House Call: Fluoride helps balance bacteria’s wreckage

Have you ever wondered how fluoride helps strengthen teeth?

We all have naturally occurring bacteria in our mouths that form a thin coating on the teeth called plaque. It increases after you eat food with sugars and starches in them like candy, milk, bread, pasta, soda, juice, cake and crackers. These bacteria break down sugars and starches and produce acids that remove the minerals in the outer layer, the enamel, of your teeth. If the minerals are not replaced, a cavity may form, which may need to be filled to prevent further damage, stop pain and prevent infection. Fluoride helps replace those minerals. Fluoride also fights cavities by making it more difficult for the bacteria to stick to teeth.

The mineral in enamel is made of hydroxyapatite crystals. When you brush your teeth with fluoride toothpaste, a mineral called fluorapatite replaces (remineralizes) the missing hydroxyapatite. Fluoride treatments at the dentist office also help with remineralization. The fluorapatite crystals grow faster and larger and repair damage caused by acids produced by plaque. Even though the fluorapatite layer of enamel is much thinner than originally thought, it is more resistant to acids than hydroxyapatite.

As children’s teeth develop, fluoride that is ingested, such as from drinking water, gets incorporated into their teeth. In some areas, the amount of naturally occurring fluoride in drinking water is lower than the Department of Health and Human Services recommendation of 0.7 mg/L of fluoride. The fluoride levels for many areas can be looked up on a Centers for Disease Control and Prevention Web page: http://apps.nccd.cdc.gov/MWF/ Index.asp. If you are concerned about too little or too much fluoride for your child, talk to your health care provider or dentist and see what steps she recommends to increase fluoride intake or to limit it.

Since the water in Spokane has on average 0.6 mg/L of fluoride, I requested a fluoride prescription from our daughter’s physician when she was 6 months old. A fluoride prescription typically continues until the permanent teeth are all in place, usually age 12 or 13.

Just like with anything else, you can consume too much fluoride. The amount of fluoride allowed in drinking water is regulated to prevent fluorosis, a condition caused by ingesting too much fluoride. Fluorosis can cause pits in tooth enamel and over a lifetime can increase the risk of bone fractures.

When your child starts getting teeth, clean them with a small soft toothbrush and toothpaste without fluoride because she will likely swallow the toothpaste. Encourage her not to swallow it so that when you do switch her to fluoride toothpaste she will have learned not to.

The CDC recommends switching children to fluoride toothpaste at age 2. Use only a small amount of toothpaste (the size of a pea) until age 6 to continue to protect against accidentally ingesting too much fluoride. When your child transitions to brushing his own teeth, supervise brushing to make sure he does not use too much toothpaste and that he is brushing thoroughly. A timer on the toothbrush or on the counter is helpful to make sure your child brushes for the recommended time of two minutes.

Studies have shown connections between bad oral health and heart disease, diabetes, dementia, autoimmune diseases and complications of pregnancy. There is more to be learned about how dental health and these conditions are connected, but what you do right now to take care of your child’s teeth could very well keep her healthier for the rest of her life. Teaching her to take care of her teeth will also make visits to the dentist more enjoyable.