I have never had nitrous oxide. Cyber swears by it.
Ordinarily, I don't need it. But my doc knew I was going to be there for a while and needed to make sure I stayed as still as possible while they were working, ergo the nitrous. I brought my MP3 player, put on the headphones, and all but dozed through it.
Jaw's still sore from all the prodding around, but it's manageable. On the whole, a very easy time of it in the chair.
.... until I can negotiate a good deal for with Vivid Video.