Systemic fluorides are those that are ingested into the body and become incorporated into forming tooth structures.4 Systemic fluorides when ingested during tooth development are deposited to some extent throughout the tooth surface. However, the actual mechanism of action of systemic fluorides is from the topical protection as the fluoride present in saliva, which continually bathes the teeth, provides a constant source that is also incorporated into plaque and facilitates remineralization.5 Today the primary source of systemic fluoride in the U.S. is water fluoridation. Other sources include dietary supplements (tablets, drops or lozenges) and fluoride present in food and beverages. Salt and milk fluoridation are more common in other countries around the world, including Europe, Canada, China, South America, and Mexico.