[Fluoride release properties of GRACs. A survey of the literature]

While numerous publications have documented the anticariogenic properties of GPACs through fluoride release measurements and artificial caries studies, considerable debate still exists concerning the fluoride release properties of these materials in terms of dissolution and diffusion mechanisms. This paper will review some of the more important aspects of GPAC fluoride release. Numerous studies have reported on the fluoride release properties of GPACs. The first point to note is that all the studies were performed on commercial materials. This approach has inherent difficulties as the main factor governing fluoride release is the GPAC composition and formulation. Traditional GPACs are two component systems, consisting essentially of a ion leachable fluoroaluminosilicate glass and a polymeric acid, especially a polycarboxylic acid; fluoride ions are of prime importance in this reaction, in that they have a major influence on the structure of the glass, its reactivity, cement formation and bioactivity. GPACs may be viewed as particle reinforced polymeric composites, in which the degraded residual glass particles with their silicious layer reinforce the polysalt matrix, improving mechanical properties.