Slow-release fluoride.

The latest evidence supports the concept of frequent applications of relatively low concentrations of fluoride for the elimination of caries, even in situations of high caries challenge. Dental materials exhibit a 'burst effect', and the fluoride release is short-lived. Intra-oral devices in the form of copolymer membranes or glass devices cause an elevation of salivary F levels for up to 2 years in animals and humans and have led to increased F uptake in enamel. Caries reduction has been achieved in rats using the copolymer device, and, at present, human caries trials using the copolymer and glass devices are under way in the USA and Leeds, respectively. These intra-oral devices hold great promise to target financial resources for prevention in groups of the population with high caries levels, in particular low socio-economic groups including ethnic minorities and the handicapped.