I had the same tooth worked one on 7 different occasions. First was Cavity, then it got sensitive so second time they took the filling out and replaced it with temp with meds within. Later on I had to get a crown, then it started to hurt so they did a root canal. Then it got infected and I had to take anti-botics to get the swelling down and they find out it had four roots instead of 3 so they had to do another root canal. So by this time I went to a different dentist, they suggested doing another root canal since it was getting infected again, they said that germs might of gotten in there when the last dentist opened it up. I told them to just go ahead and extract the tooth as it was causing too much issue. After extraction, the wound won't heal, there were bone fragments sticking out preventing it to heal. They had to snip off bone fragments on two separate occasions. FINALLY it healed up.....LoL.....That was a problematic tooth!!! Now a different dentist wants to put a bridge up in that area as that missing tooth is causing the tooth on either side to have issues. It never ends...