It is a common question for which Dr. Chang has already written more comprehensively about here.
But at least in this particular article, he is quoted as saying:
Eating the yogurt, you swish it all around in your mouth while you’re enjoying it, and hopefully, you get it to work for your mouth... If you can breathe through your nose but use your mouth out of habit, especially when you sleep, a chin strap might help. It lets you get used to keeping your mouth shut in bed or around the house until it becomes second-nature.Read the full story here.
Natural and Home Remedies for Bad Breath. WebMD.com. Accessed 4/16/16.