When your saliva has fluoride in it from sources like toothpaste or water, your teeth are able to take it in. Sugars and acids from the foods and beverages we consume can attack this enamel layer, demineralizing it and eventually leading to cavities if not treated. The Chemistry Of Dentistry Created By Andy Brunning For Chemical Engineering News Via Compound Interest Dentistry Chemistry Classroom Science Chemistry Fluoride kills bacteria that make lactic acid from sugar by reacting with the bacteria’s cell membrane and the bacteria leak their guts and die. How does fluoride work on teeth chemistry . Fluoride does not remineralize the teeth. And sugary foods in the mouth are an ideal breeding ground for bacteria that cause diseases of the teeth and the periodontium. Fluoride protects teeth from decay. How does fluoride work in the fight against tooth decay? But fluoride can help even after your teeth are formed. Bacteria, like all living things, need food. Also, te...