At the moment I'm currently part way through a root canal on a lower back molar. I have what is called a hypoplastic tooth, which is where the tooth forms without any enamel and crumbles. The tooth was filled and was fine for about 5 years until the filling started to leak. For 6 months without me knowing an infection was brewing under my tooth and by this time it started hurting (pain I have never ever experienced before it was agony).
So dentists tried to re-fill the tooth but the previous filling was too deep and it was too infected so they ordered a root canal. I did 2 courses of antibiotics at this point - amoxicillin I believe.
So first root canal appointment (they hoped it could be completed in one sitting but more on that later) they tried to numb me up but due to the infection it took about 3 shots. That wasn't too bad - slightly painful but nothing terrible. Then they drilled a hole in the centre of the tooth down to the pulp/nerve. This didn't hurt. Then it was time to actually drill out the nerve (back teeth have 3/4 nerves, front 1 nerve) - I believe the dentists either use hand files to do this or an electric file. Mine was done with an electric. Anyways as soon as they touched the nerve I screamed because it hurt so bad, so they had to inject more anaesthetic into the nerve about 6 times, that hurt aswell but apparently doesn't usually. When they eventually filed into the nerve loads of pus and stuff came out, it was vile. Turned out the antibiotics hadn't worked and by this point the dentist decided they couldn't do anymore work on the tooth, so packed it with other antibiotics and cotton wool to draw out the rest of the infection. Took about 60 minutes.
I was told after this it shouldn't hurt but it did due to the infection still being present. Had to go back to the dentist and complete another course of antibiotics - metranidizole and I'm on super strength painkillers around the clock - dihydrocodeine. Because otherwise I wouldn't be able to eat due to pain. I'm also on sleeping pills because it hurts so much at night lying down. I also have some residual numbness of my tongue and right inner gum due to the nerve being bruised and compressed by the spreading infection. It's really really nasty.
I have to return May 22nd for the next appointment to see if there is still infection in the tooth, if so it will have to be cleaned again and then left and if the infection is gone the tooth will be cleaned out and sealed and filled. This will be another 60 minutes.
I guess to be honest I've just had a really bad experience because my tooth is so badly infected. I guess if you're tooth isn't infected or the infection is cleared beforehand with antibiotics then it shouldn't hurt at all, but if infection is present it prevents full numbness. Just speak up I guess if you're not numb enough and your dentist will give you another shot. I think the worst bit for you will be keeping your mouth open for so long, jaw feels stiff after, but other than that you'll be fine I'm sure - no worries. Plus it's easier to complete treatment on a front tooth as it's more accessible and has only 1 nerve. Good luck - hope it goes well. And I sympathise I'm also getting wisdom teeth through right now and not only does it throb, mine too are coming in at all sorts of funny angles.
I guess they've got to go.