Millions of patients could be left with "no dental options" as thousands of high street dentists in England are "severing ties" with the NHS.
The British Dental Association (BDA) say that if the current trend continues "this is how NHS dentistry will die".
The BDA said that since March 2020, some 3,000 dentists were understood to have moved away from NHS work entirely.
Most dentists provide a mixture of NHS and private dental care, but new figures suggest the balance could shift in favour of more private provision.
Access to NHS dentists is one of the main worries for patients, with many unable to get appointments or being forced to wait months for care.
Minister for patient safety Maria Caulfield said the government had given the NHS £50 million to fund up to 350,000 extra dental appointments, but Feryal Clark, Labour's shadow health minister, hit out at "a decade of Tory mismanagement" of the service.
She warned that at the height of the UK's cost of living crisis, "going private is simply not an option for many".
A new poll of 2,200 high street dentists in England found 45% had reduced their NHS commitment since the start of the pandemic.
The figures also found 75% were "likely" to reduce, or further reduce, their NHS commitment in the next 12 months.
Almost two thirds (65%) said their practice had unfilled vacancies for dentists, while 87% said they have experienced symptoms of stress, burnout or other mental health problems in the last 12 months, according to the BDA poll.
The professional body is calling for "radical and urgent" action from the government to help struggling dentists.
It said the NHS dental contract, which was initiated in 2006, puts "targets ahead of patient need, effectively setting a limit on the numbers of NHS treatments a dentist can do in a year".
Shawn Charlwood, chairman of the British Dental Association's General Dental Practice Committee, said: "Overstretched and underfunded, thousands of dentists have already left the NHS, but many more have begun severing their ties.
"This is how NHS dentistry will die, a lingering decline that unchecked will leave millions of patients with no options.
"This government has ensured many dentists cannot see a future in this service. Without urgent reform and adequate funding there is little hope we can halt this exodus."
Members of the Commons Health and Social Care Committee are set to examine the issues in the sector at a meeting on Tuesday.
Minister for patient safety and primary care, Maria Caulfield, said negotiations were under way to improve contracts with the British Dental Association to ensure working in the NHS remained "attractive to dentists".
She added: "We have given the NHS £50 million to fund up to 350,000 extra dental appointments and we are growing the workforce so people can get the oral care they need.
"As we now learn to live with COVID, we have been working with the sector to safely increase activity and practices are now expected to deliver at least 95% of the activity they were delivering before the pandemic."