Back in Jan. of last year I had a root canal done on the tooth behind one of my front ones. I kept getting gum boils afterwards and the dentist just gave me more antibiotics, and said if it continued to come back in a few months. It finally became very painful and I had to go back. They said The tooth in front of the one they did the root canal on, was also infected (the front tooth) and needed a root canal. I did the root canal in oct. and the gum has not gone down all the way (has continued to be swollen, not as bad as before the second root canal) This week though it has really gotten swollen, and a gum boil is starting to form like before. It is once again starting to become painful.

Am I right to think this should not still be happening? after two root canals?

I am asking what could still be causing this, should I still trust the dentist? and any advice on what should be done.

Thanks!