Dentists have warned people will lose teeth because of high demand for personal protective equipment in hospitals.
Already some patients have been fending for themselves when treatment is unavailable because of coronavirus.
One woman said she replaced a filling with Blu Tack as a result of limited services.
Llandovery dentist Tom Bysouth said dentists faced "horribly difficult ethical dilemmas".
"It may boil down to the question of is it better to save a tooth, or is it better to save a life," Mr Bysouth, who sits on the Welsh General Dental Practice Committee, said.
Mr Bysouth said emergency dental hubs - set up after practices stopped offering face-to-face appointments- have "a very limited stock" of safety gear.
Phone consultations, pain relief and antibiotics prescriptions are available but treatment is limited only to the most urgent cases.
Mr Bysouth said the use of suction, sprays and drills in the mouth created the "ideal environment for the spread of coronavirus".
Cardiff oral surgeon, Lowri Myrddin, said in a letter to First Minister Mark Drakeford that protective supplies were running out with potentially "catastrophic" effects on healthcare staff.
The Welsh Government said providing the right equipment to dentists was a priority, but "all routine dental care, treatments, and check-ups have been cancelled for the time being".
It said safety gear requirements were continually reviewed so it could go "where it is needed most".
'I used Blu Tack to fill my tooth'
Some patients have taken a DIY approach.
Marilyn Jones, of Aberystwyth, said she lost a filling the day after dental practices closed. So, instead, she used Blu Tack to fill the gap.
Mrs Jones, 66, said: "You have to improvise, necessity is the mother of invention.
"I thought, 'What can I use?' The only thing I had was Blu Tack.
"My husband offered me his chewing gum but I decided on the Blu Tack.
"I wasn't very happy with a little black stump."
The mother-of-two and grandmother-of-four has since fixed it with a dental pack from Boots - but she still needs proper treatment.
What help is there for dentists?
Mr Bysouth said the Welsh Government had offered a package of help to NHS dentists, but private practitioners would have to depend on the UK government support scheme.
That is limited to people making under £50k a year.
"We don't know how long it's going to last," he said.
"There are some practices that might be able to survive on three months help, there are some practices that might be able to survive on six months of help, there are some practices that might be able to survive on a year of help, because every practice is different."
He said he feared a backlog of work was being created.
"We are in fact saving up a lot of additional treatment for when things get back to normal, and this is going to put a big demand on an already stretched dental service," he added.