Some dental patients in England are having to use emergency dental services after their dentists left the NHS.
Many dentists are unhappy with the new arrangements
One in 10 of England's 21,000 dentists left the NHS at the start of April after rejecting a new contract.
Local health bosses have struggled to replace them, leaving patients to ring help-lines.
Patients are then told of dentists accepting NHS patients - in some areas this is a minority - or diverted to services aimed at out-of-hours care.
Primary care trusts have taken on responsibility for commissioning dental services with the introduction of the new contract.
But with many dentists unhappy with the deal offered - they thought they would have been given more time to spend on preventative care - PCTs have been unable to open new practices to replace the ones that have gone private.
In Avon, where nearly a third of practices rejected the contract, patients are ringing help-lines and are told of practices that are accepting NHS patients.
But it is estimated four in five are not accepting new patients so instead they are being directed on to dental access centres, which provide emergency out-of-hours care.
John Boyles, consultant in dental public health to the five PCTs in the area, said: "There is a workforce problem. The dentists just are not there, there are plenty in dental school but they take time to train. It could take five years to resolve."
A similar system is in place in Hampshire and the Isle of Wight, which was the worst affected area in the country by the introduction of the new contract.
In Coventry, more than 8,000 patients were left without a dentist, leaving the local PCT to try to convince dentists that did sign the contract to take on extra patients.
But Lester Ellman, of the British Dental Association, said: "It is just not sustainable to keep asking dentists to take on more patients. They are going to start saying no.
"This contract has not improved access to services and I can't see it happening in the future."
Last week the government insisted PCTs were coping with the walkout - which affected nearly 1m patients - by recruiting graduates and using dentists from abroad.
The reforms were meant to introduce a simpler system of fees and reward dentists for carrying out more preventative work.
It also handed responsibility to PCTs to commission services where there was insufficient provision.
But the NHS Confederation, which represents health service managers, said PCTs had been handed a "tricky challenge".
Deputy director of policy Jo Webber said: "It is going to take a while to bed in."
A Department of Health spokeswoman said it was unfair to judge the reform as it was "early days".
"We are confident that in the future people will have much more access to services."