Although the prevalence of caries has declined in young persons in developed countries, there is still a need for water fluoridation. The effectiveness of fluoride is dependent on the ambient levels of fluoride in the oral cavity. Fluoride appears to exert the bulk of its protective effect locally by promoting remineralization of early carious lesions. Nevertheless, fluoride tablets continue to be prescribed as if the action of fluoride is expressed systemically. There is an urgent need to explore the clearance of fluoride from the mouth and to develop methods to ensure constant levels of fluoride in the oral cavity, thereby reducing both the need for frequent exposure and the amount necessary for clinical effect.