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How do fluorides in drinking water help prevent tooth decay?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — halogen Modern version of the periodic table of the elements.

Fluorides, which are compounds of the halogen element fluorine, help prevent tooth decay through two primary mechanisms at the tooth surface.12

First, fluoride facilitates the attachment of calcium and phosphate ions to the tooth, which promotes the formation of fluorapatite crystals. This process helps to remineralize and strengthen enamel. Second, fluoride present in saliva inhibits the growth and adhesion of bacteria that contribute to tooth decay. It achieves this by blocking specific enzymes, which decreases the production of decay-causing acid and further supports the remineralization of teeth.13

Because of these benefits, water fluoridation is practiced in many regions to optimize dental health, particularly in areas where natural fluoride levels in groundwater are low.145