Can i sue my dentist for bad root canal?

OK, after going to a root canal specialist, he told me on a tooth that already had a root canal, that the root canal didn't go all the way to the end of the tooth, and that bacteria and such will develop and i have to have another root canal on the same tooth. My previous dentist was not very good at all, and i'm wondering if i can sue them for all my needless pain and suffering for having to go through this root canal twice on the same tooth. I have spent over $10k on this previous dentist on other teeth too, but i'm mainly just interested in getting reimbursed for the one tooth that i know they didn't do right. I'm worried that whatever i signed before the root canal was some release and i can't get anything from them and they'll just say "well, only 90% of root canals are successful anyways". Way i see it, they didn't do the first one correctly, so is that malpractice of some sort?  more