserts are on the rise, but the true scale of the exodus from the NHS is going untracked in official data.
“The Prime Minister keeps boasting of 500 ‘new’ dentists in the NHS. The reality is we have 500 doing a single check-up a year.
“We need a reality check from government, together with honesty, ambition and investment.”
The Department of Health and Social Care said ministers were preparing to announce further measures to “improve” access to NHS dental surgeries.
A spokesman said: “We are working to improve access to NHS dental care by investing more than £3 billion a year.
“We reformed the NHS dental contract to encourage more dentists to provide NHS treatments and allow dental therapists and hygienists to offer extra services, and increased the amount practices receive for high-need patients.
“There were over 500 more dentists delivering NHS care in 2022 than in 2021, but we know there is more to do and we will be announcing further measures to improve access across the country soon.”