Did it come across as sarcastic? I certainly didn't intend that, of course they have more important things to worry about. They'd usually come in to do a day's work and now suddenly everything is closed and they've got to write this weird open-ended letter.

It's an NHS dentist, so unless we have millions of deaths I expect the practice will continue to exist and receive funding as before. Such practices are funded partially on the basis of the number of patients who are notionally "theirs" to look after and that hasn't changed even if providing non-emergency services is not a priority now.