To the dentist today for a root canal filling. These aren't as scary as they sound, or at least, not the way my dentist does the job. Drilling isn't as awful as it used to be when they used actual rotating steel bits; now it's all done with high speed jets of water. Well, nearly all - he does a bit of filing sometimes.
Anyway, the tooth in question had three roots, of which two were filled with dentine (tooth-stuff). He did the main one that had got infected, and then he did the other two. I can't imagine how fiddly this must be, but we used to use dentistry tools in the data recovery business, because the working parts of hard drives had become very small. At least we didn't need to worry about anaesthetic!
The tooth feels good and solid now.