How Does Fluoride Strengthens The Teeth?

how does fluoride strengthens teeth

Last Updated on August 8, 2022 by Dr Gustavo Assatourians DDS

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Before writing about how does fluoride strengthens teeth, first, we need to know what is fluoride.

What Is Fluoride?

Fluoride is a chemical substance that can be found in different forms, and its usefulness varies according to them. We speak of fluoride as an ion that we can find in our usual diet. In nature, it can be found both in the animal kingdom present in sardines, salmon, or cow liver; in vegetables, in tea, tomatoes, and potatoes. The human body has mechanisms for the metabolic regulation of fluoride that control its absorption, use, and elimination. Almost all fluoride that is retained in the body is in the bones and teeth since it cannot stand alone as an ion and must be associated with some chemical substances found in them. Fluoride that is not fixed in the bones, teeth, or soft tissues is eliminated mainly in the urine, in small amounts in the stool, and in sweat. (1)

What is Sodium Fluoride?

Sodium Fluoride is a white powder with no particular color and odor. When it is in this form it is a highly toxic chemical substance, and when exposed to heat, it generates toxic vapors. It’s on the list of dangerous substances of the right to know by OSHA, EPA, and NIOSH   along with other substances, and it must be handled by experts who take the necessary care in its use (2). Local aqueduct companies have trained people who handle sodium fluoride to be added to the water that reaches our homes in very small quantities. Supported by public health organizations since the beginning of the 20th century, a clear relationship has been established between fluoride and caries prevention. Expert analysis shows that decayed teeth have a lower fluoride content than healthy teeth,  and the occurrence of cavities was lower among children who had consumed naturally fluoridated water compared to those whose drinking water had a low concentration of fluoride. (3)

Fluoride has a double mechanism of action (4):

  1. On one hand, it transforms hydroxyapatite (mineral in teeth) in enamel into fluorapatite that is more resistant to decalcification (loss of calcium in teeth). For this reason, the topical and systemic application of fluoride is critical in the first years of life when the denture emerges.
  2. It avoids reactions of bacterial metabolism in dental plaque, reducing the formation of acids (acetic and butyric), which are essential for the decomposition of the mineral hydroxyapatite found in tooth enamel and protects it transforming it into calcium, phosphate, and water ions.

Forms of administration of fluorides

There are two main routes of administration of fluoride, systemic or topical: The systemic route includes fluoridated water, either water for public consumption or bottled water (it depends on water), some foods such as was already indicated above and, within the topical route of administration it differs (5):

  1. Toothpaste for their exclusively local action, this being the most suitable method of all due to its effectiveness and low cost.
  2. Mouthwashes: These are dilute solutions of fluoride salts to perform daily or weekly mouthwashes. It is not recommended for use in children under six years of age.
  3. Gels and varnishes: applied only by a dentist and contain a high concentration of fluoride. This type of application should focus mainly on those patients at high risk for the development of cavities paying special attention that the patient does not ingest fluoride since it could cause digestive symptoms. Therefore its use is not recommended in children under six years of age.

What happens if you overdosed on fluoride?

The benefits provided by the consumption or use of fluoride are several; however, when consumed or used in excess, it can cause other types of signs or symptoms: such as dental fluorosis (lines, spots, or streaks both white and opaque, sometimes with an unpleasant and unsightly brown color) as the most visible effect located in the dental structure and is considered the first visible sign of chronic fluoride poisoning. Symptoms, when high amounts of fluoride are ingested, are abdominal pain, nausea, vomiting, increased saliva production, diarrhea, and cardiovascular disorders among others. Long-term toxicity can lead to muscle weakness, fatigue, and weakness in the respiratory system,  and other symptoms associated with the passage of fluoride ions into the cells. (6)

The systemic use of fluoride through the topical route provides a preventive effect of dental caries without causing harmful systemic effects; however, prolonged ingestion of high concentrations of fluoride can cause other unfavorable symptoms for the patient. (6)

Therefore, the use of fluoride must always be indicated and guided by your dentist to guarantee its proper use.  This results in good dental health and ensures the safe handling of the products that contain it.

Contact us

If you have any questions about this or other topics, you can contact us on Channel Islands Family Dental and on our Facebook Page. We look forward to your visit and will give you a timely diagnosis. Our dentists in Oxnard, Santa Paula, Ventura, and Port Hueneme will be able to guide you towards the best treatment to take care of your health and return your best smile

Bibliographic References

  1., General Council of Official Associations of Pharmacists: El Fluor, Feb 24, 2017 (internet, consulted Mar 24, 2021) Available at
  2. NJHealth, New Jersey Department of Health. Right to Know: Hazardous Substances Fact Sheet. January 2010. (internet) (consulted Mar 24 2021) Available at
  3. WHO. Fluorides and Health. Monograph series 59- 1st ed- Geneva- WHO 1972.
  4. Maria B. Garcia. Fluorine, pros, and cons. Dental Gazette. September 19, 2011 (internet) (accessed March 24, 2021) Available at:
  5. General Directorate of Public Health. Valencia Department of Health. Updating of Programs. Pediatric Action in the Promotion of Children’s Oral Health. 1996.
  6. Naise L., Edith Z., Lourdes G., Effects of Prolonged Ingestion of High Concentrations of Fluorides. Our Professors Write: Magazine April 16 (internet) 2015 (consulted 24 Mar 2021) vol 54 (260): 83-94. Available at:



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