More than 25 dental practices in North Yorkshire have refused to sign new NHS contracts, according to figures set to go before county councillors.
Another six have also decided to opt out of providing NHS treatment since the new contracts began on 1 April.
The figures are being presented to the Scrutiny of Health Committee to assess the level of dental care provided throughout the county.
Only 110 practices agreed to the new deal to continue offering NHS services.
Children only
Under the latest contracts, Primary Care Trusts are responsible for commissioning dental services and the way dentists are paid has changed.
Instead of being paid for every NHS treatment they carry out, dentists are being given a guaranteed income based on their historical income for three years taking into account the service they provided to the local community.
The departure of at least 27 practices from the NHS in North Yorkshire has left thousands of people without access to an NHS dentist.
Of the 110 practices that signed the new contracts, 27 did so in dispute and have been referred to the NHS Litigation Authority for arbitration.
Several other practices have reduced their NHS commitment to treat children only.