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Pre-treatment

Your Guide to Fluoride Varnish

Find out how fluoride varnish from your dental team helps protect teeth from decay, what happens during treatment, and who should have it.

3 min read

What is fluoride varnish?

Fluoride varnish is a treatment your dental team paints onto your teeth. It contains a high level of fluoride. It sets quickly when it touches spit (saliva). Then it lets out fluoride slowly over several hours.

Fluoride makes tooth enamel stronger. This helps teeth stand up to the acid that germs make after you eat sugar. It can also help reverse very early signs of decay before they turn into holes. Delivering Better Oral Health (Department of Health and Social Care and NHS England) recommends fluoride varnish for children and for adults at higher risk of decay.

Who should have fluoride varnish?

Delivering Better Oral Health and SDCEP guidance recommend fluoride varnish for:

  • Children aged 3 and over — at least twice a year, as part of routine dental care
  • Children at higher risk of decay — up to four times a year
  • Adults at moderate or high risk of decay — twice a year

Your dental team may also suggest it for:

  • People with a dry mouth (xerostomia)
  • People with tooth roots showing, which may be sensitive or at risk of root decay
  • People having brace treatment with fixed braces

What happens during treatment?

Putting on fluoride varnish is quick and does not hurt at all:

  1. Your teeth are cleaned and dried
  2. The varnish is painted onto all tooth surfaces with a small brush. It is a pale yellow, sticky gel with a pleasant smell.
  3. The varnish sets within seconds when it touches spit (saliva)

After the varnish is put on:

  • Do not eat or drink for at least 30 minutes
  • Do not rinse, spit or brush your teeth until that evening
  • Eat only soft foods that day

Is fluoride varnish safe?

Fluoride varnish has a long, proven safety record when a dental professional puts it on. The varnish has a high level of fluoride. But only a very small amount is used, and very little of it is swallowed.

Swallowing small amounts of varnish during treatment is not harmful. Only a very small amount of varnish is painted on, and less is used for young children. This keeps any swallowing to a minimum.

Most fluoride varnishes contain colophony (a tree resin). A very small number of people are allergic to it. Before treatment, tell your dental team if you or your child have ever reacted to sticking plasters. Also tell them if you or your child have had a severe allergy or asthma that needed a hospital stay. In these cases a varnish containing colophony will not be used. Your dental team will choose another product.

Other ways to prevent decay

Fluoride varnish works best alongside these other steps:

  • Brush twice a day with fluoride toothpaste: last thing at night and at one other time. Use toothpaste with at least 1,000 ppm fluoride.
  • For children aged 0–3, use a smear of toothpaste with at least 1,000 ppm fluoride.
  • For children aged 3–6, use a pea-sized amount.
  • For children over 6 and adults, use toothpaste with 1,350–1,500 ppm fluoride.
  • Spit after brushing, but do not rinse with water. This leaves a layer of fluoride on your teeth to protect them.
  • Cut down on how much sugar you have, and how often. What you eat matters, but how often you have sugar is just as important.
  • Go to regular dental check-ups.

Questions to ask your dental team

  • How often should I or my child have fluoride varnish?
  • Is my child's risk of decay low, moderate or high?
  • Are there other treatments to prevent decay that I should think about as well?

This leaflet is for general information only and does not replace professional dental advice. It is intended to support — not replace — the discussion with your dental team about your individual options, risks, and treatment plan. Treatment outcomes vary between patients depending on individual circumstances. Your dental team will confirm exact fees and what is suitable for your specific circumstances before you agree to any treatment.

Sources

Links checked 18 October 2026.

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For clinicians: Child Dental Exam notes template, Fluoride Varnish Application notes template.

Learn more about dental documentation on our blog or see Nosht pricing.

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