I had a root canal and crown on one of my teeth. A few years ago this crown broke off and I never had it replaced. Last night my gum was swollen and Nub was loose. Went to the ER last night. He have me antibiotics and sent me home. When I got home I pulled it out, but I think some of the decayed tooth is left under the gums. Will it cause any future problems if I just leave it? If not what are the possible consequences?