Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Fluoride varnish is a highly concentrated form of fluoride which is applied to the tooth''s surface, by a dentist, dental hygienist or other health care professional, as a type of topical fluoride therapy. 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, remineralise the tooth surface and to treat dentine hypersensitivity. Fluoride varnishes are relatively new in the United States, but they have been widely used in western Europe, Canada, and the Scandinavian countries since the 1980s as a 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. 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.