Fluoride is one of the main ingredients of modern toothpasteand has a proven record of preventing dental decay, especiallyamong children. The history, need and development ofadding fluoride based inorganic compounds in the toothpastefor preventing dental decay is presented in this article. Thefine balance required for maintaining healthy teeth and at thesame time preventing dental and skeletal fluorosis by controllingthe amount of fluoride intake is discussed. The chemistrybehind prevention of dental decay by fluoride in relationto the minerals hydroxyapatite and fluorapatite is presented.The requirement of soluble calcium in the diet and its role inremoving excess fluoride when consumed is highlighted.