Fluoride is a naturally occurring substance that is essential to the development of strong, healthy teeth in children and vital to the prevention of cavities in fully developed teeth. A balanced diet that does not include fluoridated water will not provide enough fluoride to meet the needs of a growing child or full grown adult.
There are two ways that fluoride helps to strengthen teeth. First, when young teeth are forming under the gums, fluoride (consumed either as fluoridated water or fluoride supplements) becomes part of the developing enamel, making it stronger and more resistant to cavities. Next, fluoride has a significant effect on the outside surfaces of the teerh. Topical fluoride (either as toothpaste or professionally applied fluoride treatments) reduces the breakdown of enamel and heals small carious lesions.
Please visit the ADA Website for more information about fluoride.