The most popular in-office treatment is fluoride varnish, a resin-based fluoride. Various types are available. Fluoride varnish is primarily used to prevent tooth decay by entering the tooth enamel and making the tooth surface impenetrable. The mode of action involves calcium fluoride being deposited on the tooth surface with the formation of fluorapatite.59-69 The varnish is applied after cleaning and drying the tooth surface. For caries protection, fluoride varnish is painted onto the tooth surfaces with a small brush. The varnish forms a sticky covering over the tooth and becomes hard as soon as saliva in the mouth touches it. Fluoride varnish prevents new cavities from forming and slows down or stops decay from progressing.
Many practitioners have begun using fluoride varnish as a desensitizing agent by applying the varnish to the exposed area to seal the dentin surface. Pashley et al., evaluated a series of commercial cavity varnishes and reported that all cavity varnishes tested decreased dentin permeability by 20 to 50%.61 In 2012, Camilotti et al. conducted a randomized, split-mouth clinical trial in 42 patients (252 teeth) presenting with dentin hypersensitivity to thermal changes in the mouth. The treatment groups were 4 fluoride varnishes (Duraphat, Fluorniz, Duofluorid Xii, and Fluorphat), a neutral fluoride (Flutop), a potassium oxalate gel (Oxa-gel) and a placebo which were all applied 3 different times with a time interval of one week between applications. Sensitivity reduction using air blast and clinical probing was evaluated at the end of 1 week, 2 weeks, 3 weeks and 30 days after the last application. The 4 fluoride varnish groups and the oxalate gel group had significantly lower pain scores compared to placebo at the 30-day reassessment; there were no significant differences between the 5 groups. The neutral sodium fluoride group was not significantly different from placebo, nor was it significantly different from Fluoriniz, Duoluorid XII, or Oxa-gel.60
Fluoride varnish is easy to apply, low-cost and generally safe to use in the mouth, but should not be used if there is an allergy to one of the ingredients in the varnish.