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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.
Fluoride varnish is composed of a high concentration of fluoride as a salt or silane preparation in a fast drying, alcohol and resin based solution.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.
- Although it is not necessary to do a professional prophylaxis prior to the application of a fluoride varnish, it is recommended that the teeth be cleaned with a toothbrush.
- Wiping with a cotton gauze is adequate in cases where there is no heavy plaque or debris.
- The teeth should be lightly dried with air or a cotton gauze.
- The varnish will adhere even if the teeth are moist.
- Isolate the teeth (e.g. with cotton rolls) to prevent recontamination with saliva
- A small amount of varnish (e.g. 0.5ml) is dispensed. The entire dentition may be treated with as little as 0.3-0.6 ml.
- Some manufacturers offer individual dose systems which come with their own varnish filled well.
- A small brush or applicator is then used to apply the varnish
- The varnish will set on contact with the slightly moist teeth
- The patient is instructed to avoid brushing for the rest of the day. Normal oral hygiene procedures can begin again the following day.
- As a result of the time needed for frequent reloading of the brush/applicator, Hodgson (2005) has suggested an alternative technique utilizing a 5 ml plastic syringe. This method allows a more efficient application of the varnish which can be particularly useful in cases where speed is important, such as with a difficult pediatric patient.
- In order to be effective in decay prevention the varnish should be reapplied at least twice yearly.
Advantages and disadvantages
- Fluoride varnishes are available in different flavours which can be advantageous when treating younger patients
- They do not have the bitter taste of some fluoride gels, but in some patients the taste of the varnish can cause nausea especially when consuming food within the 24 hours post treatment.
- They are easily and quickly applied
- They dry rapidly and will set even in the presence of saliva
- Because they do not require the use of fluoride trays they are suitable for use in patients with a strong gag reflex (See image to the right)
- Due to the small amounts used and the rapid setting time there is only a small or negligible amount of fluoride ingested
- Application requires very little equipment and so it can be applied in settings where a dental operatory is not available 
- It has a sticky consistency which helps it to adhere to the tooth’s surface thereby allowing the fluoride to stay in contact with the tooth for several hours
- Based on published findings, professionally applied fluoride varnish does not appear to be a risk factor for dental fluorosis, even in children under the age of 6. This is due to the reduction in the amount of fluoride which may potentially be swallowed during the fluoride treatment because of the small quantities used and the adherence of the varnish to the teeth.
- Due to the colour and adherence of most fluoride varnishes they may cause a temporary change in the surface colour of teeth as well as some filling materials. As the varnish is worn away by eating and brushing the yellowish colour fades. 
Indications and contraindications
Indications for use
- Use as a topical fluoride agent on moderate and high-risk patients, especially children 5 and younger
- Desensitizing agent for exposed root surfaces
- Fluoridated cavity varnish
- Fluoride treatment for institutionalized patients or in other situations where setting, equipment and patient management might preclude the use of other fluoride delivery methods
- Caries prevention on exposed root surfaces
- Fluoride application around orthodontic bands and brackets (See image to right)
- Fluoride treatment on patients when there is a concern that a fluoride rinse, gel or foam might be swallowed
Contraindications for use
- Areas with open cavities
- Patients that are at low-risk or are decay-free and live in an area where the water is fluoridated
- Treatment of areas where discoloration after treatment may be an aesthetic concern 
- Dental caries
- Fluoride therapy
- Dental fluorosis
- Dentin hypersensitivity
- Dental restoration
- Dental surgery
- Weintraub JA, Ramos-Gomez F, Jue B, Shain S et al. (2006). Fluoride Varnish Efficacy in Preventing Early Childhood Caries, Journal of Dental Research, 85(2)
- Centers for Disease Control and Prevention, Department of Health and Human Services. (2007). Other Fluoride Products. Page accessed 17 February, 2008
- Donly K.(2003). Fluoride varnishes. J Calif Dent Assoc, 31(3):217–9
- Marya, C and Dahiya V. Fluoride Varnish: A Useful Dental Public Health Tool, The Internet Journal of Dental Science 2007;4(2). Page accessed 17 February, 2008.
- American Dental Association Council on Scientific Affairs. Professionally applied topical fluoride: Evidence-based clinical recommendations, Journal of the American Dental Association. 2006; 137: 1151-9. Page accessed 17 February, 2008.
- Hodgson, B. (2005). An alternative technique for applying fluoride varnish. Journal of the American Dental Association. 136: 1295-1297
- Salama, FS, Shulte KM, Iseman MF and Reinhardt JW. (2006). Effects of Repeated Fluoride Varnish Application on Different Restorative Surfaces. The Journal of Contemporary Dental Practice, 7(5).