Evaluation of fluoride release from commercially available fluoride varnishes

Background. The authors conducted a study to evaluate the fluoride released from two fluoride varnishes: Duraphat (Colgate-Palmolive Co., New York) an d Duraflor (Pharmascience Inc., Montreal). Fluoride-release information for these commercially available dental products has not been available to cli nicians treating children at risk of developing dental caries. Methods. The authors painted enamel slabs from primary molar teeth with 30 milligrams of two varnishes: nine samples received Duraphat, nine received Duraflor and five samples served as controls. The samples were immersed in buffered calcium phosphate solution (pH, 6.0) to simulate the oral environm ent, and the amount of fluoride released was measured weekly for six months . Results. From week 4 to the end of the study, Duraphat released significant ly more fluoride than Duraflor. Duraflor continued releasing fluoride until week 19, while Duraphat released fluoride until week 28. The authors found greater variability in the release of fluoride from the Duraflor samples t han from the Duraphat samples. Two-thirds of the fluoride was released from both products by the end of study. Conclusions. Both varnishes released fluoride for five to six months. Howev er, the two products exhibited differences in their release kinetics. Clinical Implications. These findings show that either of the fluoride varn ishes may maintain a high level of fluoride in plaque fluid around primary teeth over a long period, but that the availability of fluoride may vary am ong tubes of the same product and between the two products themselves.