Fluoride varnish

Fluoride varnish is a highly concentrated form of fluoride that is applied to the tooth's surface by a dentist, dental hygienist or other dental professional, as a type of topical fluoride therapy.^[1] It is not a permanent varnish but due to its adherent nature it is able to stay in contact with the tooth surface for several hours. It may be applied to the enamel, dentine or cementum of the tooth and can be used to help prevent decay,^[1][2][3] remineralise the tooth surface^{[4][5][non-primary source needed]} and to treat dentine hypersensitivity.^{[6][7][non-primary source needed]} There are more than 30 fluoride-containing varnish products on the market today, and they have varying compositions and delivery systems. These compositional differences lead to widely variable pharmacokinetics, the effects of which remain largely untested clinically.

Fluoride varnishes are relatively new in the United States, but they have been widely used in western Europe, Canada, South Africa and the Scandinavian countries since the 1980s as a dental caries prevention therapy. They are recognised by the Food and Drug Administration for use as desensitising agents, but, currently, not as an anti-decay agent.^[8] Both Canadian and European studies have reported that fluoride varnish is as effective in preventing tooth decay as professionally applied fluoride gel; however, it is not in widespread use for this purpose.^[9]

Fluoride varnish is composed of a high concentration of fluoride as a salt or silane-based preparation in a fast drying, alcohol and resin based solution.^[10] The concentration, form of fluoride, and dispensing method may vary depending on the manufacturer. While most fluoride varnishes contain 5% sodium fluoride at least one brand of fluoride varnish contains 1% difluorsilane in a polyurethane base^[10] and one brand contains 2.5% sodium fluoride that has been milled to perform similar to 5% sodium fluoride products^[11] in a shellac base.