Rebecca Curtayne, from patient watchdog Healthwatch England, said: “These figures reflect what people across the country tell us – many cannot get an NHS dental appointment and others find their dentist has stopped providing NHS care altogether and now only offers private treatment.
“The impact falls heaviest on those who are already vulnerable, especially people who struggle financially, who are left with nowhere to turn under a dental contract that is simply not fit for purpose.”
The government said it had increased the amount dentists get for NHS work and provided £20,000 golden hellos to get dentists to work in areas with the poorest access.
This is increasing the number of treatments being carried out, the government said.
It is also looking to fundamentally reform the dentistry contract by the end of the parliament to boost access further.
Health and social care minister Stephen Kinnock said the government was “making progress”.
But he added: “We know there is more to do to get to the root of the problem.”
An NHS England spokeswoman said the clawback data was effectively “a year behind reality” and money being returned was reinvested into dentistry.
“We are working closely with government to introduce further reforms in the coming months.”