Thousands of patients are being given an ultimatum - go private or start looking for another NHS dentist.

In the latest blow to dentistry a long-established practice in Bishop Auckland is going private.

More than 4,000 patients who are registered with the Auckland Dental Practice in Cockton Hill Road, Bishop Auckland are being notified about the change by letter.

The practice is moving adult dentistry into the private sector while continuing to treat under 18s on the NHS.

Patients are being asked to come in and discuss whether they are willing to sign up for a dental insurance scheme which would work out at around £198 a year to provide basic cover.

But if they want to stay as NHS patients they will have to look elsewhere.

That might not be easy as there is little spare capacity among NHS dentists in County Durham.

Health bosses will try to find alternatives but have warned that patients may have to travel.

Phil Greenwell, a partner at the Auckland Dental Practice, said: "We have made a decision, mainly to try to maintain more quality of care. At the moment, because of the way the NHS works, we feel that we cannot give our patients the time we need to take."

Faced with the prospect of having to take on even more patients under new Government proposals, the practice had decided to give patients the chance to opt for better quality care in a less hectic environment.

Mr Greenwell firmly denied that the motive was to increase income.

David Landes, director of public health with Durham Dales Primary Care Trust, said: "Of course, we are disappointed. Obviously, we believe it is a regrettable decision. It came as a surprise to us."

Mr Landes said the PCT would try to find local practices which are still taking new NHS patients.

Under new funding arrangements the withdrawal of a dentist from the NHS would mean a substantial sum would now be returned to the PC to appoint salaried NHS dentists in the area.

Meanwhile, a company which specialises in arranging trips to Hungary to have heavily discounted dental work has said it is targeting the North-East.

Chris Hall, director of Hungarian Dental Travel, claims that by using cheap flights from Newcastle airport private patients can save up to 80 per cent on dental bills.