About Dental Fluorosis

Key points

  • Fluoride prevents cavities (tooth decay).
  • Consuming too much fluoride when teeth are growing may lead to dental fluorosis, a change in how teeth look.
  • Only young children can develop dental fluorosis.


When teeth are growing under a child's gums, some fluoride they consume is combined with the outer enamel layer of teeth. This usually makes teeth stronger and less likely to get cavities.1 Too much fluoride while teeth are growing can affect the appearance of teeth when they come in. The outer enamel layer may have white flecks, spots, or lines.

By about age 8, the enamel of permanent teeth is fully formed. Older children, teens, and adults cannot get dental fluorosis. How obvious these changes in teeth are depends on how often and for how long a child consumes too much fluoride. While dental fluorosis can be moderate or severe, causing extensive enamel changes, in the U.S., dental fluorosis is mostly mild and cosmetic meaning it does not affect tooth function and is not painful.2 Moderate and severe forms of dental fluorosis are rare.

Other Types of Tooth Discoloration‎

Tooth color can also be affected by infant and early childhood illness and any drugs taken, dental infections of baby (primary) teeth, trauma to the face, and genetics.

Reducing risk

Be careful with products that have added fluoride

Children swallow easily, especially when brushing teeth. For ages 3 to 6, no more toothpaste than the size of a pea should be smeared on a child's toothbrush.2 Before age 3, parents should smear no more toothpaste than the size of a grain of rice on a child's toothbrush.2 For children younger than 2, consult first with your doctor or dentist regarding the use of fluoride toothpaste or other fluoride products. Parents should watch their children and teach them to spit out, not swallow, toothpaste when finished brushing.

For children at high risk of getting cavities, dental providers or pediatricians may recommend other fluoride products. The providers will discuss the risks of dental fluorosis when recommending mouth rinse or supplement use.1

Keep Reading: About Fluoride

How much fluoride is in your water?

Bottled water, tap water, and well water have different amounts of fluoride. Most tap water has fluoride at US Public Health Service recommended levels that best protects teeth from cavities while minimizing dental fluorosis.

If you have children younger than age 8, make sure they aren't getting too much fluoride from your water. If your child drinks tap water without a filter, contact the organization you pay for your water to ask about the amount of fluoride in the water. If your state participates in CDC's My Water's Fluoride, you can find your water system's most recently reported fluoridation status online

If you use a water filter, check with the manufacturer to see if the filter removes fluoride. If your child drinks well water or bottled water, you have to test the water using a state certified laboratory to determine the fluoride amount or contact the bottled water manufacturer to ask the fluoride content of the bottled water.

Community Water Fluoridation‎

The US Public Health Service considered all sources of fluoride intake and recommends that water have 0.7 mg/L of fluoride. This concentration maximizes fluoride's oral health benefits while minimizing risks of harms, such as developing dental fluorosis. Read more at Community Water Fluoridation Frequently Asked Questions.
  1. Centers for Disease Control and Prevention. Recommendations for using fluoride to prevent and control dental caries in the United States. MMWR Recomm Rep. 2001;50(RR-14):1–42.
  2. American Academy of Pediatrics. Dental health & hygiene for young children. Accessed April 22, 2024. https://healthychildren.org/English/healthy-living/oral-health/Pages/Teething-and-Dental-Hygiene.aspx