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. 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, 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.
A panel of experts convened by the American Dental Association (ADA) Council on Scientific Affairs presents evidence-based clinical recommendations regarding professionally applied, prescription-strength and home-use topical fluoride agents for caries prevention. The panel recommends the use of 2.26 percent fluoride varnish for people at risk of developing dental caries. As part of the evidence-based approach to care, these clinical recommendations should be integrated with a practitioner's professional judgment and the patient's needs and preferences.
Types of Varnish
Commonly used varnishes include MI Varnish, Clinpro White, and Enamel Pro. Different varnish products release varying amounts of calcium, inorganic phosphate, and fluoride ions. MI varnish releases the most amounts of calcium ions and fluoride. Enamel Pro varnish releases the most amount of inorganic phosphate ions. Each type of varnish is designed to be used in specific situations.
Fluoride varnish treatment has a better outcome at preventing caries at a lower cost compared to other fluoride treatments such as the fluoride mouth rinsing. For fluoride varnish treatment, the benefit to cost ratio 1.8:1, whereas fluoride mouth rinsing is 0.9:1. With fluoride varnish treatments, one can save by preventing future restorations. Fluoride varnish also requires fewer treatments for measurable effectiveness, therefore in the long run it is cost effective when compared to other treatments.
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.
- Fluoride varnish treatments are shown to reduce the number of the cariogenic bacteria S. Mutans by over ten-fold.
- Fluoride varnish was a higher concentration than the foam and gel. There was not a significant difference in the amount of remineralization between gels, foams, and varnish. A study with a larger sample size and a longer time frame could show differing results.
- Due to the color and adherence of most fluoride varnishes, they may cause a temporary change in the surface color of teeth as well as some filling materials. As the varnish is worn away by eating and brushing, the yellowish colour fades.
- Varnish costs more than gel and requires a prescription unlike the gel that's over the counter.
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
- When a higher concentration of fluoride is needed for high caries risk patients
- In the elderly to prevent increasingly prevalent root dentin lesions, which may require higher concentration of fluoride
- On advanced enamel carious lesions, which may also require higher fluoride concentration for remineralization 
- 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
- Remineralization of lesions in root dentin
- 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 
Safety of Fluoride Varnish
The safety of fluoride varnish leads to questions of toxicity due to ingestion during treatment. From a number of different studies conducted it was concluded that the risk of acute toxic reactions was minimal. There are also very few instances of any type of allergic reactions to fluoride varnishes that would contribute to the safety of an individual. Currently the use of fluoride is typically safe and is being sent for approval by the FDA as a caries-preventative agent.
- 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. doi:10.14219/jada.archive.2005.0347.
- Marinho, VC (2013). "Fluoride varnishes for preventing dental caries in children and adolescents". Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD002279.pub2. PMID 23846772.
- NJ Cochrane, P Shen, Y Yuan, EC Reynolds (Mar 2014). "Ion release from calcium and fluoride containing dental varnishes". Aust Dent J 59 (1): 100–5. doi:10.1111/adj.12144.
- Skold, UM (Oct 2008). "Cost-analysis of school based fluoride varnish and fluoride rinsing programs". Acta Odontol Scand 66 (5): 286–92. doi:10.1080/00016350802293978. PMID 18720049.
- Jeevarathan J, Deepti A, Muthu MS, Ratha Prabhu V, Chamundeeswari GS (2007). "Effecto of fluoride varnish on streptococcus mutans counts in plaque of caries-free children using Dentocult SM strip mutans test: a randomized controlled triple blind study". J Indian Soc Pedod Prev Dent 25 (4): 157–63. doi:10.4103/0970-4388.37010. PMID 18007100.
- Yee YE et al. (2010). "Comparison of remineralization effect of three topical fluoride regimens on enamil initial carious lesions". J Dent 38 (2): 166–71. doi:10.1016/j.jdent.2009.10.002. PMID 19819290.
- Salama, FS; Shulte, KM; Iseman, MF; Reinhardt, JW (2006). "Effects of Repeated Fluoride Varnish Application on Different Restorative Surfaces". The Journal of Contemporary Dental Practice 7 (5).
- Petersson, LG (Mar 2013). "The role of fluoride in the preventive management of dentin hypersensitivity and root caries". Clin Oral Investig.
- Tan HP, Lo EC, Dyson JE, Luo Y, Corbet EF (2010). "A randomized trial on root caries prevention in elders.". Journal of Dental Research 89 (10): 1086–90. doi:10.1177/0022034510375825.
- Beltran-Aguilar, E, Goldstein, J, Lockwood S. (2000). "Fluoride varnishes-a review of their clinical use, cariostatic mechanism, efficacy and safety". JADA: 589–596.