The function of fluoride application in children is mainly to prevent dental caries, or to have a certain remineralization effect on early dental caries, which can prevent dental caries from getting worse. Fluoride ions react with hydroxyapatite in enamel to form fluorapatite, which is more acid-resistant and makes teeth more resistant to dental caries. Now, for some children, fluoride can be applied to the surface of teeth to enhance the anti-caries ability and prevent dental caries, which can make early dental caries have a certain remineralization effect and slow down the speed of dental caries. Therefore, fluoride can be considered to prevent dental caries in clinical children.