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The proper amount of fluoride helps prevent and control tooth decay in children and adults. Fluoride works both while the teeth are developing and every day after the teeth have emerged through the gums. Fluoride consumed during tooth development can also result in a range of visible changes to the enamel surface of the tooth. These changes have been broadly termed dental fluorosis.

What is dental fluorosis?

Dental fluorosis is a condition that causes changes in the appearance of tooth enamel. It may result when children regularly consume fluoride during the teeth-forming years, age 8 and younger. Most dental fluorosis in the U.S. is very mild to mild, appearing as white spots on the tooth surface that may be barely noticeable and do not affect dental function. Moderate and severe forms of dental fluorosis, which are far less common, cause more extensive enamel changes. In the rare, severe form, pits may form in the teeth. The severe form hardly ever occurs in communities where the level of fluoride in water is less than 2 milligrams per liter.

What causes dental fluorosis?

Dental fluorosis is caused by taking in too much fluoride over a long period when the teeth are forming under the gums. Only children aged 8 years and younger are at risk because this is when permanent teeth are developing; children older than 8 years, adolescents, and adults cannot develop dental fluorosis. The severity of the condition depends on the dose (how much), duration (how long), and timing (when consumed) of fluoride intake.

Increases in the occurrence of mostly mild dental fluorosis were recognized as more sources of fluoride became available to prevent tooth decay. These sources include drinking water with fluoride, fluoride toothpaste—especially if swallowed by young children—and dietary prescription supplements in tablets or drops (particularly if prescribed to children already drinking fluoridated water).

What does dental fluorosis look like?

  • Very mild and mild forms of dental fluorosis—teeth have scattered white flecks, occasional white spots, frosty edges, or fine, lacy chalk-like lines. These changes are barely noticeable and difficult to see except by a dental health care professional.
  •  Moderate and severe forms of dental fluorosis—teeth have larger white spots and, in the rare, severe form, rough, pitted surfaces.
Image of normal tooth with semi-translucent structure and smooth, glossy, pale cream color.
Image of questionable fluorosis. Teeth show some slight differences from normal translucent appearance. Some white spots are apparent but not enough to warrant a diagnosis of very mild fluorosis.
Very mild
Image of very mild fluorosis. Teeth with small, paper-white opaque spots over a small area.
Image of mild fluorosis. Teeth show white opaque areas covering an extensive portion, but not as much as 50%, of the total surface.
Image of moderate fluorosis. All surfaces of teeth affected with opaque areas and teeth show marked wear and brown staining.
Image of severe fluorosis. All enamel surfaces of teeth are affected and the teeth do not exhibit normal development. The teeth are pitted and brown staining is also apparent.

What can parents and caregivers do to reduce the occurrence of dental fluorosis?

Know the fluoride concentration of your drinking water

You should know the fluoride concentration in your primary source of drinking water, especially if you have young children. This information should help with decisions about using other fluoride products, particularly fluoride tablets or drops that your physician or dentist may prescribe for your young child. Fluoride tablets or drops should not be used at all if your drinking water has the recommended fluoride concentration of 0.7 mg/L or higher.

If you live in a state that participates in CDC's My Water's Fluoride, you can find out your water system's fluoridation status online. If you are on a public water system, you can call the water utility company and request a copy of the utility's most recent Consumer Confidence Report.

For very young children, less than 2 years old:

Do not use fluoride toothpaste unless advised to do so by your doctor or dentist. You should clean your child's teeth as soon as the first tooth appears by brushing without toothpaste with a small, soft-bristled toothbrush and plain water.

For children aged 2 to 6 years:

Apply no more than a pea-sized amount of fluoride toothpaste to the brush and supervise their tooth brushing, encouraging the child to spit out the toothpaste rather than swallow it. Until about age 6, children have poor control of their swallowing reflex and frequently swallow most of the toothpaste placed on their brush.

See Brush Up on Healthy Teeth for further guidance.

Use an alternative source of water for children aged 8 years and younger if your primary drinking water contains greater than 2 mg/L of fluoride.

In some regions of the United States, public water systems and private wells contain a natural fluoride concentration of more than 2 mg/L; at this concentration, children 8 years and younger have a greater chance for developing dental fluorosis, including the moderate and severe forms. These children should have an alternative source of drinking water that contains fluoride at the recommended level.

What can health care and public health professionals do to reduce the occurrence of dental fluorosis?

Counsel parents and caregivers regarding use of fluoride toothpaste by young children
Parents or caregivers should be counseled on the use of fluoride toothpaste by young children, especially those younger than 2 years. There is an increased chance for dental fluorosis for children younger than 6 years, and especially for those younger than 2 years, because they are more likely to swallow the toothpaste than older children.

For children younger than 2 years, you should consider the fluoride level in the community drinking water, other sources of fluoride, and factors likely to affect susceptibility to tooth decay when weighing the risk and benefits of using fluoride toothpaste. When assessing the risks and benefits, determine if the child may be at high risk for tooth decay because of factors such as poor hygiene, poor diet, or history of decay in the child, and in their siblings or parents.

Target mouth rinses to children at high risk for developing tooth decay
Because fluoride mouth rinses have resulted in only limited reductions in tooth decay among children, especially as their exposure to other sources of fluoride has increased, their use should be targeted to individuals and groups at high risk for decay.

Children younger than 6 years should not use a fluoride mouth rinse without parents first consulting a dentist or physician because there is a possibility for dental fluorosis if these rinses are repeatedly swallowed.

Prescribe fluoride supplements judiciously
Fluoride supplements can be prescribed for children at high risk for tooth decay and whose primary source of drinking water has a low fluoride level. If the children are younger than 6 years, however, then the dentist or physician should weigh the risks for developing decay without supplements with the possibility of developing dental fluorosis. Access to other sources of fluoride, especially drinking water, should be considered when determining this balance. Parents and caregivers should be informed of both the benefits and risks of fluoride supplements.

Fluoride supplements can be prescribed for persons as appropriate or used in school-based programs. When practical, supplements should be prescribed as chewable tablets or lozenges to maximize the topical effects of fluoride.

The prescription dosage of fluoride supplements should be consistent with the schedule established by the American Dental Association (ADA) Council on Scientific Affairs.

Is my child at increased risk of fluorosis if they are being fed infant formula?

Three types of infant formula are available in the United States: powdered formula, which comes in bulk or single-serve packets, concentrated liquid, and ready-to-feed formula. Ready-to-feed formula contains little fluoride and does not cause dental fluorosis. The kinds of formula that must be mixed with water—powdered or liquid concentrates—may increase the chance of dental fluorosis if they are the child's main source food and if the water is fluoridated. More information is available at Infant Formula.