Fluoride, like so many things these days, is a controversial topic, with most people either strongly for or against it. On one side, people claim that the research from many decades supports the use of fluoride. On the other side, there are claims that it is a toxin and there are other natural substances that work better. So, what is the truth? What are the benefits and disadvantages of fluoride and how much is safe?
First, fluoride is a natural substance found in the soil, water and many foods. It is found when the element fluorine combines with other elements to create fluoride ions. Water passes over rocks and soil containing fluoride which dissolves into the water. So, all water, even ocean water, contains some amount of fluoride. In addition to consuming it in water, you get it in seafood and in most fruits and vegetables. Fish, potatoes, beans, greens, citrus, avocados, sunflower seeds, apple juice and many other foods are all great sources of fluoride.
If fluoride is a natural substance found in our food and water that is good for us, why do people make such a big deal of it?
The answer is that, like many natural substances, too much of a good thing can be harmful. High concentrations can cause dental fluorosis, which is when white specks or streaks appear in the tooth enamel, but they do not affect the tooth’s health. Excess consumption of fluoride can cause skeletal fluorosis which can eventually cause pain and damage to bones and joints. Excessive amounts can impact calcium levels, harm the parathyroid gland and act as a neurotoxin. However, all these problems are caused by consuming far greater amounts of fluoride than is recommended.
How much fluoride is safe to consume?
The optimal amount of fluoride for the average person is .05 mg per kg of body weight per day which converts to approximately .023 mg per pound per day. This means that the recommendation for a child who weighs 33 pounds (15 kg) is 1.65 mg per day, an 88-pound (40kg) child should consume 2 mg of fluoride per day, and a 132-pound (60 kg) adult should get 3 mg each day.
If we naturally consume fluoride in our food and water, why do we need it in toothpaste?
Many things cause your tooth enamel to erode, and once it is gone your body does not regenerate it. Once this happens, you can remineralize your teeth, which happens when you add minerals back to the enamel. One of the best minerals for remineralization is fluoride, which also helps prevent the erosion in the first place. Unfortunately, many of us do not consume enough fluoride to meet recommended quantities, and topical fluoride is the most effective way to protect your tooth enamel.
It is true that for many years scientists were not completely sure how fluoride worked to keep your enamel from eroding. They could only prove that it did and theorize how it may work. However, chemists have discovered that fluoride ions stick firmly to several calcium ions near the surface of the tooth. This helps bind the calcium ions together, which slows the speed that the enamel is worn away.1 This binding also makes it difficult for decay-causing bacteria to stick to teeth, making it simpler for saliva and tooth brushing to wash away the harmful bacteria.
Scientists believe fluoride also works to prevent cavities by limiting the amount of acid produced by bacteria in plaque and minimizing development of harmful bacteria on the teeth. Additionally, it increases the rate of growth and size of enamel structures which helps teeth remineralize after they have been decalcified by acids, also reversing early cavity formation. Remineralization creates stronger tooth enamel, which makes it more resistant to decay.
However, for these benefits, fluoride must be applied frequently in low doses. When you brush your teeth, fluoride from your toothpaste is deposited onto your teeth. Then you eat meals and snacks, and each time you chew the fluoride is disturbed and detached from the enamel on your teeth. While saliva works to protect your teeth, it also rinses off the protective fluoride, allowing harmful bacteria to get to work on wearing down your tooth enamel. This is the reason brushing twice a day with fluoride toothpaste is recommended, so you can continually renew the fluoride on your teeth.
Why then do people who use fluoride toothpaste twice a day still get cavities? This is largely due to a high sugar diet. The balance of helpful and harmful bacteria in your mouth is delicate. The harmful bacteria feed on sugars and create acids which wear down your enamel. When you eat a diet high in sugars, the harmful bacteria increase the amount of acids they produce, overwhelming the enamel strengthening benefits of fluoride and eventually causing cavities.
How much fluoride will my child get from toothpaste?
The American Dental Association recommends that children under 3 use a rice grain sized amount of toothpaste, and children 3 - 6 years old use a pea sized amount. Even if a child swallows the entire amount, this keeps levels far below recommended amounts. “For example, if a child weighing 15 kg brushed twice per day, using a rice-sized smear of toothpaste (approximately 0.1 gram of toothpaste or 0.1 milligram of fluoride), swallowed the entire smear he or she would ingest 0.2 mg of fluoride, resulting in a dose of 0.013 mg/kg. Under those same conditions, the Association estimates, a child using a pea-sized amount (approximately 0.25 g toothpaste or 0.25 mg fluoride) would ingest 0.5 mg fluoride, resulting in a dose of 0.033 mg/kg.”2 As you can see, 0.2 mg is much less than the recommended 1.65 mg for a 33 pound/15 kg child, and 0.5 mg is only a quarter of the recommended 2 mg for an 88 pound/40 kg child.
It is important to brush your child’s teeth until they are 6 or 7 and supervise while teaching them how to brush for a few years after that, so they are only exposed to safe levels of fluoride. It is important to train your child how to use the proper amount of toothpaste, and to spit it out instead of swallowing it. Younger children are more likely to get too much fluoride from using and swallowing too much toothpaste, and even caregivers have been found to commonly use double the recommended amounts of toothpaste. While toothpaste and the fluoride in it are vitally important to the health of your teeth, it is equally important to use them correctly!
Where else do we get fluoride?
Since children’s teeth are still forming, they benefit even more from the strengthening properties of fluoride. Dentists apply a fluoride varnish to children’s teeth at their regular checkups to boost the health and strength of their teeth’s natural protective layer of enamel. Fluoride can also be added to drinking water. Each child’s needs are different, so your dentist can help you determine if your child would benefit from this.
So, should your family use fluoride? Absolutely! Regular use of toothpaste with fluoride in recommended doses is important to maintaining oral health. Strong and healthy teeth are made stronger by fluoride, and cavities in early stages can be combatted with regular exposure to fluoride. While excessive use of fluoride may cause health problems, training your child in good oral hygiene habits and how to use proper amounts of toothpaste will prevent those issues. However, please don’t forget that fluoride can only provide some protection. Most of your oral health is up to you and requires a healthy diet low in sugar, regular visits to your dentist, and consistent brushing and flossing.
At Jungle Roots Children’s Dentistry & Orthodontics, we strive to provide the highest comprehensive pediatric and orthodontic dental care in a unique, fun-filled environment staffed by a team of caring, energetic professionals. We believe the establishment of a “dental home” at an early age is the key to a lifetime of positive visits to the dentist.
Nora H. de Leeuw†,‡
The Journal of Physical Chemistry B 2004 108 (6), 1809-1811