Fluoride… either you believe in it or you don’t. With vast information available on the internet, many patients come in our Center with misguided information about fluoride. The World Health Organization urges its member states to ensure that people are exposed to the appropriate amount of fluoride; and that universal access to fluoride is part of the basic right to human health (WHO, 2007) . But on the other end of the spectrum, there are fluoride activists who claim that fluoride is toxic to the body, is a carcinogen and should be avoided at all costs. While fluoride is not considered an essential nutrient, it does play a key role in tooth decay. And we all know that tooth decay is not be belittled, as the teeth are critical for nutrition. We all need to eat, right? Therefore, while teeth play a vital role in chewing, fluoride plays an important role to keep our teeth healthy to nurture our overall health.
How dental caries or tooth decay happens
Our teeth are our hardest bones, with enamel (the outer covering of the tooth) being the most highly mineralized tissue in the human body. And so it takes a LOT for the tooth to dissolve. In the presence of an acid-producing bacteria, when we eat a fermentable carbohydrate (any food or drink with sugar and starch), acid is produced, challenging the threshold of our enamel to demineralize. Demineralization means the enamel loses minerals, therefore making the tooth weaker. The good news is we can reverse demineralization by decreasing not only the quantity of our sugary and starchy intake but also its frequency, brushing our teeth with fluoride toothpaste twice a day and boosting the production of our saliva. The demineralization and remineralization factors should constantly be in balance. If the scale is tipped and demineralization factors outweigh the remineralization factors constantly, then tooth decay is inevitable.
What is fluoride and what it means to the teeth
Fluoride is absorbed into the teeth by way of saliva. It was discovered that fluoride strengthens the teeth when the hydroxyl ions are replaced by fluoride, forming hydroxyapatite. When the teeth are stronger this way, the teeth become more resistant to acid and enamel demineralization. And so, this means that when we drink that frappuccino or eat those gummies, a fluoride-strengthened tooth will be less soluble to acid and more resistant to demineralization. Fluoride inhibits glycolysis (the fermentation of sugars into acid); inhibits plaque (biofilm where bacteria live) colonization and therefore has a direct antibacterial effect.
Fluoride occurs naturally in certain parts of the world — like in land, water and air; therefore we ingest certain food like fish, leaves and water without our knowledge. Although in the Philippines, the natural-occurring fluoride may not be as abundant, as it is in other countries, like the United States.
Fluoride can either be ingested or applied to the teeth. With its great potential, it has been added to drinking water, vitamins, milk and salt to facilitate its absorption in the community; and it has also been added to toothpastes, mouthrinses, gels and varnishes. The 2016 publication by the WHO presented the current evidence of the different fluoride vehicles and strategies. WHO also stated that community water fluoridation is one of the greatest public health achievements of the 20th century. Drinking fluoridated water attributes caries reduction between 30%-59% on primary and permanent teeth, respectively. (Rugg-Dunn and Do, 2012).
Recent evidence states that fluoride’s method of action is predominantly topical and when the teeth have erupted. Fluoride should be given in low-dose higher- frequency approaches (Adair, 2006). This rationalizes the use of fluoride toothpastes to maintain a low level of fluoride in the mouth. The effectiveness of fluoride toothpastes to prevent tooth decay has been documented extensively in several systematic reviews (Marinho, et al., 2003; Twetman, 2009, Wright et al., 2014). To achieve caries-preventive effects, a systematic review recommends the use of at least 1,000 ppm of fluoride (Walsh et al., 2010). For those with high caries risk, “high fluoride” toothpastes containing more than 1,500 ppm F (2,000 - 5,000 ppm F) may be prescribed to manage the risk of these patients. Twice a day of of toothbrushing is also more effective than brushing once a day (Marinho, 2003). Fluoride mouthrinses may also be prescribed for our older children who are able to spit and are assessed to be of high caries risk. Evidence supports the anti-cavity benefits of mouthrinses. With different formulations available in the market, it is best that you ask your dentist about this.
The professional application of fluoride using fluoride varnish and the fluoride gels, is done by the dentist, after doing a proper caries risk assessment of the patient. Both have a very high fluoride content and show evidence in preventing tooth decay. High levels of fluoride produce a temporary layer of calcium fluoride-like material on the enamel surface; and during an acid challenge (eating a fermentable carbohdyrate), fluoride is released and becomes available to remineralise enamel.
Too much fluoride
What happens when a child takes in too much fluoride? Since fluoride is deposited in bone, then chronic ingestion can lead to chronic toxicity which can manifest on the teeth and other bones. For the teeth, when excessive fluoride has been taken by a child during enamel development (below 8 years old), this is called dental fluorosis where it manifests as mild as white specks to pitting and severe brown staining. For longer periods of chronic ingestion, it can deposit on bones and cause deformity, which we call skeletal fluorosis. Some populations, mainly from India and China are at particular risk because of the abundance of fluoride in land, water and air. But if a child ingests fluoride in large amounts, then acute toxicity can occur with symptoms of nausea, vomiting, abdominal pain, headaches, hypotension and in rare cases, cardiac arrythmia. However, it should be noted that acute toxicity happens very rarely, as it would take a 2 year old to ingest 3/4 of a 60 g 1,000 ppm-F-toothpaste for the child to reach the probable toxic dose of 5 mg/kg body weight; or 3 tubes of a 400-ppm-F-toothpaste. When this happens, please bring the child to the nearest Emergency Room for management.
In the Philippines, fluoride naturally occurs in the waters of Cavite; and some tea leaves. We would get dental fluorosis cases from the children residing in Cavite, or due to too much fluoride from multi-vitamins. But currently, we do get less dental fluorosis from the Cavite children, as Filipinos are now drinking more bottled water. But when mild or more severe fluorosis is found to a significant extent in a community, the WHO recommends to take steps to reduce fluoride ingestion by children with developing teeth (WHO, 2016).
Recommendations
Just like with any vitamins, fluoride should be used appropriately. To limit the risk of fluorosis, the Pediatric Dentistry Center Philippines recommends:
- Brush teeth twice daily with 1,000 ppm - 1,450 ppm of fluoride toothpaste. According to the American Academy of Pediatric Dentistry (2023), brush with the right amount according to the age of the child:
- 0-3 years old : smear amount of toothpaste
- 3-6 years old : pea size of toothpaste
- If your child is still unable to spit by age 6, then please stick to the pea size amount of toothpaste. Older children who are able to spit may use a full-length amount of toothpaste on the toothbrush head.
- Be cautious with candy-flavored toothpaste for young children to avoid large ingestions of toothpastes. Some children think it’s candy! Likewise, we also advise that toothpastes should be out of reach from small children.
- To maximize fluoride absorption on the teeth, teach the children to spit and DO NOT rinse. Rinsing with water after toothbrushing washes out the fluoride from the mouth, minimizing the fluoride uptake on the teeth. (O’Mullane, 2013).
- Toothbrushing is ideally done as the last activity before sleeping; and another time during the day (e.g. before going to school).
- Supervise toothbrushing until the child is 8 years old; or until when the child has mastered the swallowing reflex.
- Bring your child to a dentist by his/her first birthday. Your child’s dentist will be able to guide you on how to best take care of your child’s oral health. Every child’s dental needs are different and each child’s history and habits will be assessed for caries risk. Your dentist will then be able to guide you on what fluoride vehicle, its frequency and other specific instructions best for your child.
- Fluoride varnish is to be applied at least twice a year, depending on the child’s caries risk.
Other recommendations to keep your child’s teeth healthy:
- Decrease snacking frequency to decrease the acid attack on our teeth. We recommend to limit snacking to less than 2 times in a day.
- Teach your children to drink water, and more water! Children nowadays are so much into drinking juices, milk tea, frappuccinos and other sugary drinks. Sugar-sweetened beverages has so much sugar in one cup that it exceeds the recommended intake of sugar in a day.
These are the recommendations of the Pediatric Dentistry Center Philippines, as aligned by the current evidence today. However, we do get patients who are non-believers of fluoride. We respect your beliefs and we respect that you as parents are the best advocates for your children. For children who do not use fluoride, then that means we will have to utilize other protective factors to keep the scale balanced for your child to have healthy teeth. Please continue to have regular visits with your dentists.