I had the root canal, did not really help. I saw my dentist and he took xrays, he took pictures with something that I have never seen before. $$$ Not covered by our insurance of course. He used ice cubes, he thumped my teeth with an instrument of torture. Nothing helped.

The Root Canal Dr. gave me some real strong Anti-Biotics after the root canal. Nothing helped me until the Carbamazepine. My Neurologist listened to me, read my summary info and told me to start out with a small dosage (can't remember the dosage). Then I was to increase it until the pain went away. That is a rough summary. I give the Carb. the credit.

I was taking several mg a day and then the TN went away. No warning, no "so long guy" or anything, it left. The Carb. was a bit strong for me, so I just quit it.

Fast forward a few months and the TN came back. I took the Carb. and it went away. So I give the Carb. most of the credit.

I hope it is this next Monday that she is scheduled for the root canal. I would certainly tell the dentist/surgeon about the TN.

I am not sure I helped her even two cents worth, but the TN is really unpredictable for me.
I had two root canals and they were "two part" deals both times. He did half one time, then I had to go back for the completion of the Root Canal. I did not like that, but they may not have a choice.

The Air Force did a root canal on me in the 1970s, took about four hours and when they were finished, they polished the new gold cap with a chain saw. Don't laugh, if you had seen the "finish" on that tooth, you would know what I meant. My last root canal was almost totally pain free (not counting the pain in my wallet).

I hope I understood your question and answered at least part of it.