Fluoride Supplementation: The Ongoing Debate

Diane L. Markowitz, DMD, PhD

Disclosures

February 08, 2012

In This Article

How Much Fluoride Does This Child Need?

Monitoring fluoride exposure in childhood is important in preserving the effectiveness of fluoride in caries prevention while limiting the risk for fluorosis.[33] Only fluoride ingested while enamel is forming (between birth and 8-9 years of age) will affect permanent teeth and potentially cause fluorosis. The Centers for Disease Control and Prevention (CDC) recommend that children younger than 8 years of age not be exposed to more than 1 mg of fluoride per liter of fluid from combined sources.[34] In assessing a child's need for supplemental fluoride, the clinician must consider all of the child's dietary and nondietary sources of fluoride.

Drinking water. The greatest contribution to an individual's fluoride exposure comes from drinking water, either as a beverage or in food preparation. Therefore, the first question to be answered by the clinician attempting to determine whether a patient is receiving adequate fluoride -- or too much fluoride -- is what the fluoride content of the family's water supply is.

This question can be answered by consulting the local public health department or water utility to inquire about the concentration of fluoride in the drinking water source. This information also can be accessed at the CDC My Water's Fluoride Website. Most US municipalities with negligible natural fluoride in their water sources currently add fluoride to drinking water at 0.7-1.2 ppm.

Fluoride supplements. Current American Academy of Pediatric Dentistry guidelines for supplemental fluoride in children, according to the fluoride content of their drinking water, can be found in the Table.

Table. Dietary Fluoride Supplementation Schedule[35]

Child's Age Fluoride Content of Drinking Water Supplya
  < 0.3 ppm 0.3-0.6 ppm > 0.6 ppm
Birth-6 mo None None None
6 months-3 yr 0.25 mg/day None None
3-6 yr 0.50 mg/day 0.25 mg/day None
6-16 yr 1.0 mg/day 0.5 mg/day None

aThese guidelines may need to be revised if the recent HHS recommendation to reduce fluoridation in drinking water to 0.7 mg/L is adopted.

Fluoride is absent from most bottled water. Families who obtain water from a well should have it tested periodically to determine its natural fluoride level. Currently, the American Dental Association recommends that children older than 3 years living in households with well water with a concentration of fluoride less than 0.6 ppm be given a supplement in the form of drops or lozenges. Children in homes with adequate natural fluoride levels greater than 0.6 ppm should not receive supplemental fluoride.

Infant formula. Ready-to-feed liquid infant formulas contain less than 0.21 ppm of fluoride.Infants 3-9 months of age who drink reconstituted infant formula from powdered formula (which includes fluoride) prepared with fluoridated water containing more than 1 ppm of fluoride seem to be significantly more likely to develop dental fluorosis in developing permanent teeth.[36]

Because fluoride supplementation is not recommended for infants younger than 6 months of age and commonly used sources of water may be fluoridated, parents may wish to consider nonfluoridated sources of water when mixing infant formula. No fluoride is necessary in exclusively breastfed infants younger than 6 months.

Toothpaste. Toothpaste (usually containing 600-1000 ppm fluoride) should not be used during infancy, an age when children are liable to swallow it. Instead, only water and a soft, age-appropriate toothbrush should be used for oral hygiene. Once children are able to expectorate, typically by 3 years of age, they should brush with a toothpaste containing fluoride, using only a pea-size dollop. Some local absorption of fluoride will occur into the slightly porous enamel of newly erupted teeth, and most children at this age will not swallow the toothpaste. However, if the child swallows only a tiny amount, it should not cause harm. After the age of 8 years, there is little to no risk for dental fluorosis because all of the tooth crowns anterior to the 12-year molar are already mineralized.

Topical fluoride treatments. Topical fluoride treatments used by dentists (sodium fluoride 2.26% or difluorosilane 0.1% fluoride) are administered to prevent caries.[37] These products can increase ingested fluoride levels, but because these treatments are applied infrequently and are professionally supervised, they are unlikely to contribute greatly to enamel fluorosis, even in young children.[38] With a growing population of patients lacking dental insurance and the difficulty of finding dentists who will take Medicaid patients, many children are going without regular topical fluoride applications.[39]

Other sources of fluoride. A minor source of fluoroacetate is produced naturally by a few plants, in sulfur vents, and by volcanic eruptions, exposures that the average American is not likely to confront. Environmentally delivered fluoride from groundwater (possibly incorporated in agricultural products) and air pollution may be responsible for exposing the growing child to uncertain, fluctuating, and possibly excess amounts of fluoride. Exposure to certain other pollutants, such as lead, with fluoride has been associated with fluorosis in rats.[40] Measurable blood lead levels occur in some children living in old houses with peeling, lead-based paint, placing these children at greater risk for fluorosis in addition to the other deleterious effects of lead.

The American Academy of Pediatric Dentistry encourages pediatric providers to assess children for caries risk (including the level of protection afforded by fluoride exposure) and provides an online tool.[41] In addition, the American Academy of Pediatrics recommends that pediatricians consider applying fluoride varnish for patients at risk for caries during well-child visits between 6 months and until the patient is able to access a dental home. An online tutorial is available.

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