I had a root canal & crown put in 2000. In jan 2011 I began having issues with that front upper tooth, an Odor was coming from it and a metal taste. I had a re-root canal done and was put on antibiotics for an infection that spread. Smell went away but returned this may 2012. I got a teeth clean & that didnt help. I'm told I have a crack in my crown, I get a new one and a clean. Smell on gum is still there. Bone is decaying, requesting implant to be done but will that help? Whats causing odor?