Fluoride is currently conceived as acting for the most part topically, reducing dissolution and enhancing remineralization of the enamel. The introduction of small amounts of fluoride into the mouth as often as possible is therefore important. Regular use of fluoride toothpastes is the most practicable way of maintaining elevated fluoride concentrations at the plaque-enamel interface. The importance of fluoride toothpastes as the basic caries preventive method requires emphasizing. For those who need additional fluoride therapy, frequent rinsing with dilute fluoride solutions or topical applications of concentrated fluoride solutions, gels or varnishes are the commonest alternatives. None of these methods is superior to any other. Thus, choice of method depends on costs, convenience, patient acceptance and safety.