Preventing caries: fluoride, sealants and diet
- Topic
Fluoride toothpaste twice a day, less frequent sugar, varnish and molar sealants prevent most caries. Too much fluoride in childhood causes fluorosis.
What it is
Fluoride prevents caries mainly by acting on the tooth surface: it slows demineralisation, speeds remineralisation and is incorporated as fluorapatite, and it inhibits bacterial acid production. Community measures (fluoridated water or, in Colombia, fluoridated salt) and personal measures (fluoride toothpaste) reach most people; professionally applied fluoride varnish adds protection for children and high-risk adults. Pit-and-fissure sealants are thin plastic coatings on the grooves of molars that block plaque and are most useful soon after the permanent molars erupt. Reducing the frequency of sugar is the other pillar. Excess fluoride swallowed while teeth form causes dental fluorosis.
Key facts
- Brush twice a day with fluoride toothpaste; spit, do not rinse with water afterwards.
- Children: a smear (rice-grain size) under three years; a pea-sized amount from three to six years; brushing supervised by an adult.
- Fluoride varnish: applied by trained staff to children and high-risk patients at regular intervals.
- Sealants on permanent molars soon after eruption greatly reduce occlusal caries.
- Fluorosis risk rises when young children swallow toothpaste and other sources of fluoride add up.
In clinical practice
- Children who eat toothpaste or use adult amounts are at risk of fluorosis; supervision matters.
- Xylitol gum and chlorhexidine varnish are adjuncts, not substitutes for fluoride.
- Fluoride supplements (drops or tablets) are not used where salt or water is already fluoridated.
Next step / Initial management
- At every child visit: check brushing, advise on toothpaste amount and sugar, and apply fluoride varnish where the routine pathway allows.
- Refer children for sealants when the permanent molars erupt, and anyone with active caries to the dentist.
- Mottled or streaked enamel: review all fluoride sources before advising more.
Test yourself
Think of the answer, then tap the question to see it.
How much fluoride toothpaste should a child under three use?
A smear the size of a grain of rice, with an adult brushing.
Why is rinsing with water after brushing discouraged?
Because it washes away the fluoride left on the teeth.
What do pit-and-fissure sealants prevent?
Caries in the grooves of the biting surfaces of molars.
Connections
In Pharmacology2
Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.
Sources: The Role of Fluoride on Caries Prevention (StatPearls Publishing (NCBI Bookshelf), 2023); Fluoride (National Institute of Dental and Craniofacial Research (NIDCR, NIH), 2024); Dental Sealants (National Institute of Dental and Craniofacial Research (NIDCR, NIH), 2024); About Fluoride | Oral Health (Centers for Disease Control and Prevention, 2026); Dental Fluorosis (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.