Toothpaste Toothpaste is composed of pulverized glass, sugar and a super toxin. The glass helps wear away the enamel, while the sugar softens the enamel and the toxin kills all the natural flora that lives in the human mouth, allowing foreign bacteria a field day. This is all supposed to prevent cavities, but as you can see, is one of the primary causes of tooth decay and mouth infections.
Mouth wash similarly destroys natural mouth flora.
The problem with this is that while it takes a while for the natural bacteria to re-establish themselves, foreign bacteria are replaced with every breathe and mouthful of food or drink.