Tooth enamel is hard but also has microscopic pores in it. Sugar combines with the bacteria in plaque, which forms on your teeth daily, to produce acids that seep into the enamel’s pores. This causes the enamel to demineralize and become weak, contributing to the formation of cavities. Fluoride helps prevent tooth decay by slowing the breakdown of enamel and speeding up the natural remineralization process. This keeps your teeth strong and healthy. Fluoride also fights cavities by reducing the amount of acids that are produced by plaque.