--- title: "Fluoride Varnish - Safety and Effectiveness" url: "https://www.newmouth.com/oral-health/fluoride-varnish/" description: "Fluoride varnish is a popular treatment for preventing cavities. Read this to learn how fluoride varnish works, how to apply it for the best results, and more." --- ## What is Fluoride Varnish? Tooth enamel is the outermost layer of the tooth and is the hardest substance in the body. However, plaque can make it porous and weak, which can lead to cavities. ![Animation or illustration of a tooth with labels on tooth anatomy including enamel and dentin](/_astro/Animation-or-illustration-of-a-tooth-with-labels-on-tooth-anatomy-including-enamel-and-dentin-1024x1024.WesRZmCr_1pDAFt.webp) ## How Does Fluoride Varnish Work? Professionally applied fluoride varnish is a topical treatment used to prevent tooth decay. It is a clear, sticky gel applied to the teeth with a brush. Although fluoride varnish is typically used for children because their teeth are still developing, it can be used for anyone a dentist thinks may benefit from it. For example, adults with dry mouth or a history of radiation in the head and neck area are at a higher risk for cavities, so many benefit from fluoride varnish. Fluoride varnish increases the resistance of enamel to acid attacks. It also enhances remineralization of the tooth surface. It can: - Strengthen tooth enamel - Reduce risk of cavities - Reduce tooth sensitivity Applying a thin layer of fluoride varnish to the enamel forms a temporary protective barrier. This prevents acid from reaching the tooth surface. It also helps saliva neutralize plaque or bacteria left on the tooth. ## Is Fluoride Varnish Safe? According to resident expert Dr. Khushbu Aggarwal, fluoride varnish is considered safe when used appropriately. Fluoride varnish is considered a low-risk treatment. Only a small amount is used during application, so you are unlikely to swallow much fluoride. Speak to a dental professional if you or your child receives fluoride in other forms, such as: - Drops - Tablets - Toothpaste They may advise stopping the additional fluoride for a few days before and after treatment. Alternatively, they may determine fluoride varnish is unsuitable for your situation. ### Effectiveness According to the Centers for Disease Control and Prevention (CDC), approximately one in five children have untreated tooth decay by age 19.5 The CDC also states that over half of children between the ages of 6 and 8 have had a cavity in at least one of their baby teeth. Additionally, over half of all adolescents aged 12 to 19 have had a cavity in at least one of their permanent teeth. Further research shows that 40% of all children experience tooth decay by the time they reach kindergarten. So it is no surprise that dental professionals recommend fluoride varnish to help prevent tooth decay. A 2013 review evaluated the effectiveness of fluoride varnish in preventing caries in children and adolescents compared to a placebo or no treatment at all. There was a significant reduction in cavities in those treated with fluoride varnish. The evidence suggests a 43% reduction in decayed, missing, and filled tooth surfaces in children and adolescents who received fluoride treatment for their permanent teeth. Additionally, the review looked at trials investigating the effect of fluoride varnish on baby teeth. It found a 37% reduction in decayed, missing, and filled tooth surfaces for children in that group. ### Benefits Many studies have found that fluoride can help [prevent cavities](/blog/how-to-prevent-cavities/) in both children and adults. Additional benefits include: - Varnishes are adhesive, so they make contact with the teeth instantly - They are easy and quick to apply, even in children that are otherwise difficult to treat - Unlike other methods of professional fluoride application, varnishes are relatively inexpensive Fluoride varnish can be applied up to 4 times per year or every 3 months. Studies show that children who get fluoride varnish every 3 months have fewer cavities than those who get it less often or not at all. ### Risks and Potential Side Effects Fluoride varnishes can leave the teeth temporarily discolored, although this will go away after the varnish has been brushed off the next day. Because varnishes can be very sticky, Dr. Aggarwal advises using a disposable toothbrush to brush your teeth 24 hours after application. Also, hold off wearing dental appliances until you have brushed the fluoride off your teeth the next day. Fluoride is a chemical compound that has been debated for its use in dental care. Some believe fluoride is toxic and should not be used in any products. Others believe it’s a safe, effective additive to include in toothpaste and water. In excessive amounts, fluoride has been shown to cause spots on teeth and/or stomach upset. ## How to Apply Fluoride Varnish ![Fluoride varnish application workflow v2](/_astro/fluoride-varnish-application-workflow-v2.BEofkcLu_jqJuk.webp) Fluoride varnish is a topical treatment dental professionals apply to the teeth. It contains fluoride, which helps prevent tooth decay and can sometimes treat dental caries. Before application, the dental professional will dry the teeth with gauze. Then, they will paint the fluoride varnish onto all the teeth. ![Dental flouride varnish being applied to a great set of teeth nm 1332](/_astro/dental-flouride-varnish-being-applied-to-a-great-set-of-teeth-nm-1332.DTu-qMb2_Z1vGHe5.webp) Fluoride varnish is sticky, so it adheres well to the teeth. When it comes into contact with saliva, it hardens onto the teeth, allowing it to stay in place. While it is on the teeth, the varnish maintains a high concentration of fluoride on the teeth for several hours. According to the American Dental Association (ADA), this allows fluoride to remineralize the teeth. Dental professionals usually recommend a fluoride varnish application every 3 to 12 months. Some pediatricians are even trained to apply fluoride varnish. This can improve access for people who don’t have regular dental care. ## How Long to Leave Fluoride Varnish on Teeth Typically, people should leave fluoride varnish on their teeth for at least 6 hours. Some brands require the varnish to stay on teeth for 24 hours. Other brands recommend leaving the fluoride on teeth overnight and brushing it off in the morning. ### When Can You Eat After Applying Fluoride Varnish? According to Dr. Aggarwal, the type of fluoride you receive determines when you can eat and drink afterward. For example, after application of a 3M fluoride varnish, you should avoid the following for 4 to 24 hours to maximize the effects: - Hard foods - Hot drinks - Alcohol (including mouthwashes with alcohol) - Brushing - Flossing You can eat soft foods or drink cold drinks right away. ## How Much Does Fluoride Treatment Cost? Some insurance providers will cover the cost of fluoride varnish treatments. This is because it is considered a preventative measure that can promote good oral health. It can also mean saving money in the long run. For example, a filling costs anywhere from [$50 to $300](/dentistry/general/cavity-fillings/) per tooth. Because fluoride varnish reduces the need for fillings, it makes sense to receive the treatment if possible. ## Summary Fluoride varnish is a topical treatment that contains fluoride ions. A dental professional applies it to the teeth to seal the enamel and increase its resistance to acid attacks. Fluoride varnish treatments are used primarily to prevent tooth decay in children and adolescents whose permanent teeth have erupted but have not yet finished developing.