According to a recent BBC article:
'What happens if you need to see a dentist?
In the first instance, patients are advised to call their local practice.
If symptoms are serious, local dentists can prescribe medication over the phone (such as painkillers and antibiotics). In such cases, dentists can contact local pharmacies, which can then prepare medication for patients to pick up.
However, a number of patients cannot be seen for emergency appointments because most practices are not allowed to see patients face-to-face.
In those circumstances - or if a patient is not registered with a dentist - then the advice is to use the 111 online service.'
So it would seem that 111 are they way to go if you can't get help locally. I understand that hubs are being set up.