What is Fluoride Varnish?

Fluoride varnish, technically known as fluoride stannous, is highly concentrated fluoride mixed with a synthetic resin base to create a sealant. The varnish usually contains at least 25 percent fluoride and 71 percent stannous tin. The sealant is applied by a dentist or dental hygienist to the teeth, particularly on the back molars. Fluoride varnish is commonly used on children and adults to protect the teeth from cavities. Studies show the varnish also reduces tooth sensitivity in people with overly sensitive teeth.

Fluoride varnish is painted on the teeth and dries quickly when it comes in contact with saliva. Over a period of time, the fluoride in the varnish is absorbed by the teeth and helps to strengthen and protect them. Dental experts recommend children begin getting the fluoride treatment as early as possible, beginning with the emergence of the first teeth. New applications of the varnish are required from two to four times a year to be effective and provide constant protection.

Increasing risks to children’s dental health have led many U.S. daycare centers and school districts to contract with government-funded programs to provide children with dental check-ups and fluoride varnish treatments. These are usually offered once a year and are free of charge to the parents. A qualified dental hygienist goes to the school during regular hours and applies the varnish to those who have had a permission slip signed allowing for the treatment.

After application, the teeth may appear clear or yellowish in color. The discoloration is temporary and usually goes away after brushing the teeth the day after treatment. Fluoride varnish is considered safe to use because the application and drying processes prevent most of the fluoride from being ingested. Additionally, while the varnish uses a high concentration of fluoride, the amount applied to the teeth is minimal. Many dentists suggest brushing with fluoridated toothpaste at least twice a day, in addition to regular varnish treatments.

Treatment with fluoride varnish is generally not recommended for people living in areas where the water is fluoridated. Fluoridation occurs when fluorides or fluoride salts are added to the city’s main water supply. Some communities fluoridate the water to prevent dental issues and to eliminate the need for varnish or other treatments. Although the risk is minimal because of the small amounts of fluoride used in varnish and added to the water supply, fluoride poisoning may occur. Signs of fluoride poisoning from routine varnish applications include an unusual taste with salivation and thirst, abdominal pain or nausea and vomiting, muscle weakness and shock.