This document discusses fluoride and its role in pediatric dentistry. It begins by outlining the mechanisms of action of fluoride, including both pre-eruptive and post-eruptive effects. The main caries preventive mechanisms are through post-eruptive or topical effects, where fluoride is incorporated during remineralization to make enamel less soluble. The document then discusses various methods of fluoride application in pediatric dentistry, including professionally-applied and self-applied topical fluoride treatments as well as silver diamine fluoride and systemic fluoride.