In the 1970s, Joseph Tonzetich of the University of British Columbia analyzed human breath for the first time using a gas chromatograph, which separates gases into their individual chemical ingredients. Since then, researchers have found around 150 different compounds in our breath -- some (but not all) of them stinky. The smell of your breath comes mostly from waste produced by bacteria, who dine on the leftover food particles and dead skin in your mouth. The bacteria that live on your teeth are "gram-positive": that is, bacteria with simple cell walls. Gram-positive bacteria are often responsible for wearing down enamel, but don't emit many noxious odors. It's the gram-negative bacteria -- those with impenetrable cell walls -- that live mostly below the gum line and on the tongue which spew the smelliest scents. Bacteria such as Treponema denticola, Bacteroides intermedius, and Porphyromonas endodontalis are the heaviest producers of hydrogen sulfide, which smells like rotten eggs, and some also produce methyl mercaptan, which smells like rotting cabbage. Though other compounds have been detected, it's those two that most studies find to be the cause of the worst morning breath. That means that in order to get fresher breath, you should brush more than just your teeth. We've collected some awesome videos on this topic. Watch them now to learn more.
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Key Facts In This Video
Mouth bacteria aren't all bad. Some cause cavities and gum disease, but others can protect against more dangerous bacteria. 00:27
Your saliva usually keeps bacterial colonies under control, but at night, you don't produce as much saliva. 00:39
Bacteria produce odor-causing compounds as waste products, including hydrogen sulfide, methanthiol, isovaleric acid, and cadaverine. 01:02