Fluoride Varnish: What Is It and What Is It Used for in Children?

Fluoride varnish is a dental product that helps prevent or treat cavities in children. We'll tell you everything you need to know.
Fluoride Varnish: What Is It and What Is It Used for in Children?

Last update: 16 July, 2022

Cavities are one of the most prevalent diseases during childhood, and the use of fluoride offers great benefits in preventing them. It’s even capable of reversing them in their early stages. There are different ways to incorporate this mineral and take advantage of its benefits, among which is the fluoride varnish that’s applied directly on tooth surfaces.

When you visit your pediatric dentist, the professional may suggest you use this product, and that’s why in this article, we’re going to tell you all about it in detail. Don’t miss it!

What’s fluoride and how does it work?

Before telling you about flouride varnish, let’s take a closer look at some important aspects of fluoride. It’s a natural mineral present in some foods, such as fish, green leafy vegetables and cabbage, grapes, wheat, rice, tea, and water.

In addition, fluoride is present as an ingredient in several edible or drinkable products. Therefore, many communities take advantage of its preventive action against cavities and add it to tap water, milk, or table salt.

It’s also part of the components of several household oral hygiene products, such as toothpaste, dental floss, and mouthwash. There are even special materials and presentations used by the dentist in the dental office to prevent or treat cavities.

Fluoride is able to combine with other minerals in the body and strengthen teeth and bones. In teeth, for example, it combines with enamel crystals to increase their resistance to decalcification.

The presence of fluoride in the oral environment inhibits the adhesion of germs to one another, which hinders the formation and accumulation of bacterial plaque. It also reduces the metabolism of bacteria and decreases the production of acids that are harmful to teeth.

A toddler brushing her teeth.
Children should use fluoride toothpaste with every toothbrushing but sometimes this alone isn’t enough. Therefore, consult your pediatric dentist to ensure the best care for your children’s teeth.

Sources of fluoride

The incorporation of fluoride into the body takes place in two main ways:

  • Systemic: The mineral is ingested and distributed through the body via the blood. Once in the mouth, it’s deposited on the forming dental structures and increases their resistance. In other words, it’s a key source in infants and young children.
  • Local: This is carried out on the teeth that have already erupted and are in the mouth. Fluoride comes from pastes, dental floss, and rinses used at home, or materials, varnishes, or gels applied by a dentist.

What’s fluoride varnish?

Fluoride varnish is a dental product that’s applied to the teeth to prevent cavities. It also helps to stop and reduce them so that they don’t worsen.

It’s a lacquer with a creamy consistency, yellow color, and pleasant taste, containing high concentrations of fluoride.

With the placement of fluoride varnish on the enamel, the combination of this element with other minerals in the teeth is promoted. This way, the treated element gains resistance to the action of bacterial acids and, in the case of cavities, allows remineralization of the tooth structure.

What’s fluoride varnish used for in children?

As we’ve already mentioned, fluoride is capable of reducing the development, proliferation, and metabolism of bacteria in the mouth, which reduces the degree of acidity that’s harmful to the teeth. In addition, when combined with the other minerals in the enamel, they make it even more resistant.

In cases where the carious process has already begun, fluoride can stop the loss of hard tissue and promote remineralization. This occurs because it’s incorporated into the tooth structure through the formation of new fluorapatite crystals.

Therefore, as we’ve already told you, fluoride varnish is used to prevent or treat cavities in children. Its main advantage is that due to its consistency, it prolongs the contact time between the mineral and the tooth enamel and thus acts as a slow-release reservoir.

According to data obtained from a review conducted by the Cochrane Collaboration Oral Health Group:

“Children and adolescents who receive periodic treatments with fluoride varnishes suffer 43% less new cavities in permanent teeth and 37% less in deciduous teeth”.

Indications for fluoride varnish

Pediatric dentists usually resort to this easy, convenient, and effective treatment in those cases in which the little ones have a high or very high risk of cavities. Here are some specific cases:

  • Children for whom brushing and flossing become difficult. For example, children with disabilities, behavioral problems, or lack of cooperation.
  • Children who are at high risk of developing cavities because they have orthodontics, suffer from dental crowding or malpositioning, maintain a high consumption of sweets, or have a low salivary production.
  • Infants with heart, immunity, or blood clotting problems. In these cases, the development of cavities increases the risk of suffering serious systemic complications.
  • Infants with active cavities or with a history of having suffered the disease.

How is fluoride varnish applied to children’s teeth?

The application of fluoride varnish on children’s teeth is very easy and comfortable, both for the patient and for the professional.

It consists of painting the surface of the teeth with a small brush containing the material. It resembles the way nails are painted with nail polish. Therefore, the process only takes a few minutes and doesn’t hurt at all.

Fluoride varnish is sticky, and once applied, it comes in contact with saliva and hardens quickly. Once it’s in place, the child can feel the presence of the material on their teeth but can’t remove it.

Most brands market the product with a yellowish coloration that’s evident at the time of application. But this stained appearance is temporary and disappears after a few hours or after the first brushing. Currently, transparent varnishes are being developed to avoid this inconvenience.

A girl at the dentist.
Treatment with fluoride varnish in children is safe, as the doses applied are minimal. It even protects children’s teeth for several months. However, the results improve if the process is repeated at least every 3 or 4 months.


Once your pediatric dentist has applied the fluoride varnish to your child’s teeth, there will be certain care that you should consider in order for the treatment to be successful:

  • Your child can eat and drink when leaving the dental office, but very hard, hot, sticky, or acidic foods should be avoided.
  • Teeth shouldn’t be brushed or flossed for at least 4 to 6 hours. In most cases, it’s best to wait until the next day to re-sanitize the mouth.
  • When your child brushes their teeth again, they should be asked to spit and avoid swallowing the paste or saliva.
  • The rest of the guidelines and care indicated by the dentist in the dental office should be followed.

Keep in mind that although fluoride varnish is an excellent preventive measure against cavities, it’s not enough by itself. It’s always necessary to maintain other simple but important care, such as brushing and dietary care.

Taking care of your child’s oral health and taking them to the pediatric dentist on a regular basis are the best strategies to keep their mouth healthy.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Alberti, Y., Diana, B., de Gouveia, M., & Molin, L. (2020). Agentes fluorados en la terapia de remineralización en niños: revisión sistemática. Revista de Iniciación Científica6.
  • Marinho VCC, Worthington HV, Walsh T, Clarkson JE. Fluoride varnishes for preventing dental caries in children and adolescents. Cochrane Database of Systematic Reviews 2013, Issue 7. Art. No.: CD002279. DOI: 10.1002/14651858.CD002279.pub2
  • Perona, M. D. P. G., Gálvez, D. A., & Salinas, C. T. (2021). Novedades en el uso del barniz de flúor. Reporte de caso. Revista de Odontopediatria Latinoamericana3(2), 111-117.
  • Santamaría García, R. A., Mendoza Ibáñez, A. J., & Maldonado Avelar, E. C. (2016). Comparación de la efectividad en la remineralización de la lesión inicial de caries dental utilizando dos protocolos de aplicación y dos marcas de flúor barniz al 5%.
  • Casals Peidró, E., & Pereiro, G. (2014). Guía de práctica clínica para la prevención y tratamiento no invasivo de la caries dental. RCOE. Revista del Consejo General de Colegios de Odontólogos y Estomatólogos de España, 2014, vol. 19, num. 3, p. 189-248.
  • Colque Huasco, R. Uso del barniz de flúor en escolares a nivel preventivo (Doctoral dissertation).
  • Montaño Forero, A. C., Rangel Monroy, A. A., & Rodríguez Moreno, M. L. (2019). Flúor y su relación con estructuras dentales: un análisis bibliométrico.
  • Plaza Pedraza, C. L. (2021). Evaluación remineralizante de diferentes barnices de uso en odontopediatría con liberación de calcio y fluoruro en esmalte desmineralizado. Estudio in vitro (Bachelor’s thesis, Quito: UCE).

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.