Chinese supply problems have prompted the British Dental Association (BDA) to predict that some larger clinics in the UK will run out of masks by the middle of next week and will not be able to treat patients safely under current rules.
A spokesman said more than 50% of face masks used by dentists and other health professionals in the UK are made in China but export of masks from Chinese manufacturers have "essentially ceased”.
UK suppliers are now restricting the amount that can be ordered, with some suppliers out of stock and others tripling their prices, the spokesman said.
Some dentists and health professionals have also been panic-buying as they anticipate a shortage, while the BDA said it had been "bombarded" with calls.
BDA chairman Mick Armstrong said: "In recent weeks dentists have been hit by panic-buying, clumsy rationing and naked profiteering.
"Sadly a 'one size fits all' approach from suppliers is leaving many larger practices with few options.
"Our abiding interest is the safety of our patients, who face imminent disruption to their care.
"Unless we see a rapid increase in supply, dentists without face masks will have little choice but to down drills.”
The BDA warned that UK suppliers have issued blanket restrictions, which say dental practices can order no more than two boxes of masks per day – 100 masks in total.
The masks are used by dentists and dental nurses, and are also used when sterilising equipment.
The BDA estimates that a single surgery in a typical NHS practice, seeing about 28 patients per day, will be getting through five boxes of masks a week. They account for about a fifth of all practices in the UK.
But "two-chair" NHS practices are likely to use up their allocation completely, and larger practices will not have enough to continue opening.
Under current guidance, all dental professionals operating in England are told to wear personal protective equipment, including disposable face masks, clinical gloves, disposable aprons and eye protection.
The BDA said similar issues are being seen in New Zealand, Australia and Canada.