Fluoride is the negative ion of the element fluorine and is naturally found in air, soil, water, plants and some foods. It is the 13th most abundant element on earth. It has a very important role in the formation of bones and teeth. As with any substance, fluoride is very helpful and needed in small amounts but can be dangerous and toxic in large amounts.

The benefits of fluoride in dentistry were discovered in the 50’s when it was found that children in areas with higher fluoride concentration in the drinking water had significantly less caries and dental decay rates compared to those with lower concentrations.

Since the discovery of fluoride, the rate of dental decay has been reduced by more than 50% in regions where community water is fluoridated.

The Canadian Dental Association supports the appropriate use of Fluoride.

Mechanism of Action

Depending on how fluoride is introduced and applied, it has different effects and mechanisms of action:

  • Systemic – this means fluoride is ingested, absorbed into the blood stream and then affects tissues and cells from within.
  • Topical – this means fluoride is applied to teeth surfaces topically, not meant to be ingested and affects the tissues and cells from outside.

The following are the overall effect of fluoride on teeth:

  • Conversion of Hydroxyapatite Crystal of Enamel to Fluoroapatite Crystals
    • Highly Resistant to Bacterial Induced Acid Demineralization
    • When fluoride is administered systemically and specially during the development of tissues of various teeth (and bones) typically when the child is less than 15 years of age, fluoride replaces hydroapatite to fluoroapatite thereby making teeth highly resistant to demineralization.
    • After this age, fluoride is only effective when applied topically and is only able to partially replace lost hydroxyapatite to fluoroapatite.
  • Remineralization of Incipient Carious Lesions
    • By Deposition or by Reprecipitating the Mineral Ions Lost from Tooth Surface during Acid-Demineralization.
    • Topically applied fluoride is able to directly remineralize small cavities.
    • Systemic fluoride tends to get released by salivary glands and helps repair teeth.
  • Prevention of Activity of the Enzyme Glucosyl Transferase
    • Glucosyl Transferase is essential for the formation of extracellular polysaccharides
    • Hence, results in Reduction of Bacterial Adhesion to Tooth Surface
  • Limitation of Rate of Carbohydrate Metabolism by Cariogenic Bacteria
    • Hence, Reduces Formation of Acids
  • Direct Toxicity to S. mutans
    • In Higher Concentrations

In summary, fluoride is designed to do the following:

  1. Strengthen enamel.
  2. Reverse early dental decay and caries.
  3. Make teeth more resistant to dental decay, caries and erosion from acids.
  4. Reduce the ability of bacteria to stick to teeth and create acids.

How is Fluoride introduced?

Fluoride is introduced systemically through water fluoridation in over 50 countries. The level of fluoride in water is controlled very precisely and depending on the source of water, fluoride is either removed from water or added to water to obtain the appropriate level that is found to be non-toxic but beneficial to teeth.

Most ground water sources have too much fluoride and can cause fluorosis which is dark staining and pitting of teeth.

Fluoride can also be applied topically to teeth either professionally by means of a sticky varnish or through tooth pastes. Fluoride Therapy is the application of professionally available fluoride formulations to strengthen and repair teeth. Most modern tooth pastes now contain fluoride in much small amounts to help protect and repair teeth every day and replenish the fluoride in salivary glands.

PreviDent 5000 Plus High Strength Fluoride Toothpaste, 39 ml, Spearmint –  Colgate : Toothpaste | Jean Coutu
High Straight Fluoride Toothpaste
Topical Fluoride Varnish Therapy

I have heard Fluoride is harmful, why is it being used?

It is important to understand that any substance can be therapeutic or toxic depending on its dosage. The difference between sleeping pill being fatal or just letting you sleep is its dosage. Fluoride is no different.

Within the context of dentistry, topical fluoride is specially formulated to not get absorbed when ingested. However, uncontrolled application of fluoride can cause the following:

  • Stomach sickness and nausea
  • Dental Fluorosis
Dental fluorosis causes, prevention, symptoms & dental fluorosis treatment
Dental Fluorosis

Some people and organizations claim that fluoride can cause bone cancer, low IQ scores and mental diseases. There are no studies to prove any of these claims and in fact there are studies to prove these claims are entirely false.

What should I do to maximize the effects of Fluoride?

Depending on the brand and quality of varnish used, you may need to completely avoid eating and/or drinking.

With the varnish that we use at Stouffville Smiles Dentistry, we (and the manufacturer) recommend that you avoid eating hot and/or crunchy food for a minimum of 2 hours. This varnish is specially formulated to stick to teeth and will not come off when you’re eating softer food and/or drinking room temperature of cold liquids.

For tooth pastes, we always recommend first of all not rinsing your mouth after brushing and just spitting the excess foam out and to not eat and/or drink for a minimum of 30 minutes.

Fluoride is best applied after cleaning and scaling of the teeth to maximize its topical effects.