Fluoride is a mineral that occurs naturally in many foods and water. Every day, minerals are added to and lost from a tooth's enamel layer through two processes, demineralization and remineralization. Minerals are lost (demineralization) from a tooth's enamel layer when acids -- formed from plaque bacteria and sugars in the mouth -- attack the enamel. Minerals such as fluoride, calcium, and phosphate are redeposited (remineralization) to the enamel layer from the foods and waters consumed. Too much demineralization without enough remineralization to repair the enamel layer leads to tooth decay.
Fluoride helps prevent tooth decay by making the tooth more resistant to acid attacks from plaque bacteria and sugars in the mouth. It also reverses early decay. In children under six years of age, fluoride becomes incorporated into the development of permanent teeth, making it difficult for acids to demineralize the teeth. Fluoride also helps speed remineralization as well as disrupts acid production in already erupted teeth of both children and adults.
Even though there's no scientific studies to suggest that people who drink bottled water are at increased risk of tooth decay, the American Dental Association (ADA) says that such people could be missing out on the decay-preventing effects of optimally fluoridated water available from their community water source. The ADA adds that most bottled waters do not contain optimal levels of fluoride, which is 0.7 to 1.2 parts per million (this is the amount that is in public water supplies, in the communities that have fluoridated water). To find out if your brand of bottled water contains any fluoride, check the label on the bottle or contact the bottle water manufacturer.
Fluoride can make your teeth stronger and reduce the risk of developing cavities. The preventive potential of fluoride is one of the major advances in dentistry in the last century.
But how much is enough? If you haven't had cavities in the last few years, the combination of brushing with fluoride toothpaste twice daily and drinking optimally fluoridated water should give you sufficient exposure, according to the January issue of Mayo Clinic Health Letter. Too much fluoride can cause spots on your teeth.
But if you're at higher risk having had cavities recently, a water supply with low fluoride or a problem such as dry mouth that can lead to tooth decay your dentist also may recommend using fluoride treatments at home or a professional application of fluoride gel two to four times a year. Fluoride tablets may help young children, but they've not been proven to help adults after enamel has formed.