How does Fluoride help prevent tooth decay?
Fluoride is a mineral formed from the element fluorine that is found naturally in the environment and also incorporated into products for our teeth. Fluoride helps with both the formation and protection of our teeth. Tooth enamel is made up of calcium hydroxyapatite which provides a hard outer surface to protect the inner layers of our teeth. When fluoride is present during tooth formation or remineralization, it also incorporates itself into the tooth structure forming calcium fluorapatite. This addition of fluoride makes the tooth structure even stronger because fluoride is able to withstand more acidic environments.
Dental caries, known by many as 'cavities', occurs when the bacteria in your mouth metabolize the sugars in your diet. As the sugar is metabolized, acid is released which demineralizes tooth structure and over time this causes a cavity. The mouth has to reach a lower pH for the fluoride in fluorapatite to begin to demineralize than that of hydroxyapatite, which is why tooth structure that has fluoride is more protective against dental caries.
Topical Fluoride
Topical fluoride is fluoride that is applied directly to the teeth. One route of administration is over the counter products such as fluoride containing toothpastes or mouth rinses. Topical fluoride is also applied professionally at dental appointments in the form of gels, foams, or varnishes. This method of fluoride application helps by promoting remineralization of tooth structure.
It is recommended to brush your teeth with fluoridated toothpaste twice daily for two minutes each time. This provides teeth with an appropriate amount of fluoride to help strengthen and protect them. For young children, as teeth begin to come in parents can begin brushing gently with a very small amount of toothpaste, about the size of a rice grain. This will help children get used to the idea of brushing along with applying a small and safe amount of fluoride to help protect their primary teeth. Around the age of three, children can start learning to brush their own teeth. This should still be done with direct supervision to ensure that they are using the correct amount of toothpaste- about the size of a pea a this point. It's also important to make sure they are using the correct technique, brushing for long enough, and not swallowing their toothpaste. Once children are older and you are sure they have the technique of tooth brushing accomplished without direct supervision it is still important to check in that they are following guidelines.
At dental hygiene visits most children will receive professional topical fluoride application through a gel, foam, or varnish application. This is a higher concentration of fluoride than what is found in over the counter products which is why it only needs to be used a couple of times a year under professional guidance. This application will give a fluoride boost to teeth as they are developing and changing from primary to permanent dentition.
In patients that are at a higher risk of dental caries, often times a dentist will recommend additional fluoride products. Most often we see this in the form of a prescription toothpaste, but sometimes could be a prescription based mouth rinse or gel. Over the counter fluoride toothpaste typically contains a fluoride concentration of about 1,000 to 1,500ppm, whereas prescription fluoride toothpaste contains a fluoride concentration of about 5,000ppm. If you are determined to have higher risk of dental decay then your teeth need to be protected from the increased demineralization process of tooth enamel. Providing your teeth with a higher concentration of fluoride will help to encourage teeth to re-mineralize and be more resilient to acidic breakdown.
It is important to note that if you are at a higher risk of dental caries, fluoride alone is not the only solution. It is crucial to also keep up with proper oral hygiene to remove plaque and debris from the teeth along with limiting sugar and acid exposure to your teeth with food and beverages.
Systemic Fluoride
The other way fluoride helps teeth is through systemic fluoride application. Systemic fluoride is is ingested and incorporates into your body just like many other vitamins and minerals we need for our overall health. Systemic fluoride is especially important for children because it helps to strengthen teeth as they develop. Systemic fluoride also incorporates itself into the make up of saliva, which is helpful because this helps provide fluoride ions to the teeth topically as well. When your mouth is exposed to an acidic change your saliva helps to neutralize the acid in your mouth and when fluoride ions are present in saliva they will incorporate into the re-mineralization phase of teeth after an acidic exposure.
The most common way for fluoride to be obtained systemically is through community water sources. The US Centers for Disease Control and Prevention (CDC) declared that community water fluoridation is one of the 10 great public health achievements of the 20th century due to seeing a drastic decline in dental caries since community water fluoridation was initiated about 70 years ago. The American Dental Association reports that studies show water fluoridation reduces dental caries by 20-40%, making it the most effective public health measure in prevention of dental decay.
You can check the fluoride level of your community water supply through your local, county, or state health department to make sure it is to appropriate level. Current recommendation is for water sources to contain 0.7 parts fluoride per million parts water.
If you have a private well, consume only bottled water, or have certain types of home water treatment systems then you may be losing the benefits that come from systemic fluoride that is incorporated into community water sources. If this is the case then it is recommended that your personal water source be tested for fluoride levels from a certified lab. This is particularly important to be aware of for children as their teeth are developing. Depending on fluoride concentration, dental caries risk, and child age different concentrations of fluoride supplements can be given to make up for your water supply not being to optimal level. If the fluoride levels are low then it’s important to discuss this with your child’s physician and dentist.
Safety of Fluoride
Overall, fluoride is very safe and its benefits to dental health are important. As with any vitamin, mineral, or even water itself, using it in massive quantities can create toxic effects. However if monitored and used in recommended amounts then this is not something to worry about.
Dental fluorosis is something that can happen during a tooth’s developmental stages if too much fluoride is ingested over a long period of time. This is only a concern while teeth are forming in children. Once teeth are developed and fully erupted into the mouth they cannot develop fluorosis. The ADA notes that the mechanism of tooth fluorosis is not fully understood but is thought to be from fluoride altering protein metabolism during tooth development.
Fluorosis affects the appearance of teeth. This can be mild white spots or striations on the teeth or more progressed with stained pits within the enamel. Fluorosis does not affect the overall health of the tooth and is actually thought to be protective against dental caries. An important way to prevent this is to supervise children with fluoride products. Keep toothpastes and other dental products out of reach so they are only using them with parental guidance. When they are using fluoride products make sure it is the correct amount and that they are not ingesting excessive quantities.
The use of fluoride has been an immense help in protecting teeth and cutting back on the incidence of dental caries. If you have any questions about the amount and sources of dental fluoride you are using then have a conversation with your dentist about what is best for you and your family.
Sources for reference:
ADA: Fluoride: Topical and Systemic Supplements
https://www.ada.org/resources/research/science-and-research-institute/oral-health-topics/fluoride-topical-and-systemic-supplements
ADA: How Fluoride Helps Prevent Tooth Decay
https://www.mouthhealthy.org/all-topics-a-z/fluoride
ADA: Healthy Habits
https://www.mouthhealthy.org/life-stages/babies-and-kids/healthy-habits-babies-and-kids
ADA: Fluoridation FAQs
https://www.ada.org/resources/community-initiatives/fluoride-in-water/fluoridation-faqs
CDC: Community Water Fluoridation
https://www.cdc.gov/fluoridation/faqs/about-fluoride.html