Helo.. I stumbled across your posts and am astounded by the fact that no one has suggested flossing...? Honestly, a dentist once said to me that it is amazing how much extra bits of food get lodged inbetween the teeth of adults compared to children, despite the fact that both adult and child have the same diet.
Sadly, I am too lazy to keep up this discipline and consequently I am pretty sure I have chronic halitosis. That and possibly because I am essentially a chimney.
Let me know if it works, 'cos I'd be over the moon to find that I have imparted knowledge...