what is fluoride

8/10/2019 What is Fluoride

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What is fluoride?

Fluoride compounds are salts that form when the element, fluorine, combines with minerals in

soil or rocks.

Uses for fluoride.

Many communities add fluoride to their drinking water to promote dental health.

If you are concerned about fluoride in a private well, please visit:

EPA's private drinking water wells website

Water Systems Council website

What are fluoride s health effects?

Exposure to excessive consumption of fluoride over a lifetime may lead to increased likelihood

of bone fractures in adults, and may result in effects on bone leading to pain and tenderness.

Children aged 8 years and younger exposed to excessive amounts of fluoride have an increased

chance of developing pits in the tooth enamel, along with a range of cosmetic effects to teeth.

This health effects language is not intended to catalog all possible health effects for fluoride.

Rather, it is intended to inform consumers of some of the possible health effects associated

with fluoride in drinking water.

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What are EPA s drinking water regulations for fluoride?

In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA to determine the

level of contaminants in drinking water at which no adverse health effects are likely to occur.These non-enforceable health goals, based solely on possible health risks and exposure over a

lifetime with an adequate margin of safety, are called maximum contaminant level goals

(MCLG). Contaminants are any physical, chemical, biological or radiological substances or

matter in water.

The MCLG for fluoride is 4.0 mg/L or 4.0 ppm. EPA has set this level of protection based on the

best available science to prevent potential health problems. EPA has set an enforceable

regulation for fluoride, called a maximum contaminant level (MCL), at 4.0 mg/L or 4.0 ppm.

MCLs are set as close to the health goals as possible, considering cost, benefits and the ability

of public water systems to detect and remove contaminants using suitable treatment

technologies. In this case, the MCL equals the MCLG, because analytical methods or treatment

technology do not pose any limitation.

EPA has also set a secondary standard (SMCL) for fluoride at 2.0 mg/L or 2.0 ppm. Secondary

standards are non-enforceable guidelines regulating contaminants that may cause cosmetic

effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in
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drinking water. EPA recommends secondary standards to water systems but does not require

systems to comply. However, states may choose to adopt them as enforceable standards. Tooth

discoloration and/or pitting is caused by excess fluoride exposures during the formative period

prior to eruption of the teeth in children. The secondary standard of 2.0 mg/L is intended as a

guideline for an upper bound level in areas which have high levels of naturally occurring

fluoride. The level of the SMCL was set based upon a balancing of the beneficial effects of

protection from tooth decay and the undesirable effects of excessive exposures leading to

discoloration.

Fluoride is voluntarily added to some drinking water systems as a public health measure for

reducing the incidence of cavities among the treated population. The decision to fluoridate a

water supply is made by the s or local municipality, and is not mandated by EPA or any other

Federal entity. The Centers for Disease Control and Prevention (CDC) provides

recommendations about the optimal levels of fluoride in drinking water in order to prevent

tooth decay.

Information about CDC's recommendations

States may set more stringent drinking water MCLGs and MCLs for fluoride than EPA.

The drinking water standards are currently under review. The Safe Drinking Water Act requires

EPA to periodically review the national primary drinking water regulation for each contaminant

and revise the regulation, if appropriate. In 2003 and as part of the first Six Year Review, EPA

reviewed the drinking water standard for fluoride and found that new health and exposure data

were available on orally ingested fluoride. EPA requested that the National Research Council

(NRC) of the National Academies of Science (NAS) conduct a review of this data and in 2006, theNRC published their evaluation in a report entitled, Fluoride in Drinking Water: A Scientific

Review of EPA's Standards. The NRC recommended that EPA update its fluoride risk assessment

to include new data on health risks and better estimates of total exposure.

In March 2010 and as part of the secondSix Year Review,the Agency indicated that the Office

of Water was in the process of developing its health and exposure assessments to address the

NRC's recommendations. The Agency finalized therisk and exposure assessments for

fluoridein January 2011 andannounced its intent to review the drinking water regulations for

fluoride to determine whether revisions are appropriate.

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How does fluoride get into my drinking water?

Some fluoride compounds, such as sodium fluoride and fluorosilicates, dissolve easily into

ground water as it moves through gaps and pore spaces between rocks. Most water supplies

contain some naturally occurring fluoride. Fluoride also enters drinking water in discharge from
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fertilizer or aluminum factories. Also, many communities add fluoride to their drinking water to

promote dental health.

A federal law called theEmergency Planning and Community Right to Know Act

(EPCRA)requires facilities in certain industries, which manufacture, process, or use significant

amounts of toxic chemicals, to report annually on their releases of these chemicals. For more

information on the uses and releases of chemicals in your state, contact the Community Right-

to-Know Hotline: (800) 424-9346.

EPA's Toxics Release Inventory (TRI) website provides information about the types and

amounts of toxic chemicals that are released each year to the air, water, and land.

END

Water fluoridationis the controlled addition offluorideto apublic water supplyto reducetooth

decay.Fluoridated water has fluoride at a level that is effective for preventing cavities; this can occur

naturally or by adding fluoride.[2]Fluoridated water operates on tooth surfaces: in the mouth it creates

low levels of fluoride insaliva,which reduces the rate at whichtooth enameldemineralizes and

increases the rate at which itremineralizesin the early stages of cavities.[3]Typically a fluoridated

compound is added to drinking water, a process that in the U.S. costs an average of about $1.02 per

person-year.[2][4]Defluoridation is needed when the naturally occurring fluoride level exceeds

recommended limits.[5]A 1994World Health Organizationexpert committee suggested a level of

fluoride from 0.5 to 1.0 mg/L (milligrams per litre), depending on climate.[6]Bottled watertypically has

unknown fluoride levels, and some domesticwater filtersremove some or all fluoride.[7]

Dental cariesremain a majorpublic healthconcern in mostindustrialized countries,affecting 60

90% of schoolchildren and the vast majority of adults.[8]Water fluoridation prevents cavities in both

children and adults,[9]with studies estimating an 1840% reduction in cavities when water fluoridation

is used by children who already have access to toothpaste and other sources of fluoride.[2]Studies

suggest that the use of water fluoridation particular in industrialized countries may be unnecessary

for caries prevention, because topical fluorides (such as in toothpaste) are widely used and caries

has become low.[3]

Although fluoridation can causedental fluorosis,which can alter the appearance ofdevelopingteethorenamel fluorosis,[3]most of this is mild and usually not considered to be of aesthetic or public-

health concern.[10]There is no clear evidence of otheradverse effectsfrom water

fluoridation.[11]Studies on adverse effects have been mostly of low quality.[11]Fluoride's effects

depend on the total daily intake of fluoride from all sources. Drinking water is typically the largest

source;[12]other methods offluoride therapyinclude fluoridation of toothpaste, salt, and milk.[13]Water
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fluoridation, when feasible and culturally acceptable, has substantial advantages, especially for

subgroups at high risk.[8]

In 1999 the U.S.Centers for Disease Control and Preventionlisted water fluoridation as one of the

ten great public health achievements of the 20th century;[14]in contrast, most European countries

have experienced substantial declines in tooth decay without its use, primarily due to the introduction

of fluoride toothpaste in the 1970s.[3]Fluoridation may be more justified in the U.S. because of

socioeconomic inequalities in dental health anddental care.[15]Public water fluoridation was first

practiced in the U.S.,[16]and has been introduced to many other countries to varying degrees,[17]with

many countries having water that is naturally fluoridated to recommended levels and others, such as

in Europe, using fluoridated salts as an alternative source of fluoride.[18]

Contents

[hide]

1 Goal 2 Implementation

3 Mechanism

4 Evidence

o 4.1 Effectiveness

o 4.2 Fluorosis

o 4.3 Safety

5 Alternatives

6 Economics

7 Ethics and politics

8 Use around the world

9 History

10 References

11 External links

Goal

Acavitystarts in a tooth's outer enamel and spreads to thedentinandpulpinside.

The goal of water fluoridation is to prevent tooth decay by adjusting the concentration of fluoride in

public water supplies.[2]Tooth decay (dental caries)is one of the most prevalentchronic

diseasesworldwide.[19]Although it is rarely life-threatening, tooth decay can cause pain and impair

eating, speaking, facial appearance, and acceptance into society,[20]and it greatly affects the quality

of life of children, particularly those of lowsocioeconomic status.[19]In mostindustrialized countries,
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tooth decay affects 6090% of schoolchildren and the vast majority of adults; although the problem

appears to be less in Africa's developing countries, it is expected to increase in several countries

there because of changing diet and inadequate fluoride exposure.[8]In the U.S., minorities and the

poor both have higher rates of decayed and missing teeth,[21]and their children have less dental

care.[22]

Once a cavity occurs, the tooth's fate is that of repeated restorations, with estimates for themedian life of anamalgamtooth fillingranging from 9 to 14 years.[23]Oral disease is the fourth most

expensive disease to treat.[24]The motivation for fluoridation of salt or water is similar to that

ofiodized saltfor the prevention ofmental retardationandgoiter.[25]

The goal of water fluoridation is to prevent a chronic disease whose burdens particularly fall on

children and the poor.[19]Its use presents a conflict between thecommon goodandindividual

rights.[26]It is controversial,[27]andopposition to ithas been based on ethical, legal, safety, and

efficacy grounds.[28]Health and dental organizations worldwide have endorsed its safety and

effectiveness.[3]Its use began in 1945, following studies of children in a region where higher levels of

fluoride occur naturally in the water.[29]Researchers discovered that moderate fluoridation prevents

tooth decay,[30]and as of 2004 about 400 million people worldwide received fluoridated water.[18]

Implementation

Fluoride monitor (at left) in a community water tower pumphouse,Minnesota,1987.

Fluoridation does not affect the appearance, taste, or smell of drinking water.[1]It is normally

accomplished by adding one of three compounds to the water: sodium fluoride, fluorosilicic acid, or

sodium fluorosilicate.

Sodium fluoride(NaF) was the first compound used and is thereference standard.[31]It is a

white, odorless powder or crystal; the crystalline form is preferred if manual handling is used, asit minimizes dust.[32]It is more expensive than the other compounds, but is easily handled and is

usually used by smaller utility companies.[33]

Fluorosilicic acid(H2SiF6) is the most commonly used additive for water fluoridation.[34]It is an

inexpensive liquidby-productof phosphate fertilizer manufacture.[31]It comes in varying
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cic_acidhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-34http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-34http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-34http://en.wikipedia.org/wiki/By-producthttp://en.wikipedia.org/wiki/By-producthttp://en.wikipedia.org/wiki/By-producthttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Reeves-31http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Reeves-31http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Reeves-31http://en.wikipedia.org/wiki/File:Fluoride-monitor-Anderson-1987.jpeghttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Reeves-31http://en.wikipedia.org/wiki/By-producthttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-34http://en.wikipedia.org/wiki/Fluorosilicic_acidhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-33http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-WFPP-theory-32http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Reeves-31http://en.wikipedia.org/wiki/Reference_standardhttp://en.wikipedia.org/wiki/Sodium_fluoridehttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Lamberg-1http://en.wikipedia.org/wiki/Minnesotahttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-extent-18http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Ripa-30http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-NICDR-29http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Pizzo-3http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Armfield-28http://en.wikipedia.org/wiki/Opposition_to_water_fluoridationhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Cheng2007-27http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-ethics-26http://en.wikipedia.org/wiki/Individual_rightshttp://en.wikipedia.org/wiki/Individual_rightshttp://en.wikipedia.org/wiki/Common_goodhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Selwitz-19http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Horowitz-25http://en.wikipedia.org/wiki/Goiterhttp://en.wikipedia.org/wiki/Mental_retardationhttp://en.wikipedia.org/wiki/Iodized_salthttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-WHA-2007-24http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Griffin-econ-23http://en.wikipedia.org/wiki/Tooth_fillinghttp://en.wikipedia.org/wiki/Amalgam_(dentistry)http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-22http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-21http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Petersen-2004-8


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strengths, typically 2325%; because it contains so much water, shipping can be expensive.[32]It

is also known as hexafluorosilicic, hexafluosilicic, hydrofluosilicic, and silicofluoric acid.[31]

Sodium fluorosilicate(Na2SiF6) is the sodium salt of fluorosilicic acid. It is a powder or very fine

crystal that is easier to ship than fluorosilicic acid. It is also known as sodium silicofluoride.[32]

These compounds were chosen for theirsolubility,safety, availability, and low cost.[31]A 1992 census

found that, for U.S. public water supply systems reporting the type of compound used, 63% of the

population received water fluoridated with fluorosilicic acid, 28% with sodium fluorosilicate, and 9%

with sodium fluoride.[35]TheCenters for Disease Control and Preventiondeveloped

recommendations for water fluoridation that specify requirements for personnel, reporting, training,

inspection, monitoring, surveillance, and actions in case of overfeed, along with technical

requirements for each major compound used.[36]

Although fluoride was once considered anessential nutrient,theU.S. National Research

Councilhas since removed this designation due to the lack of studies showing it is essential for

human growth, though still considering fluoride a "beneficial element" due to its positive impact on

oral health.[37]Since 1962, the U.S. had specified the optimal level of fluoride to range from 0.7 to

1.2 mg/L (milligrams per liter, equivalent toparts per million), depending on the average maximum

daily air temperature; the optimal level is lower in warmer climates, where people drink more water,

and is higher in cooler climates.[38]This standard, adopted in 1962, is not appropriate for all parts of

the world and is based on assumptions that have become obsolete with the rise ofair

conditioningand increased use ofsoft drinks,processed food,and other sources of fluorides. In

1994 a World Health Organization expert committee on fluoride use stated that 1.0 mg/L should be

an absolute upper bound, even in cold climates, and that 0.5 mg/L may be an appropriate lower

limit.[6]A 2007 Australian systematic review recommended a range from 0.6 to 1.1 mg/L.[10]In 2011,

the U.S. lowered its recommended level of fluoride to 0.7 mg/L.[39]

Geographical areas associated withgroundwaterhaving over 1.5 mg/L of naturally occurring fluoride, which is above

recommended levels.[10]
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Detail ofsouthern Arizona.Areas in darker blues have groundwater with over 2 mg/L of naturally occurring fluoride.

Fluoride naturally occurring in water can be above, at, or below recommended levels. Rivers and

lakes generally contain fluoride levels less than 0.5 mg/L, but groundwater, particularly in volcanic or

mountainous areas, can contain as much as 50 mg/L.[12]

Higher concentrations offluorineare foundinalkalinevolcanic,hydrothermal,sedimentary,and otherrocksderived from highly

evolvedmagmasandhydrothermal solutions,and this fluorinedissolvesinto nearby water as

fluoride. In most drinking waters, over 95% of total fluoride is the Fion,with themagnesium

fluoridecomplex(MgF+) being the next most common. Because fluoride levels in water are usually

controlled by the solubility offluorite(CaF2), high natural fluoride levels are associated withcalcium-

deficient, alkaline, andsoft waters.[40]Defluoridation is needed when the naturally occurring fluoride

level exceeds recommended limits. It can be accomplished bypercolatingwater through granular

beds ofactivated alumina,bone meal,bone char,ortricalcium phosphate;by coagulation withalum;

or byprecipitationwithlime.[5]

Pitcherorfaucet-mounted water filters do not alter fluoride; the more-expensivereverse

osmosisfilters remove 6595% of fluoride, anddistillationfilters remove all fluoride.[7]U.S.

regulations forbottled waterdo not require disclosing fluoride content, so the effect of always

drinking it is unknown.[7]Surveys of bottled water in Cleveland and in Iowa found that most contained

well below optimal fluoride levels;[41]a survey inSo Paulo, Brazil,found large variations of fluoride,

with many bottles exceeding recommended limits and disagreeing with their labels.[42]

Mechanism

Fluoride exerts its major effect by interfering with the demineralization mechanism of tooth decay.

Tooth decay is aninfectious disease,the key feature of which is an increase withindental plaqueof

bacteria such asStreptococcus mutansandLactobacillus.These produce organic acids when

carbohydrates, especially sugar, are eaten.[43]When enough acid is produced to lower thepHbelow

5.5,[44]the acid dissolvescarbonatedhydroxyapatite,the main component of tooth enamel, in a

process known as demineralization . After the sugar is gone, some of the mineral loss can be
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note-42http://en.wikipedia.org/wiki/Infectious_diseasehttp://en.wikipedia.org/wiki/Infectious_diseasehttp://en.wikipedia.org/wiki/Infectious_diseasehttp://en.wikipedia.org/wiki/Dental_plaquehttp://en.wikipedia.org/wiki/Dental_plaquehttp://en.wikipedia.org/wiki/Dental_plaquehttp://en.wikipedia.org/wiki/Streptococcus_mutanshttp://en.wikipedia.org/wiki/Streptococcus_mutanshttp://en.wikipedia.org/wiki/Streptococcus_mutanshttp://en.wikipedia.org/wiki/Lactobacillushttp://en.wikipedia.org/wiki/Lactobacillushttp://en.wikipedia.org/wiki/Lactobacillushttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Featherstone-43http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Featherstone-43http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Featherstone-43http://en.wikipedia.org/wiki/PHhttp://en.wikipedia.org/wiki/PHhttp://en.wikipedia.org/wiki/PHhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Cury-44http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Cury-44http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Cury-44http://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Hydroxyapatitehttp://en.wikipedia.org/wiki/Hydroxyapatitehttp://en.wikipedia.org/wiki/Hydroxyapatitehttp://en.wikipedia.org/wiki/File:Southern-Arizona-fluoride-groundwater.jpeghttp://en.wikipedia.org/wiki/Hydroxyapatitehttp://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Cury-44http://en.wikipedia.org/wiki/PHhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Featherstone-43http://en.wikipedia.org/wiki/Lactobacillushttp://en.wikipedia.org/wiki/Streptococcus_mutanshttp://en.wikipedia.org/wiki/Dental_plaquehttp://en.wikipedia.org/wiki/Infectious_diseasehttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-42http://en.wikipedia.org/wiki/S%C3%A3o_Paulo,_Brazilhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-41http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Hobson-7http://en.wikipedia.org/wiki/Bottled_waterhttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Hobson-7http://en.wikipedia.org/wiki/Distillationhttp://en.wikipedia.org/wiki/Reverse_osmosishttp://en.wikipedia.org/wiki/Reverse_osmosishttp://en.wikipedia.org/wiki/Faucethttp://en.wikipedia.org/wiki/Pitcher_(container)http://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Taricska-5http://en.wikipedia.org/wiki/Lime_(mineral)http://en.wikipedia.org/wiki/Precipitation_(chemistry)http://en.wikipedia.org/wiki/Alumhttp://en.wikipedia.org/wiki/Tricalcium_phosphatehttp://en.wikipedia.org/wiki/Bone_charhttp://en.wikipedia.org/wiki/Bone_mealhttp://en.wikipedia.org/wiki/Activated_aluminahttp://en.wikipedia.org/wiki/Percolatinghttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-40http://en.wikipedia.org/wiki/Soft_waterhttp://en.wikipedia.org/wiki/Calciumhttp://en.wikipedia.org/wiki/Fluoritehttp://en.wikipedia.org/wiki/Complex_(chemistry)http://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Solvationhttp://en.wikipedia.org/wiki/Ore_genesis#Hydrothermal_processeshttp://en.wikipedia.org/wiki/Magmahttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Sedimentaryhttp://en.wikipedia.org/wiki/Hydrothermal_circulation#Hydrothermal_ore_depositshttp://en.wikipedia.org/wiki/Volcanic_rockhttp://en.wikipedia.org/wiki/Alkalinehttp://en.wikipedia.org/wiki/Fluorinehttp://en.wikipedia.org/wiki/Water_fluoridation#cite_note-Fawell-12http://en.wikipedia.org/wiki/Southern_Arizona


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