Fluoride therapy

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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. Systemic delivery involves fluoride supplementation using water, salt, tablets or drops which are swallowed. Tablets or drops are rarely used where public water supplies are fluoridated. Controversy surrounds water fluoridation.

Contents 1 Benefits of fluoride therapy 2 Health risks 2.1 Overdose 2.2 Fluorosis 2.3 Reproductive and developmental 2.4 Neurological 2.5 Endocrine 2.6 Gastrointestinal, renal, and liver 3 Methods of delivery 3.1 Toothpaste 3.2 Mouth rinses 3.3 Gels/foams 3.4 Varnish 3.5 Dietary fluoride supplements 3.6 Indications for fluoride therapy 4 Water fluoridation 5 Fluoride conversion chart 6 Citations 7 References

[edit] Benefits of fluoride therapy

Fluoride therapy is commonly practiced and generally agreed upon as being useful by dentists. Fluoride combats the formation of tooth decay primarily in three ways:

1. 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.
2. 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).
3. 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, mouthrinses, 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.

[edit] Health risks

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There are several risks involved in fluoride therapy, including overdose, dental fluorosis, skeletal fluorosis, reproductive and developmental effects, neurological effects, and endocrine effects.

[edit] Overdose

In 1974 a 3-year old child consumed 45 cubic centimeters of 2% fluoride solution, estimated to be triple the fatal amount, and then died.^[1]

[edit] Fluorosis

Previous research has considered the effect of dental fluorosis cosmetic, but a recent report by National Research Council (NRC) claims that severe dental fluorosis can be considered a "toxic effect" which increases the prevalence of caries (106). Systemic fluoride leads to an increase in bone density but a deterioration in bone quality (133), and the NRC claims that "the weight of evidence supports the conclusion that lifetime exposure to fluoride at drinking water concentrations of 4 mg/L and higher is likely to increase fracture rates in the population" (165). Skeletal fluorosis is a "musculoskeletal disease with high morbidity", with stage III described as "crippling" (171. The risk of skeletal fluorosis is higher for those with reduced renal function (172. Bone fluoride levels associated with stage II and III fluorosis can be reached from lifetime consumption of fluoridated water at 2 and 4 mg/L (179), but there's insufficient data to gauge the risk quantitatively. Research on arthritis is mixed, but overall fluoride appears to have a small negative effect on arthritis at "therapeutic doses" and none at "environmental doses" (177, 178).

[edit] Reproductive and developmental

At levels beginning around 5-10 mg/L, above the U.S. maximum of 4 mg/L, fluoride has shown negative reproductive effects in rats and mice (181-204). These effects are reduced when vitamin C or E is administered concurrently (185). Men with high exposure to fluoride have significantly less testosterone (192). However, the NRC ultimately concludes that the studies have shortcomings, and that the toxic impacts occur at high levels (204).

[edit] Neurological

Several Chinese studies have been done on the cognitive effects of fluoride, and all found that in areas with high fluoride, the people have lower IQ (205). Masters and Coplan found that fluoridating water with silicofluorides, which are usually an industrial byproduct, correlates with a higher exposure to lead (209). Their research was contested, but a dissertation in 1975 showed that silicofluorides act differently than fluoride salts on the body (210). Some limited science suggests that fluoride increases the risk of Alzheimer's through its bonding with aluminum and its neurochemical effects (212). Rats administered fluoride have been shown to have more aluminum in the brain, twice as much as the control rats (217). The NRC claims that "many of the untoward effects of fluoride are due to the formation of AlFx complexes" (219).

[edit] Endocrine

Fluoride can be considered a hormone disruptor, which can cause varying effects on humans. It accumulates faster in the thyroid gland than any other soft tissue besides the kidney, and although it was thought to compete with iodine for the thyroid, this is no longer believed (226). Evidence suggests that fluoride's toxic impact on the thyroid gland increases with iodine deficiency (227), but fluoride's ultimate impact on the thyroid cannot yet be quantified or predicted (266). An animal study has found that fluoride collects in the pineal gland (264), and epidemiological studies have found that areas with high fluoride levels have higher levels of goiter (229).

[edit] Gastrointestinal, renal, and liver

Consumption of 20 mg/L and up has been studied through accidental overfeeds. Generally most of those affected by drinking fluoride at these concentrations report gastroenteritis (269-274). The kidney is more susceptible to fluoride toxicity than other organs (280), and persons with renal impairment may accumulate fluoride in their body faster than others (292). There is less evidence on the damage to the liver, but the Chinese researchers have noted fluoride causing damage to the liver and kidney in children.^[2]

[edit] Methods of delivery

[edit] Toothpaste

Most toothpaste today contains 0.1% (1000 ppm) fluoride, usually in the form of sodium monofluorophosphate (MFP); 100 g of toothpaste containing 0.76 g MFP equates to 0.1 g fluoride. 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.

[edit] Mouth rinses

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 counterindicated for children, especially in areas with fluoridated drinking water. However, in areas without fluoridated drinking water, these rinses are sometimes prescribed for children.

[edit] Gels/foams

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.

[edit] Varnish

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.

[edit] Dietary fluoride supplements

Dietary fluoride supplements in the form of tablets, lozenges, or liquids (including fluoride-vitamin preparations) are used primarily for children in areas without fluoridated drinking water.

Fluoride does not have a defined Recommended Dietary Allowance. ^[3] Instead, there is a Fluoride Supplement Dosage Schedule, which has been approved by the American Dental Association, American Academy of Pediatrics and American Academy of Pediatric Dentistry.

Age	Fluoride Ion Level in Drinking Water (ppm)*
	<0.3 ppm	0.3-0.6 ppm	>0.6 ppm
Birth-6 months	None	None	None
6 months-3 years	0.25 mg/day**	None	None
3-6 years	0.50 mg/day	0.25 mg/day	None
6-16 years	1.0 mg/day	0.50 mg/day	None

.* 1.0 ppm = 1 mg/liter

.** 2.2 mg sodium fluoride contains 1 mg fluoride ion

[edit] Indications for fluoride therapy

Depending on 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.

• white spots
• Moderate to high risk patients for developing decay
• Active decay
• Orthodontic treatment
• Additional protection if necessary for children in areas without fluoridated drinking water
• To reduce tooth sensitivity
• Protect root surface
• Decreased salivary flow
• Institutionalized patients

[edit] Water fluoridation

Fluoridation means the addition of a chemical to increase the concentration of fluoride ions in drinking water to reduce the incidence of tooth decay. [1] Toxic reactions can occur if fluoride levels are too high. Nevertheless, in April 1999, the Centers for Disease Control and Prevention proclaimed community water fluoridation as one of 10 great public health achievements of the 20th century.

Some studies suggest that fluoridation is not sufficiently effective in treating dental cavities. [2][3] Civil libertarians argue that releasing fluoride compounds into a municipal water takes away individual choice as to the substances a person ingests, and amounts to mass medication. See the water fluoridation opposition article for more details.

Grand Rapids, Michigan was the first city in the United States to add fluoride chemicals to the drinking water, doing so in 1945.

[edit] Fluoride conversion chart

APF (10)(%)(1000)	ppm
1.1%	10,000
1.23%	12,300
NaF (4.5)(%)(1000)	ppm
0.05%	225
0.20%	900
0.44%	1,980
1.0 %	4,500
1.1%	4,950
2.0%	9,000
5.0%	22,500
SnF2 (2.4)(%)(1000)	ppm
0.40%	960
0.63%	1,512

[edit] Citations

[edit] References

• Centers for Disease Control and Prevention. Recommendations for Using Fluoride to Prevent and Control Dental Caries in the United States.
• Committee on Fluoride in Drinking Water, National Research Council. (2006). Fluoride in Drinking Water: A Scientific Review of EPA's Standards. National Academies Press.
• government guidelines
• Fluoride History History of fluoride therapy including early patents
• Clark CD. Appropriate use of fluorides in the 1990s. J Canad Dent Assoc. 1993;59:272-279.
• Hawkins R, Locker D, Noble J, Kay EJ. Prevention. Part 7: Professionally applied topical fluorides for caries prevention. British Dental J. 2003: Vol. 195, No 6: 313-317.
• Moran R, Saemundsson S. Fluoride Varnish: An alternative to traditional topical fluoride therapy. Department of Pediatric Dentistry, University of North Carolina 1996
• Stookey GK. Review of fluorosis risk of self-applied topical fluorides: dentifrices, mouthrinses and gels. Community Dent Oral Epidemiol. 1994;22:282-286