Fluoride has been shown to be an effective agent for prevention of dental caries. It has also been shown that a major portion of this fluoride deposited onto the enamel by topical treatments is rapidly leached away. This in vitro study suggests that fluorosilanes enhance retention and improve penetration of fluoride in enamel. The efficacy of this treatment seems to lie in its ability to utilize the enamel organic network as a conduit. This network increases the enamel prism surface area accessible to reaction with fluoride. This study demonstrates the effectiveness of silanes as a vehicle to transport fluoride via the organic network to loci best suited for therapeutic effectiveness.