Fluoride therapy is the delivery of fluoride to the teeth topically or systemically in order to prevent tooth decay (dental caries) which results in cavities. Most commonly, fluoride is applied topically to the teeth using gels, varnishes, toothpaste/dentifrices or mouth rinse.
How Fluoridation Works
All fluoridation methods provide low concentrations of fluoride ions in saliva, thus exerting a topical effect on the plaque fluid. Fluoride combats the decay primarily by the formation fluorapatite via remineralization of enamel. The fluoride ions reduce the rate of tooth enamel demineralization, and increase the rate of remineralization of the early stages of cavities. Fluoride exerts its major effect by this demineralization and remineralization cycle. Fluoride also affects the physiology of dental bacteria, although its effect on bacterial growth does not seem to be relevant to cavity prevention. Fluoride has minimal effect on cavities after it is swallowed. Technically, fluoride does not prevent cavities but rather controls the rate at which they develop. Although fluoride is the only well-documented agent with this property, it has been suggested that also adding some calcium to the water would reduce cavities further.
Types of Fluoride Treatment
The U.S. Center for Disease Control lists water fluoridation as one of the “ten greatest public health achievements of the 20th century.” Many types of fluoride therapies are known, ranging from at-home therapies (use of fluoridated toothpaste) to professionally administered, such as topical fluorides provided by dental offices, to publicly sponsored fluoridation of water or other commonly ingested materials such as salt. At-home therapies can be further divided into over-the-counter (OTC) and prescription strengths. The fluoride therapies, whether OTC or PATF, are categorized by application – dentifrices, mouthrinses, gels/ foams, varnishes, dietary fluoride supplements, and water fluoridation.
Most toothpaste today contains 0.32% (3200 ppm) fluoride, usually in the form of sodium fluoride or sodium monofluorophosphate (MFP); 100 g of toothpaste containing 0.76 g MFP equates to 0.1 g fluoride. Prescription strength fluoride toothpaste generally contains 1.1% (11,000 ppm) sodium fluoride toothpaste. This type of toothpaste is used in the same manner as regular toothpaste. It is well established that 1.1% sodium fluoride is safe and effective as a preventive of caries. This prescription dental cream is used up to three times daily in place of regular toothpaste.
The most common fluoride compound used in mouth rinse is sodium fluoride. Over-the-counter solutions of 0.05% sodium fluoride (225 ppm fluoride) for daily rinsing are available for use. Fluoride at this concentration is not strong enough for people at high risk for cavities.
Prescription mouth rinses are more effective for those at high risk for caries, but are usually counterindicated for children, especially in areas with fluoridated drinking water. However, in areas without fluoridated drinking water, these rinses are sometimes prescribed for children.
Gels and Foams
Gels and foams are used for individuals who are at high risk for caries, orthodontic patients, patients undergoing head and neck radiation, patients with decreased salivary flow, and children whose permanent molars should, but cannot, be sealed. The gel or foam is applied through the use of a mouth tray, which contains the product. The tray is held in the mouth by biting. Application generally takes about four minutes, and patients should not rinse, eat, smoke, or drink for at least 30 minutes after application.
Some gels are made for home application, and are used in a manner similar to toothpaste. The concentration of fluoride in these gels is much lower than in professional products. An imprint of a person’s teeth can be made by a dentist, who then uses that to make well fitting trays to put over their teeth. The patient can then use this to hold a fluoride treatment against their teeth overnight.
Fluoride varnish has practical advantages over gels in ease of application, a non-offensive taste, and use of smaller amounts of fluoride than required for gel applications. Varnish is intended for the same group of patients as the gels and foams. There is also no published evidence as of yet that indicates that professionally applied fluoride varnish is a risk factor for enamel fluorosis. The varnish is applied with a brush and sets within seconds. Topical application of fluoride has shown better result than systemic fluoride application to a greater extent.
Indications for Fluoride Therapy
The individual’s risk factors and the reason for treatment will determine which method of fluoride delivery is used. Consult with a dentist before starting any treatment. Indications fluoride therapy may be necessary include:
- White spots
- Moderate to high risks for developing decay
- Active decay
- Orthodontic treatment
- Additional protection for children in areas without fluoridated drinking water
- Tooth sensitivity
- When additional protection for root surfaces are necessary
- Decreased salivary flow
- Institutionalized patients
Ask your dentist if fluoride would benefit you.