Lots of "A&E with toothache!" posts here, so here's an alternative side to it: I had to go to A&E with toothache once - twice in one day, but bear with me.
I had a raging infection in my wisdom tooth. I had an appointment at the dental hospital a couple of days later for extraction - it was too complicated to be done at the dentist b/c the root was sitting on a nerve - and I'd seen the emergency dentist the night before who put some kind of paste on it, which did nothing, and gave me no pain relief. Meanwhile, I was in utter agony, because the root was exposed. Painkillers with codeine did nothing, the GP wouldn't help because it was a dental issue, and the dentist wouldn't help because I was already scheduled at Kings. Finally it got so bad that I left work and went to the nearest A&E to see if they could give me something, anything, for pain relief. They gave me Tramadol - it did nothing. Some hours later, still in agony, not just in the tooth but in my entire head up that side, I called the OOH dentist service, who called me back and said that since I'd already seen the emergency dentist, they couldn't do any more, and I was to go and buy Paracetamol. I explained that I'd already had Tramadol, which had made no difference. There then followed an argument about how Paracetamol was stronger than Tramadol (really?!) and I was to take that. By this time I was banging my head against the wall in agony. Literally the only thing I could do was go back to A&E in my local area (a different one) where thankfully in the Urgent Care Centre (it's attached, they're in the same place) they took me seriously and gave me the strong 30mg Codeine and a Diclofenac suppository and oh god the relief, I could have cried, I was so grateful to them.
It might have seemed frivolous but the pain was absolutely unbearable and there was literally no other option available to me.
When the tooth finally came out a couple of days later, the extraction took 45 minutes and the thing was so angry it was almost red. I took a photo of it for posterity :-D