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Fluoride 101

Babies, Toddlers and Preschool Children Need Fluoride Toothpaste and Fluoride Varnish to Prevent Tooth Decay

Fluoride is a proven way to strengthen teeth and prevent tooth decay. Fluoride occurs naturally in water, rocks and soil. Fluoride protects teeth in two ways: topically and systemically.


Topical fluoride strengthens teeth already present in the mouth by becoming incorporated into the surface of teeth. This makes teeth more resistant to tooth decay. Topical fluoride can also reverse early tooth decay (white spots along the gum line and between teeth or in molars) but only before a cavity (hole) is formed.

Primary Sources of Topical Fluoride:

  • Toothpaste
  • Mouth rinses
  • Professionally-applied fluoride varnish
  • Fluoride gels and foams
  • The topical effects of fluoridated water and dietary fluoride supplements.


Fluoride is deposited in the developing teeth (under the gums) and erupted teeth when ingested regularly. Systemic fluoride can also give a topical protection through saliva bathing. This helps teeth that have already emerged into the mouth be more resistant to tooth decay.

Primary Sources of Systemic Fluoride:

  • Fluoridated water
  • Dietary fluoride supplements (tablets, drops and vitamins)

Tooth Decay:

Tooth decay progresses when oral bacteria (mainly strep mutans) colonize and create a dental plaque on the teeth. When the bacteria are exposed to carbohydrates, acid is produced. The acid can destroy teeth through the loss of tooth minerals. Fluoride helps prevent tooth decay by:

  • Strengthening teeth
  • Repairing early tooth decay

Preventing Tooth Decay:

For young children, getting small amounts of fluoride daily at home is important to protect teeth. Sources: Tooth paste and either fluoridated water or dietary fluoride supplements.

Additionally, getting professionally applied fluoride periodically will strengthen young teeth and reverse early tooth decay. Children who get at least four applications of fluoride varnish before age four years have less tooth decay. Children who get fluoride varnish at earlier ages benefit even more.

Here are some resources to learn more about fluoride:

Well Water Testing Form

Maine Communities with Fluoridated Water

USPSTF: Primary Medical Care & Fluoride Varnish

PEDIATRICS: Fluoride Use in Caries Prevention in the Primary Care Setting – (Pediatrics, June 9, 2014)

JADA: Toothpaste Use in Children

ADA: Fluoridation Facts – a useful guide

CDC: Fluoridation