Health officials are being urged to consider reimbursing dentists here for the financial burden of purchasing better personal protective equipment.
Chairman of the British Dental Association's NI Dental Practice Committee Richard Graham was speaking as routine care resumed yesterday.
Dentists can now carry out aerosol-generating procedures (AGPs) such as fillings.
But there are restrictions, including up to one hour between some patients being seen so surgeries can be deep cleaned.
Dentists performing AGPs are expected to use full PPE.
This cost around 35-45 pence pre-pandemic - but could now stand at £20-30.
Mr Graham warned that as many as 90% of local dental practices may not be able to provide many procedures like fillings until level two PPE is secured.
"The number of patients we are seeing is down to a fifth of the level it was pre-Covid. You are talking about practices that saw up to 40 patients a day now being reduced to no more than eight," he said.
"Coupled with the high extra costs of level two PPE, which we have never needed before, this is making dentistry unsustainable."
He appealed for the Department of Health to cover the cost of buying higher grade PPE.
North Belfast dentist Alan Clarke said the industry is facing a crisis.
"If sustainable options of personal protective equipment are not made available, we will find that many dental practices will be forced to privatise simply to cover costs, not to turn a profit, or they will go bankrupt," Dr Clarke said.
The Department of Health said the delivery of £1m worth of level one PPE is due to commence this week. I added the minister has also announced that the financial support scheme, which has already provided £16 million in payments to local dentists, will continue for a further month.