Fluoride

What is Fluoride?

Fluoride is a naturally occurring element that strengthens teeth. This can help to prevent tooth decay. Experts say the best way to prevent tooth decay is to use several sources of fluoride.

Fluoride is found naturally in water sources in small amounts. Some foods, such as meat, fish, eggs and tea, contain fluoride. It also is added to water in some areas. Many toothpastes, rinses and professional treatments contain fluoride. Prescription fluoride tablets are available for children who do not get fluoride in their water.

What is Fluoride used for?

Enamel is the outer layer of the crown of a tooth (the visible part). It is made of closely packed mineral crystals. Every day, the enamel loses and gains minerals. The loss of minerals is called demineralization. Gaining new minerals is called remineralization. These two processes balance each other.

Demineralization begins with the type of bacteria that cause plaque on your teeth. These bacteria feed on sugar in your mouth and produce acids. The acids dissolve the crystals in your teeth. Remineralization builds the enamel back up. In this process, minerals such as fluoride, calcium and phosphate are deposited inside the enamel. Too much loss of minerals without enough repair of the enamel leads to tooth decay.

Fluoride strengthens teeth by helping to speed remineralization. This strengthens enamel. Fluoride also helps to stop bacteria from making acids.

Fluoride can strengthen teeth in two ways — from the outside or the inside.

Teeth absorb fluoride on the outside in several ways:

  • When you get a fluoride treatment at the dental office
  • When you brush with fluoride toothpaste or use a fluoride rinse
  • When fluoridated water washes over your teeth as you drink

Fluorides that are absorbed by making contact with the outside of the tooth are called topical fluorides. Fluoride also strengthens teeth from within. Swallowed fluoride enters the bloodstream and becomes part of the permanent teeth as they develop. This is called systemic fluoride. The teeth become stronger, so it is harder for acids to destroy the enamel.

Children swallow systemic fluoride in any of the following ways:

  • Fluoridated water and drinks made from it
  • Prescription fluoride supplements
  • Small amounts of fluoride in food

Dental office fluoride treatments commonly are given to children as their teeth are developing. A child who has a history of cavities or is at high risk of decay should use additional fluoride. This promotes remineralization of the teeth. Many children get fluoride treatments every six months. The treatments provide extra protection against cavities, even if children already drink fluoridated water.

Fluoride mouth rinses also can help children with a history of cavities or a high risk of decay. These rinses are recommended for children over age 6. You can find them in the mouthwash section of most stores. Prescription fluoride rinses and gels that provide a higher level of fluoride also are available.

Fluoride treatments help to prevent decay in both children and adults. Anyone who is at risk of dental decay is a good candidate for topical fluoride treatments. This fluoride is applied directly to the teeth.

Factors that increase the risk of tooth decay include:

  • A history of cavities
  • Infrequent dental visits
  • Poor brushing habits
  • Poor diet habits, especially frequent snacking

Many common medicines can cause the mouth to be dry. Examples include antihistamines and medicines for high blood pressure, anxiety and depression. Without enough saliva, tooth decay gets worse quickly.

How can I prepare for the fluoride treatment?

Before you have an in-office fluoride treatment, your teeth should be clean. Your dentist may need to polish away stains. If you use fluoride rinses or gels at home, first brush your teeth thoroughly and floss them. It’s a good idea to use fluoride products at night before bedtime. When you are sleeping, they are less likely to be washed or rinsed away.

What should I expect from a fluoride treatment?

Before you have an in-office fluoride treatment, your teeth should be clean. Your dentist may need to polish away stains. If you use fluoride rinses or gels at home, first brush your teeth thoroughly and floss them. It’s a good idea to use fluoride products at night before bedtime. When you are sleeping, they are less likely to be washed or rinsed away.

How is the fluoride treatment done?

The fluoride treatments you receive in a dental office have more fluoride than over-the-counter fluoride mouthwash or toothpaste. They are used for both children and adults. Dental-office treatments also are different chemically and stay on the teeth longer.

There are two common types of professionally applied fluorides. Acidulated phosphate fluoride (APF) is acidic; neutral sodium fluoride is not. Neutral sodium fluoride usually is used for people who have dry mouth (xerostomia) or who have tooth-colored fillings, crowns or bridges. An acidic fluoride may irritate a mouth that is dry. It also can create small pits in tooth-colored plastic composite fillings.

Fluoride is applied as a gel, foam or varnish during a dental appointment. The teeth are dried so the fluoride doesn’t become diluted. Fluoride gel or foam can be applied by using a tray that looks like a mouth guard for one to four minutes. Fluoride varnish can be painted directly on parts of the teeth that are most likely to get a cavity, to strengthen them. This is an advantage of varnish over gel or foam. Varnish also contains a very strong concentration of fluoride. Topical fluoride comes in a variety of flavors, but it should never be swallowed.

Fluoride supplements are usually used in children who are at high risk for dental decay. They are taken in small amounts. The daily dose ranges from 0.25 to 1 milligram. The amount is based on the child’s age and the amount of fluoride in the water he or she drinks.

Dentists do not prescribe more than 264 milligrams of fluoride tablets at a time. That’s because the toxic dose of fluoride for a 2-year-old child weighing 22 pounds is 320 milligrams. To avoid any chance of accidental overdose, do not stock up on fluoride tablets in your home. If you have any questions regarding fluoride risks, talk to your dentist or physician.

Everyone should use fluoridated toothpaste. Be careful with young children. They are more likely to swallow the toothpaste than to spit it out. Use only a pea-sized amount of toothpaste. Encourage them to spit out as much as possible. Avoid flavored toothpastes that may encourage swallowing.

Follow-Up

Don’t eat, drink or smoke for at least 30 minutes after a professional fluoride treatment. This helps to increase the fluoride’s contact with the teeth.