Just throwin it out there since this relates to bad breath in general and at least in part relates to dental hygiene. A co-worker of mine from several years ago once went through a period of several months during which various people close to him at work, including myself, had politely voiced an observation with him - his breath was reeeeeealy bad, not just bad in an ordinary way, but bad in a way like standing 10 feet away from him and it could still be detected as bad so long as he was breathing/exhaling in the general direction of somebody else. It took me a good several weeks to work up to how to go about being as gentle and delicate as I could in expressing this concern with him. When I did, he took it well, I think in part because he'd heard it many times before, especially, as he pointed out, from his spouse and kids. He explained how his dentist explained to him that he needed to have what is generally referred to as "deep" or Curetage cleaning of his teeth and gums. I've never had one of these and based on his description hope that I never have the need to. When he had this done, they did it in a quadrant by quadrant fashion, to it took four visits total. He described how this was a very painful process, I guess they scrape a lot farther and deeper than they normally do with routine surface cleaning. Whatever was done, it worked, at least, it worked well enough for somebody like myself who had definite limits on just how close I was willing to get to him (or anyone else as far as this goes ;) The ten feet away effect had definitely been cleaned up.