Up to 700 dentists who provide free dental care to medical cardholders are to be balloted over the next two weeks on whether they should continue with the scheme.
The dentists, who are members of the Irish Dental Association (IDA), say the scheme is a bureaucratic mess and requires reviewing.
They also want their fees for providing care to medical cardholders renegotiated. They were last negotiated in early 2005.
Dr Séamus Quirke, chairman of the general dental practitioner group of the IDA, said that at present if a medical cardholder needed a denture, a dentist could not provide one without first seeking approval from the Health Service Executive (HSE).
This approval is meant to be given within 30 days but in "large tracts of the country it could take several months" to get it, he said.
The scheme under which dentists provide free care to medical cardholders on behalf of the State began in 1994. Dr Quirke said a review of the scheme was due to begin in September 2000 but it did not begin until September 2006.
As a result dentists had withdrawn from the scheme in significant numbers, Dr Quirke said, and were continuing to do so.
He added that the review of the scheme suddenly stalled in January 2007 as a result of legal advice obtained by the HSE. "It is now on the verge of collapse," he said.
The HSE is understood to have received legal advice to the effect that for it to negotiate fees with a union in future on behalf of its members would be in breach of competition legislation and could be regarded as price fixing.
Last night the HSE said it was only the fee-setting part of the review that had been put on hold pending clarification of legal issues.