As you may have already read in A New Cyst, I once had a cyst on my jawbone. Well without warning, I started to feel pain in the same way I had before and this time I didn't hesistate to go to the dentist, fearing that I had another cyst. As it turned out, my fears were unfounded. It turns out that when they had removed the cyst, the tooth above it had been damaged. This damage was enough to kill the tooth and it had been slowly rotting away in my mouth.
Simple to fix - a course of antibiotics and a root canal. The latter it turns out is a simple procedure a bit like a filling, except that where as a filling is simply capping a hole in the tooth, with a root canal, they remove the entire squishy contents of the tooth and fill it in. In effect, the tooth becomes nothing more than a lifeless hunk of enamel. Surprisingly, the treatment went smoothly and without pain. My dentist was surprised that I was surprised that it hadn't hurt - in fact I got the feeling she thought I was a typical whiney patient who didn't like dentists.
In part she was right, but that was because my previous dentist was a sadistic cruel bastard who seemingly enjoyed inflicting pain upon me. He would often perform treatments on my teeth without first checking if I was numb and would ignore my muffled screams of pain. As I was a child, I figured that this was meant to be the case, but now with this new dentist I could see I was wrong.
So anyway, tooth gets root canal'd. I get more antibiotics. Dentist gets money and the chance to see me lots to make sure it went well. And it did, although it never quite felt like it was OK...