Fluoride therapy is the delivery of fluoride to the teeth topically or systemically, which is designed 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.
Systemic delivery involves fluoride supplementation using tablets or drops which are swallowed. This type of delivery is rarely used where public water supplies are fluoridated, but is common (along with salt fluoridation) in some European countries.
Benefits of fluoride therapy
Fluoride therapy is commonly practiced and generally agreed upon as being useful in the modern dental field. Fluoride combats the formation of tooth decay primarily in three ways:
Fluoride promotes the remineralization of teeth, by enhancing the tooth remineralization process. Fluoride found in saliva will absorb into the surface of a tooth where demineralization has occurred. The presence of this fluoride in turn attracts other minerals (such as calcium), thus resulting in the formation of new tooth mineral.
Fluoride can make a tooth more resistant to the formation of tooth decay. The new tooth mineral that is created by the remineralization process in the presence of fluoride is actually a “harder” mineral compound than existed when the tooth initially formed. Teeth are generally composed of hydroxyapatite and carbonated hydroxyapatite. Fluorapatite is created during the remineralization process when fluoride is present and is more resistant to dissolution by acids (demineralization).
Fluoride can inhibit oral bacteria’s ability to create acids. Fluoride decreases the rate at which the bacteria that live in dental plaque can produce acid by disrupting the bacteria and its ability to metabolize sugars. The less sugar the bacteria can consume, the less acidic waste which will be produced and participate in the demineralization process.
There are many different types of fluoride therapies, which include at home therapies and professionally applied topical fluorides (PATF). 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, mouth rinses, gels/ foams, varnishes, dietary fluoridate supplements, and water fluoridation.
Fluoride, while beneficial to adults, is more important in children whose teeth are developing. As teeth are developing within their jaw bones, enamel is being laid down. Systemic ingestion of fluoride results in a greater component of fluoroapatite in the mineral structure of the enamel.
Methods of delivery
Most dentifrices today contain 0.1% (1000 ppm) fluoride, usually in the form of sodium monofluorophosphate (MFP); 100 g of toothpaste containing 0.76 g MFP (equivalent to 0.1 g fluoride). Toothpaste containing 1,500 ppm fluoride has been reported to be slightly more efficacious in reducing dental caries in the U.S. Toothpaste may cause or exacerbate perioral dermatitis most likely caused by sodium lauryl sulfate, an ingredient in toothpaste. It is suspected that SLS is linked to a number of skin issues such as dermatitis and it is commonly used in research laboratories as the standard skin irritant with which other substances are compared.
Prescription strength fluoride toothpaste generally contains 1.1% (4,950 ppm) sodium fluoride toothpaste, e.g. PreviDent 5000 Plus or booster. 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 caries preventive. This prescription dental cream is used once 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 caries.
Prescription mouth rinses are more effective for those at high risk for caries, but are usually counter-indicated 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 are used for patients 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.
GC Tooth Mousse, invented by Dr Eric Reynolds, Head of the School of Dental Science at Melbourne University, at the Royal Dental Hospital Melbourne is now considered an essential management solution for at risk patients.
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 professional products.
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.