How does fluoride make your teeth stronger?  

How does fluoride make your teeth stronger

Fluoride has been used in toothpaste, mouthwashes, and water supplies for decades to make teeth stronger. However, people often wonder how does fluoride makes your teeth stronger. In this article, I will walk you through the mechanism of how fluoride incorporates into the teeth. Also, what is the safe dosage of fluoride that strengthens teeth without causing any harm to the teeth and bones?

Let’s get started: 

What is fluoride?

Fluoride is a natural occuring element found in rocks and soil. The water from rivers, seas, wells, and lakes, when it passes over the rocks, takes some fluoride. These water resources are the natural sources of fluoride, however, they contain higher fluoride levels than required for the healthy teeth.

These effects of fluoride were recognized in the early 20th century. Later on, several studies were carried out to establish the optimal levels of fluoride for oral health. The first trial of water fluoridation was conducted in the US and Canada in 1940 that showed a significant decrease in tooth decay. 

Water fluoridation is a process where an optimal fluoride level is added to the water supplies to prevent cavities and decrease the global burden on the healthcare system.

Ministry of health, NSW, Autralia.

A decline in cavities after the fluoride was added to Australian drinking water

Tooth decay is a diet-related global disease and is a massive burden on the healthcare system. 

There was a 26-44% decline in tooth decay in all age groups in New south wales (NSW), Australia with the introduction of water fluoridation. For every dollar spent on water fluoridation, 7 to 8 dollars are saved on the treatment cost in NSW, Australia. 

Water fluoridation: dental and other human health outcomes, Australian Government, NHRMC.

According to a current estimate, 350 million people drink fluoridated water worldwide. 

Composition of tooth enamel

Enamel is the outer tough layer of the teeth that protects the inner layers of the teeth. 

It covers the crown portion of the tooth, the part you see in the mouth. The root portion of the tooth is hidden in the gums and bone and is covered by cementum.

The enamel is a crystalline structure composed of various minerals predominantly calcium and phosphate minerals (96%). The calcium phosphate crystals are hexagonal in shape resembling a prism, known as hydroxyappatite crystals. 

Minor quantities of fluoride, lead, strontium, and magnesium are also present in the enamel. 

Enamel doesn’t contain any living cells and can’t repair and regenerate itself once it’s lost. Therefore, it requires special care to protect the inner and more sensitive layers of the teeth.

Fluoride strengthens enamel and makes it more resistant to cavities. However, excess fluoride intake can turn your teeth yellow or brown, especially if taken at a younger age when teeth are developing.  

How does fluoride make your teeth stronger?

Fluoride makes teeth stronger by making teeth more resistant to acid attack. It is absorbed into saliva through fluoridated toothpaste and mouthwash and secreted from the blood into the saliva from drinking (fluoridated) water and ingested fortified foods.

Fluoride (from saliva) remineralizes the demineralized, damaged enamel. Simple sugars (refined foods) in the diet are damaging to enamel because plaque bacteria readily metabolize them to organic acids. This acid pulls calcium and phosphate ions out of the enamel. The saliva remineralizes the enamel by providing calcium, fluoride and bicarbonate ions and restores its strength within 20-30 mins.

Fluoride incorporates into the enamel crystals and forms fluorapatite crystals. These crystals are more resistant to acid attack and erosion and thus make your teeth stronger. 

Can too much fluoride make your teeth yellow or brown?

Yes, fluoride can make teeth yellow if you or your child is exposed to high fluoride levels during tooth formation. The yellow and brown stains on the teeth due to excess fluoride exposure during teeth development is known as dental fluorosis. 

The risk of dental fluorosis is highest between the age of 1 to 4 years when the crown portion of the permanent teeth is developing. However, excess fluoride exposure between the age of 0-12 years can have damaging effects your child’s developing teeth and bones.

Excess fluoride from drinking water and other sources incorporates into the teeth during their development. It disrupts the enamel formation and forms weak, fragile and mineral deficient teeth.

How does excess fluoride disrupts enamel formation?

High fluoride levels in diet interfere with the mineralization of enamel during its development. In the early stage of enamel formation, protein scaffolding is laid down by the enamel-forming cells at the site of future enamel. 

Later on, as the enamel matures and mineralization begins, the protein is removed and replaced by calcium and phosphate ions. Fluoride decreases the protein breakdown and delays its removal from the enamel, resulting in soft and porous enamel. 

The resultant weak, protein rich, and mineral deficient enamel breaks away and stains to brown color.

What does too much fluoride on teeth look like?

The appearance of dental fluorosis banks on the amount of fluoride exposure during teeth development. The higher levels are linked to severe damage to enamel and vice versa.

What are the Safe levels of fluoride in water?

The optimal level of fluoride beneficial for teeth is 0.7 mg/l of fluoride. According to WHO, the permissible limit of fluoride in drinking water is 1.5 mg/l.

The US environmental protection agency (USEPA) recommends 0.06 mg fluoride/kg/day as estimated daily exposure to fluoride without the risk of harmful effects on teeth. You can calculate you and your’s family’s safety dosage of fluoride by using the USEPA value.

Furthermore, in a study, Dean and Elove saw marked reduction in dental cavities with no adverse effects at 1ppm (parts per million) fluoride in drinking water. The water fluoridation in most of the US states is 0.07 ppm, which is safe.  

Fluoride Toxicity in children

Children are at high risk of fluoride toxicity and should not be given fluoridated toothpaste for up to 6 years. The children swallow more fluoride from toothpaste than from all combined sources. Ingestion of fluoride may be toxic to the child and cause nausea, vomiting, or stomach ache.

There is a wide range of kids’ toothpaste available in the stores. Kid’s toothpaste is low in fluoride and is safe for children.  

It is recommended to use plain water to clean the child’s teeth between 0 to 18 months and no toothpaste. A pea-sized kid’s toothpaste smeared across the toothbrush is beneficial for children between the age of 18 months to 5 years. Adult supervision is necessary while they brush their teeth.  

Safe sources of fluoride that make teeth stronger

If you live in an area where fluorosis is not an issue, the following are good sources of fluoride but ensure not to exceed the benchmark for fluoride toxicity. 

  • Fluoride toothpaste and mouthwash for children above six years. 
  • If you live in an area where there is no water fluoridation and your child is getting cavities despite keeping good hygiene and diet management, talk to your dentist about fluoride varnishes. Fluoride varnishes prevent cavities by filling pits and fissures on the back teeth (molars). 
  • Add calcium and fluoride-rich foods to your diet, such as cow’s milk. 
  • Fluoride supplements are not recommended unless prescribed by your GP or dentist as they contain a high dosage of fluoride.

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