Bad breath that refuses to go away is NOT about your mouth (unless you have serious dental decay); it's your intestinal track and I'd bet my last dime you have parasites. My son suffered from terrible bad breath for years until I finally convinced him to go for colonic Irrigation (no small feat to convince a 12 year old boy to do). We could see the larvea in the colonic tube. He went for 10 colonics and I put him on an anti parasitic herbal product. He's never had a problem since. Most US doctors are not well schooled in parasites; where as doctors in countries of S. America or other more rural countries often think of parasites first when they see illness. Here, most doctors and labs wouldn't even find the parasite...so, fwiw; if you haven't tried this avenue for a cure, I highly suggest you do.