About 20 odd years ago my brother had a massive abcess, he had visited his dentist a few days earlier because his lower jaw was aching, the dentist couldn't be arsed to look (he was getting ready to close for Christmas) and just said had a bit of cold in his jaw.
Two days later on Christmas morning, my bro's jaw had swollen to twice the size and he was in hell of a lot of pain. My Ma and Da took him to the Dental hospital in Newcastle, the doctor who saw him said just as well they came as the abcess was near to bursting and could have been dangerous for my brother as he could have swallowed the poison.
I remember my dad being really furious. Couple of days later, he sat in his car outside the dentist's surgery waiting for the poor bloke to turn up, not too sure what my Dad intended doing I think he was going to punch the bloke's lights out! Luckily for him the dentist had taken extended leave and wasnt opening for another few days.