I've had, I think, 3 root canals. I'm a major chicken when it comes to dentists. For my first one, I had nitrous.
Just regular novocaine for the second 2, and i was fine. My husband only had one, about 15 years ago, and all of a sudden one day last month it started hurting him. Turns out he had a major abscess. They drilled down through the crown and the original root canal, drained it some and filled it, gave him some Vicodin and anti-biotics and sent him on his way. That happened the day we left for Disney World. A week and a half later it still hurt and looked like he had a golf ball in his mouth. More antibiotics and lots more drainage, and more painkillers. He seems to be okay now, but he has to go back tomorrow to make sure. The weird thing is the exact same thing just happened to TWO of my neighbors! Old root canals, abscessed, terrible pain, etc. Weird.
But I'm sure you'll be fine!
Good luck!!!!!
Carol