testLetter to Health Professsionals on Fluoride (Version 2)

7/27/2019 testLetter to Health Professsionals on Fluoride (Version 2)

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Alison McKellar79#Mechanic#Street,#Camden,#Maine#04843#Phone:##(207)#619>1530##!#E>Mail:#:#[email protected]#

Dear Mid-Coast Health Professional,

Almost 50 years ago, in an effort to address high rates of tooth decay among children, thiscommunity made a decision to start adding fluoride to our tap water, which originates from Mirror Lakeand serves about half the residents in the towns of Camden, Rockport, Rockland, Thomaston, and smallparts of Owls Head and Warren. After spending some time reviewing the history of the scientific researchand public policies regarding fluoride, I believe its time for our community to re-examine what we havelearned and what has changed in the 44 years since fluoridation began here. I am writing to ask that, as alocal health professional, you take a moment to review the current literature on the subject so as to beprepared for any questions you might receive from patients in the coming months.

Like most people, I had never thought much about fluoride. Recently, I began to wonder if my 3-year-old

son should start using fluoridated toothpaste. A quick web search will tell you that children under the ageof 2 should not, and the instructions on the back of the tube that I use say that children from 2-6 shoulduse only a pea-sized amount and be monitored by an adult to minimize swallowing. The label also reads,"If you accidentally swallow more than used for brushing, seek professional help or contact a poison control centerimmediately." Well, even with constant monitoring, my 3 year old accidentally swallows almost all thetoothpaste that goes in his mouth, so I wanted to know exactly how much fluoride he would be likely toingest and how much would be too much. At that point, water fluoridation wasn't even on my radar. Ifound that a pea-sized amount of typical fluoride toothpaste (1000 ppm fluoride) contains about .25 mg offluoride, roughly the same amount of fluoride as 10.5 ounces of our tap water, which averages .8 mg perliter. This came as a surprise to me, so I wanted to know a little more.

What is fluoride? How much is enough for a 3 year old? How much is too much?

It turns out that these are not easy questions to answer and experts disagree. What we do know is that the

CDC reports that 41% of adolescents (12-15 year olds) now have some form of dental fluorosis , apermanent staining of the enamel caused by the ingestion of too much fluoride during the years when theteeth are developing. This is nearly double the figure that was reported 20 years ago and 4-5 times whatwas predicted when fluoridation first began.

In 2007, the ADA and the AAP released a warning to parents saying that babies who are exclusivelybottle fed with formula reconstituted with fluoridated water may be at an increased risk for dentalfluorosis. They suggest using fluoride-free or low fluoride water if parents are concerned. Although I waslucky enough to breastfeed my own children, I know that this is not a reality for some, and buying bottledwater is unrealistic for many low income parents. Further, no pediatrician or maternity nurse ever advisedme that, if I stopped breastfeeding, I should consider mixing my babys formula with fluoride free water.Even when a lactating mother drinks fluoridated water, her breast milk contains almost no fluoride (about4 parts per billion), which means that in many cases, bottle fed babies may be getting up to 250 timesas much fluoride as breastfed babies. The ADA and the AAP have generally stated that the permanentstaining of the tooth enamel is only cosmetic, yet there is no scientific consensus on how to categorizedental fluorosis. Since we know that ingested fluoride is also stored commulatively in other parts of thebody, such as bones and the pineal gland, many experts view dental fluorosis as a biomarker for othertypes of fluoride toxicity. To quote Dr. Hardy Limeback, Head of Preventive Dentistry at the Universityof Toronto, it is illogical to assume that tooth enamel is the only tissue affected by low daily doses of fluorideingestion."

Over the past several months, I have researched this issue extensively. I have consulted countless medicaljournals, performed MedLine searches of scholarly, peer-reviewed research, met multiple times with RickKnowlton and others from the Maine Water Company, spoken with the Director of the Maine Drinking


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Water Program, and read newspaper archives relating to the history of fluoridation in our water district. Ibegan my research 100% open-minded. In fact, I was swayed in the direction of favoringfluoridation. After all, I have fluoridated water in my own home and fluoride removal is expensive. Unlikechlorine, it cannot be removed by a simple Brita filter. I've been drinking it, giving it to my 3 year old, andeven prided myself on my eco-conscious avoidance of bottled water. In general, I tend to side with thegovernment on most public health measures. I vaccinate my children, etc, etc... Still, after reading theopinions of many experts on both sides of this issue, it seems like a strange way to prevent tooth decay inour community, a community in which only 50% of the population is served by municipal water.

As a 29 year old mother of a baby and toddler who grew up in the area, graduated from CHRHS, andmoved back to Camden about 5 years ago, I was a little surprised not to have heard more aboutfluoridation in the past. No water bill or newsletter from the water company ever mentioned anythingabout the water being fluoridated. New Hampshire recently passed legislation requiring that watercustomers be warned that mixing infant formula with tap water could increase the risk of fluorosis, buthere, no such policy is in place. Was I the only one who didnt know that something (a non-nutrient) isbeing added to our water for a purely dental benefit? Yet in my discussions with others my age, I've foundthat many people who are not old enough to have been a part of the initial debate simply do not know thatour water is fluoridated, much less why. Even some health professionals do not realize that we are afluoridated district. Most doctors and nurses I have spoken with havent thought about fluoridation in along time, and dont realize that many respected scientists and dentists, who once promoted thepractice, have changed their minds.

It has been almost fifty years since Camden, Rockland, and Thomaston approved fluoridation by a narrowmargin; having twice previously voted the measure down. Although the debate continues, one thing isvery clear to anyone who reviews the Camden Herald and Courier Gazette for the years of 1968 and 1969:The arguments used to promote it have changed vastly in the 44 years since the practice beganhere. I have included copies of health board statements and advertisements promoting fluoridation thatappeared in the Camden Herald and Courier Gazette in 1968 and 1969. At that time, doctors believed thatfluoride worked like an essential nutrient, that its benefit was primarily systemic, and that it wouldprevent all sorts of things, from tooth decay to bone fractures to arteriosclerosis. Today, even staunchadvocates of fluoridation recognize that most of those things turned out not to be true, and that fluorideworks much differently than we originally believed.

Fifty years ago, not a single fluoride toothpaste was available, and water fluoridation was considered theonly cost effective way of delivering fluoride to those who wanted it. We now have access to fluoride invirtually all toothpastes, and its widespread use as a pesticide (as sulfuryl fluoride and cryolite) leads tohigh levels of the chemical in unexpected places, such as non-organic grape juice. Since fluoride contentcan vary widely, and is not required to be labeled, it is next to impossible for people to figure out howmuch they and their children are getting. Few health professionals, including pediatricians and dentists,have been trained to assess all sources of fluoride in adults and childrens diets, such as tea, certain wheatproducts, and mechanically deboned chicken. The AAP supports labeling requirements for fluoridecontent in foods and beverages but since fluoride content can vary drastically, there has been littleheadway made in this area.

We now know that fluoride is not a nutrient and that its dental benefit is primarily topical. We also knowthat most countries, including 97% of Western Europe, have chosen not to fluoridate their water.Dentists often note the differences they see between fluoridated and non-fluoridated areas, yet data revealsthat many of these differences are socioeconomic. Tooth decay has rapidly decreased worldwide, influoridated and non-fluoridated countries alike, and World Health Organization data show no difference in

tooth decay levels between countries that practice fluoridation and countries that dont.Very few of us know that the fluoridating agent used here, like in most places, is not naturally occurringcalcium fluoride nor even pharmaceutical grade sodium fluoride, as most people expected it would be. Ihave verified with the Maine Water Company that the chemical used is hydrofluorosilicic acid, ahighly corrosive byproduct of the phosphate fertilizer industry. Our fluoride originates in phosphatefertilizer plants owned by Mosaic Fertilizer Company in Central Florida, and is shipped via railcar toBorden and Remington in Boston before being transported in a designated tanker truck to us, and is oftencontaminated with detectable amounts of arsenic, lead, and other contaminants. It requires its own specialroom at the water treatment facility because of its toxicity, and rapidly eats through metal and pavement.Because it is so acidic, fluoridated water requires treatment with additional amounts of caustic soda


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(sodium hydroxide) to normalize the pH of the finished drinking water so thatit doesnt corrode our pipes and leach lead and copper. Still research indicatesa troubling link between fluoridation chemicals and elevated blood lead levelsin children.

Phosphate mining has disastrous implications for Floridians, and the overuseof phosphate fertilizer has serious implications for drinking watereverywhere. In Florida, phosphate strip mining has been linked to sinkholes,

as well as to the pollution of the Florida aquifer, the primary drinking watersource for many Floridians. To know that we are adding something to thewater that is part of a process that jeopardizes the drinking water of others isunsettling to me, not to mention the increase in our carbon footprint broughtabout by the transporting of the chemicals, and the risk that a spill wouldpose to our health and ecosystem.

I wont spell out all the possible areas of concern. As a health professional, youcan easily assess the information for yourself and I am including a copy of aScientific American article from 2007 which provides a nice overview of theevolution of this debate and the way that fluoride works, as well as a fewother abstracts and articles from my research that illustrate some of thethings I mentioned earlier. I plan to write a letter to the city councils of the fivetown water district, but wanted to also reach out to the dental and medical

community to get your thoughts on this important issue.

Thank you for taking the time to review this letter and some of the materialI've included. I have printed everything at my own expense and haveconducted all my research mainly while breastfeeding my now 9 month old son over thepast few months. I would be eager to speak with you or provide additionalcopies of any of this information. I can be reached by email or phone.

Sincerely,

Alison McKellar

(207) [email protected]


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74 SCIENTIF IC AMERICAN January 2008

PUBLICHEALTH

Long before the passionate debates over cig-

arettes, DDT, asbestos or the ozone hole,

most Americans had heard of only one

environmental health controversy: fluoridation.

Starting in the 1950s, hundreds of communities

across the U.S. became embroiled in heated bat-

tles over whether fluoridesionic compounds

containing the element fluorineshould be

added to their water systems. On one side was

a broad coalition of scientists from government

and industry who argued that adding fluoride

to drinking water would protect teeth against

decay; on the other side were activists who con-

tended that the risks of fluoridation were inad-

equately studied and that the practice amount-

ed to compulsory medication and thus was a

violation of civil liberties.

The advocates of fluoride eventually carried

the day, in part by ridiculing opponents such as

the right-wing John Birch Society, which called

fluoridation a communist plot to poison Amer-

ica. Today almost 60 percent of the U.S. popu-

lation drinks fluoridated water, including resi-

dents of 46 of the nations 50 largest cities. Out-

side the U.S., fluoridation has spread to Canada,

the U.K., Australia, New Zealand and a few

other countries. Critics of the practice have gen-

erally been dismissed as gadflies or zealots by

mainstream researchers and public health agen-

cies in those countries as well as the U.S. (In

other nations, however, water fluoridation is

rare and controversial.) The U.S. Centers for

Disease Control and Prevention even lists water

fluoridation as one of the 10 greatest health

achievements of the 20th century, alongside

vaccines and family planning.

Now, though, scientific attitudes toward fluo-

ridation may be starting to shift in the country

where the practice began. After spending more

than two years reviewing and debating hun-

dreds of studies, a committee of the National

Research Council (NRC) released a report in

2006 that gave a tinge of legitimacy to some

longtime assertions made by antifluoridation

campaigners. The report concluded that the En-

vironmental Protection Agencys current limit

KEY CONCEPTS

I Researchers are intensify-ing their scrutiny of fluo-

ride, which is added to

most public water sys-

tems in the U.S. Some

recent studies suggest

that overconsumption of

fluoride can raise the risks

of disorders affecting

teeth, bones, the brain

and the thyroid gland.

I A 2006 report by a com-mittee of the National

Research Council recom-

mended that the federal

government lower its cur-

rent limit for fluoride in

drinking water because of

health risks to both chil-

dren and adults.

The Editors

New research indicates that a cavity-fightingtreatment could be risky if overused

By Dan Fagin

Second Thoughts about

AARONGOODMAN

2007 SCIENTIFIC AMERICAN, INC.


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www.Sc iAm.com SCIENTIF IC AMERICAN 75

for fluoride in drinking waterfour milligrams

per liter (mg/L)should be lowered because of

health risks to both children and adults. In chil-

dren, consistent exposure to fluoride at that lev-

el can discolor and disfigure emerging perma-

nent teetha condition called dental fluorosis.

In adults, the same fluoride level appears to in-

crease the risk of bone fracture and, possibly, of

moderate skeletal fluorosis, a painful stiffening

of the joints. Most fluoridated water contains

much less fluoride than the EPA limit, but the sit-

uation is worrisome because there is so much

uncertainty over how much additional fluoride

we ingest from food, beverages and dental prod-

ucts. What is more, the NRC panel noted that

fluoride may also trigger more serious health

problems, including bone cancer and damage to

the brain and thyroid gland. Although these ef-

fects are still unproved, the panel argued that

they deserve further study.

The largest long-running investigation of the

effects of fluoride is the Iowa Fluoride Study, di-

pTOO MUCH OF A GOOD

THING: Fluoride is in manyfoods, beverages anddental products. Theubiquity of the cavity-fighting chemical canresult in overconsump-tion, particularly amongyoung children.



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rected by Steven M. Levy of the University of

Iowa College of Dentistry. For the past 16 years

Levys research team has closely tracked about

700 Iowa children to try to tease out subtle ef-

fects of fluoridation that may have been over-

looked by previous studies. At the same time,

Levy is also leading one of the most extensive

efforts ever to measure fluoride concentrations

in thousands of productsincluding foods,

drinks and toothpastesto develop credible es-

timates of typical fluoride intake.

It is a maddeningly complex area of research

because diets, toothbrushing habits and water

fluoridation levels vary so much and also be-

cause genetic, environmental and even cultural

factors appear to leave some people much more

susceptible to the effects of fluorideboth pos-

itive and negativethan others. Despite all the

uncertainties, however, Levy and some other

fluoride researchers have come around to the

view that some children, especially very young

ones, are probably getting more fluoride than

they should. Most of those scientists, including

Levy, still support water fluoridation as a proved

method of controlling tooth decay, especially in

populations where oral hygiene is poor. But the

researchers also believe that in communities

with good dental care the case for fluoridation

is not as strong as it used to be. Instead of just

pushing for more fluoride, we need to find the

right balance, Levy says.

The Advent of FluorideFramed toothpaste advertisements from more

than half a century ago hang on the walls of

Levys conference room. One touting Pebeco

Toothpaste reads: Do you want your teeth to

ache and get ugly? Another asserts that Col-

gate Chlorophyll Toothpaste Destroys Bad

Breath. They are artifacts of the prefluoride

era, when tooth decaycalled caries in the par-

lance of dentistrywas pervasive and tooth-

pastes were marketed with questionable medi-

cal claims.

The introduction of fluoride changed all that.

In 1945 Grand Rapids, Mich., became the first

city to fluoridate its water supply. Ten years lat-

er Procter & Gamble introduced Crest, the first

fluoridated toothpaste, which contained stan-

nous fluoride (a compound with one atom of tin

and two of f luorine). Colgate-Palmolive fol-

lowed in 1967 by modifying its Colgate brand

with what has become one of the dominant cav-

ity-fighting ingredients in toothpastes: sodium

monofluorophosphate. Instead of sticking with

the fluoride salts found in toothpastes and fa-

[TRENDS]

FLUORIDATION ACROSS AMERICAWater fluoridation has spread across the

U.S. since its introduction in 1945. In 2002,

the latest year for which data are available,

Americans receiving fluoridated water rep-

resented 67 percent of all people suppliedby public water systems and 59 percent of

the total population. Fluoridation is most

prevalent in the District of Columbia (100

percent) and Kentucky (99.6 percent) and

least common in Hawaii (8.6 percent) and

Utah (2.2 percent).

[THE AUTHOR]

Dan Faginis an associate profes-sor of journalism and director of

the Science, Health and Environ-

mental Reporting Program at New

York University. A former environ-

mental and science writer for

Newsday, his articles on cancer

epidemiology won the AAAS

Science Journalism Award in 2003.

Fagin is co-author of Toxic Decep-

tion (Common Courage Press,

1999) and is working on a book

about gene-environment interac-

tions and the childhood cancer

cluster in Toms River, N.J.

59%oftheU.S.populationreceivedfluoridatedwaterin2002

WA

OR

ID

MT

WY

NV

CA

UT

AZ

CO

NM

TXAK

OK

KS

NE

SD

ND

MN

M

NY

VTNH

MA

NJ

DEMD

CTRI

PA

WI

MI

ILIN

OH

WVVA

KY

TN

IA

MO

AR

LA

MS

FL

AL GA

SC

NC

HI

PERCENTAGE OF STATE POPULATIONS RECEIVING FLUORIDATED WATER, 2002

< 25% 25%49% 50%75% >75%

Total U.S. populationSupplied by public water systems*Receiving fluoridated water

FLUORIDATION RISING IN THE U.S.

300

200

100

01945 1965 1985 2002

Year

NumberofPe

ople(millions)

*Dat a on pub lic wat er s yst ems not ava ila ble bef ore 196 4

COURTESYOFANNAFAGIN(Fagin);LUCYREADING-IK

KANDA(mapandgraph);MOODBOARD/CORBIS(paperclip)



8/37


vored by dentists in office treatments, most wa-

ter suppliers eventually switched to the cheaper

option of fluoridating with silicofluorides such

as hexafluorosilicic acid, a by-product of a fer-

tilizer manufacturing process in which phos-

phate ores are treated with sulfuric acid.

By the 1970s and 1980s America was awashin various forms of fluoride, and fluoridation

had become the cornerstone of preventative

dentistry in most English-speaking countries.

Exactly why and how much caries incidence de-

creased during the same period is a matter of

fierce debate, but the consensus among dental

researchers is that the decline was steep and that

fluoride deserved much of the credit.

That was the culture in which Levy got his

start in public health dentistry in the mid-1980s.

Colgate-Palmolive funded his early research,

which had the effect of encouraging more fluo-

ride use in dental offices. But as American den-

tists began to see fewer cavities and more fluo-

rosis on the teeth of their young patients, Levy

started to wonder whether children were get-

ting too much of a good thing. There was a

transition in my own thinking from more fluo-

ride is definitely our goal to making sure we un-

derstand where the right balance is between

caries and fluorosis.

Fluorides role in causing one disease and de-

terring another is rooted in the fluorine ions pow-

erful attraction to calcium-bearing tissues in the

body. In fact, more than 99 percent of ingested

fluoride that is not quickly excreted ends up in

bones and teeth. Fluoride inhibits cavities through

two separate mechanisms. First, fluoride that

touches the enamelthe hard, white outer layer

of the teethbecomes embedded in the crystal-

line structures of hydroxylapatite, the main min-

eral component of teeth and bones. The fluorine

ions replace some of the hydroxyl groups in the

hydroxylapatite molecules of the enamel, and this

substitution makes teeth slightly more resistant

to the enamel-dissolving acid excreted by bacte-

ria in the mouth as they consume food remnants.

Second, the fluoride on the surface of teeth serves

as a catalyst that enhances the deposition of cal-

cium and phosphate, making it easier for the body

to continually rebuild the enamel crystals that the

bacteria are dissolving.

Fluoride has a very different effect, however,

when large doses are ingested by young children

whose permanent teeth are still developing and

have not yet erupted. The key proteins in early

tooth formation are called amelogenins, which

regulate the formation of hydroxylapatite crys-

Debating the EffectsThe U.S. Centers for Disease Control and

Prevention has hailed fluoridation as one

of the 10 greatest public health achieve-

ments of the 20th century, claiming that

the addition of the chemical to drinking

water has been one of the main reasons

for the decline in tooth decay over thepast three decades (measured here by the

number of decayed, missing or filled

teeth in 12-year-olds). Rates of tooth

decay have also plunged, however, in

many countries where public water sys-

tems are not fluoridated. In some of

these nations, fluoride added to foods,

beverages and dental products may

account for part of the decline.

Fluorides role in combating tooth decay is rooted in the ions powerful

attraction to enamel, the hard, white outer layer of the teeth.

[FOCUS ON TEETH]

p With Fluoride

The topical application of fluoride to theteeth has two effects. First, the fluorideions replace some of the hydroxyl groups inthe hydroxylapatite molecules, creatingfluorapatite crystals that are slightly moreresistant to the enamel-dissolving acid ex-

creted by the bacteria. Second, the fluorideon the surface of teeth serves as a catalystthat enhances the deposition of calciumand phosphate, thus remineralizing dam-aged enamel and combating decay.

FIGHTING CAVITIES

p Without Fluoride

The primary mineral in enamel is hydroxylap-atite, a crystal composed of calcium, phos-phorus, hydrogen and oxygen. When foodremnants become lodged between teeth,bacteria consume the sugars and excrete lac-tic acid, which can lower the pH of the mouth

enough to dissolve the hydroxylapatite. Ifthe rate of dissolution is higher than the rateof remineralizationthe deposition of calci-um and phosphate ions from saliva onto theenamelthen cavities will form in the teeth.

Enamel

Gums

Acid excretedby bacteria

Bloodvessels

Fluoride ions

applied to teethCalcium ionsPhosphate ions

Fluoride ions

Foodremnant

Calcium andphosphate ions

Enhanceddeposition ofcalcium andphosphate

FluoridatedU.S.AustraliaNew Zealand

UnfluoridatedBelgiumFinlandItaly

TOOTH DECAY INDEX

(number of decayed, missingor filled teeth in 12-year-olds)

20051975

8

7

6

5

4

3

2

1

0

Year1985 1995

ANDREWS

WIFT(teeth);LUCYREADING-IKKANDA(graph)



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tals. As a crystal matrix forms, the amelogenins

break down and are removed from the matur-

ing enamel. But when some children consume

high doses of fluoride, which is absorbed

through the digestive tract and delivered by the

bloodstream to the developing teeth, the bio-

chemical signaling goes awry and the proteins

remain inside the budding tooth longer than

usual, thereby creating gaps in the crystalline

enamel structure. As a result, when a fluorosed

tooth finally erupts it is often unevenly colored,

with some portions whiter than othersa visu-

al effect caused by light refracting off the po-

rous enamel. In more severe cases, the surface

of the tooth is pitted and the stains are brown.

Nutrition and genetics can influence the risk of

fluorosis, but the most important factor by far

is the amount of fluoride ingested.

With grant money from the National Insti-

tute of Dental and Craniofacial Research, Levy

set out to determine how much fluoride children

consume and how it affects their teeth and

bones. There is no universally accepted optimal

level for daily intake of fluoridethat is, a level

that maximizes protection against tooth decay

while minimizing other risksbut the range

most often cited by researchers is 0.05 to 0.07

milligram of fluoride per kilogram of body

weight per day. In the early 1990s, when the

children in Levys study were infants, he found

that more than a third of them were ingesting

enough fluoridemostly via water-based infant

formula, baby foods and juice drinksto put

them at a high risk of developing mild fluorosis

in their permanent teeth. That fraction dropped

only slightly as their diet changed during their

toddler yearsa critical period for enamel for-

mation in preemergent teeth. Typical fluoride

ingestion stayed high during the toddler years,

in part because toothpaste replaced formula as

a key source. Although both children and adults

are supposed to spit out their toothpaste after

brushing, Levy had found in an earlier study

that toddlers on average actually swallowed

more than half of their toothpaste.

By the time the Iowa children were nine

years old and their permanent front teeth had

emerged, it was obvious that the earlier expo-

sures to fluoride had literally left their mark.

The front teeth of children who had been in the

high-intake group as infants and toddlers were

more than twice as likely to show the telltale

staining of fluorosis than the teeth of children

who had ingested less fluoride when they were

younger. And as their diet broadened, so did

their sources of fluoride. Tests performed in

[AREA OF CONCERN]

p Normal Bone Formation

Scientists have focused on fluorides effects on bone because so much of the chemical is stored there.

Studies have shown that high doses of fluoride can stimulate the proliferation of bone-building osteo-

blast cells, raising fears that the chemical may induce malignant tumors. Fluoride also appears

to alter the crystalline structure of bone, possibly increasing the risk of fractures.

IS FLUORIDE WEAKENING BONE?

Compactbone

Spongybone

PeriosteumMarrow

Existing bone

Bloodvessels

Osteoblasts formingnew bone

Layer of newweak bone

p Effects of Excessive Fluoride

Scientificattitudes

towardfluoridation

may bestarting

to shift in

the countrywhere thepractice

began.

Proliferation ofosteoblasts

Fluorideions

ANDREWS

WIFT



10/37


Levys lab found, for example, that many kinds

of juice drinks and soda pop contain enough

fluoride (generally about 0.6 mg/L) so that

drinking a little more than a liter a day would

put a typical three-year-old at the optimal in-

take level, without counting any other daily

sources.Dozens of food items tested by Levys team

contained even higher concentrations of fluo-

ride: an average of 0.73 mg/L in cranberry-juice

cocktail, 0.71 mg/L in ice pops, 0.99 mg/L in

beef gravy and 2.10 mg/L in canned crabmeat,

for example. In most cases, the fluoride came

from water added during processing, although

higher levels also got into grapes and raisins via

pesticides, into processed chicken products via

ground-up bone, and into tea leaves via absorp-

tion from soil and water.

Levy found that exposure to fluoridated

drinking water was an even more important risk

factor for fluorosis. Iowa children who lived in

communities where the water was fluoridated

were 50 percent more likely to have mild fluoro-

sis on at least two of their eight permanent front

teeth at nine years of age than children living in

nonfluoridated areas of the state (there was a 33

percent prevalence in the former versus 22 per-

cent in the latter). Similar results appeared in

the NRC report, which found that infants and

toddlers in fluoridated communities ingest

about twice as much fluoride as they should.

Furthermore, the committee noted that adults

who drink above-average amounts of water, in-

cluding athletes and laborers, are also exceed-

ing the optimal level for fluoride intake.

But enamel fluorosis, except in the severest

cases, has no health impact beyond lowered

self-esteem: the tooth marks are unattractive

and do not go away (although there are mask-

ing treatments). The much more important

question is whether fluorides effects extend be-

yond altering the biochemistry of tooth enamel

formation. Says longtime fluoride researcher

Pamela DenBesten of the University of Califor-

nia, San Francisco, School of Dentistry: We

certainly can see that fluoride impacts the way

proteins interact with mineralized tissue, so

what effect is it having elsewhere at the cellular

level? Fluoride is very powerful, and it needs to

be treated respectfully.

Fluoride and BoneBone is an obvious place to look for fluorides

fingerprints because so much fluoride is stored

there. What is more, studies of patients with

osteoporosisa bone disease that increases the

risk of fractureshave shown that high doses

of fluoride can stimulate the proliferation of

bone-building osteoblast cells, even in elderly

patients. The exact mechanism is still unknown,

but fluoride appears to achieve this by increas-

ing the concentrations of tyrosine-phosphory-lated proteins, which are involved in biochemi-

cal signaling to osteoblasts. As with tooth

enamel, however, fluoride not only stimulates

bone mineralization, it also appears to alter the

crystalline structure of boneand in this case,

the effects are not merely aesthetic. Although

fluoride may increase bone volume, the strength

of the bone apparently declines. Epidemiologi-

cal studies and tests on lab animals suggest that

high fluoride exposure increases the risk of bone

fracture, especially in vulnerable populations

such as the elderly and diabetics. Although

those studies are sti ll somewhat controversial,

nine of the 12 members of the NRC panel con-

cluded that a lifetime of exposure to drinking

water fluoridated at 4 mg/L or higher does

indeed raise the risk of fracture. The committee

noted that lower fluoridation levels may also

increase the risk, but the evidence is murkier.

As the Iowa children in his study enter ado-

lescence, Levy hopes that analyses of the

strength of their spine, hips and overall skeleton

will point to possible connections between fluo-

ride intake and bone health. He presented some

preliminary data in 2007, finding little differ-

ence in the mineral content of the bones of 11-

year-olds based on how much fluoride they had

ingested as young children. As they go through

adolescence, however, Levy thinks that

trends may emerge.

The even bigger question looming over

the fluoride debate is whether these known

cellular effects in bones and teeth are clues

that fluoride is affecting other organs and

triggering other diseases besides fluorosis.

The biggest current debate is over osteosar-

comathe most common form of bone can-

cer and the sixth most prevalent cancer in

children. Because fluoride stimulates the pro-

duction of osteoblasts, several researchers

have suggested that it might induce malignant

tumors in the expanding cell population. A

1990 study conducted by the U.S. govern-

ments National Toxicology Program found

a positive dose-response relation for osteo-

sarcoma incidence in male rats exposed to

different amounts of fluoride in drinking wa-

ter (all those amounts, as is typical for ani-

SIGNS OF

FLUOROSIS

When young children consume

large amounts of fluoride, thechemical can disrupt the develop-

ment of their permanent teeth.When the teeth emerge, their

enamel may be discolored (top)or, in more severe cases, disfig-

ured (bottom ). Researchers havefound that this condition, called

dental fluorosis, is more commonin communities where the drink-

ing water is fluoridated.

STEVENM.

LEVYUniversityofIowa



11/37


mal studies, were far above the actual expo-

sures found in fluoridated communities). But

other animal studies as well as most epidemio-

logical studies in human populations have been

ambiguous at best.

The latest dustup over fluoride and osteosar-

coma was instigated by a young researchernamed Elise B. Bassin of the Harvard School of

Dental Medicine. Bassin collected information

about fluoride exposures among 103 osteosar-

coma patients and 215 matched control subjects

and concluded that fluoride is a risk factor for

the cancer among boys (the results were ambig-

uous for girls). Bassins report appeared in 2006

in the journal Cancer Causes and Control; in

the same issue, however, her dissertation advis-

er at Harvard, Chester Douglass, wrote a com-

mentary warning readers to be especially cau-

tious in interpreting her findings because, he

said, better data, still unpublished, contradict

them. Antifluoridationists and some envi-

ronmental groups quickly rushed to

Bassins defense, demanding that Har-

vard investigate Douglass, professor

and chair of epidemiology at the den-

tal school, for allegedly misrepresent-

ing Bassins work and for having a con-

flict of interest because he is editor in

chief of a newsletter for dentists funded by

Colgate. The universitys investigation of Doug-

lass, completed in 2006, concluded that there

was no misconduct or conflict of interest.

Clashes over the possible neurological effects

of fluoride have been just as intense. Phyllis

Mullenix, then at the Forsyth Institute in Bos-

ton, set off a firestorm in the early 1990s

when she reported that experiments on

lab rats showed that sodium fluoride

can accumulate in brain tissue and af-

fect animal behavior. Prenatal expo-

sures, she reported, correlated with hy-

peractivity in young rats, especially

males, whereas exposures after birth had

the opposite effect, turning female rats

into what Mullenix later described as

couch potatoes. Although her research

was eventually published in Neurotoxicology

and Teratology, it was attacked by other

scientists who said that her methodolo-

gy was flawed and that she had used un-

realistically high dosages. Since then,

however, a series of epidemiological

studies in China have associated high

fluoride exposures with lower IQ, and

research has also suggested a possible

mechanism: the formation of aluminum fluo-

ride complexessmall inorganic molecules that

mimic the structure of phosphates and thus in-

fluence enzyme activity in the brain. There is

also some evidence that the silicofluorides used

in water fluoridation may enhance the uptake

of lead into the brain.The endocrine system is yet another area

where some evidence exists that fluoride can

have an impact. The NRC committee conclud-

ed that fluoride can subtly alter endocrine func-

tion, especially in the thyroidthe gland that

produces hormones regulating growth and me-

tabolism. Although researchers do not know

how fluoride consumption can influence the

thyroid, the effects appear to be strongly influ-

enced by diet and genetics. Says John Doull,

professor emeritus of pharmacology and toxi-

cology at the University of Kansas Medical Cen-

ter, who chaired the NRC committee: The thy-

roid changes do worry me. There are some

things there that need to be explored.

The Controversy ContinuesThe release of the NRC report has not triggered

a public stampede against fluoridation, nor has

it prompted the EPA to quickly lower its fluoride

limit of 4 mg/L (the agency says it is still study-

ing the issue). Water suppliers who add fluoride

typically keep levels between 0.7 to 1.2 mg/L,

far below the EPA limit. About 200,000 Ameri-

cansand several million people in China,

India, the Middle East, Africa and Southeast

Asiadrink concentrations higher than the lim-

it, but their excess fluoride comes from natural-

ly occurring runoff from fluoride-containing

rocks and soils near water sources.

The report is, however, prompting some re-

searchers to wonder whether even 1 mg/L is too

much in drinking water, in light of the growing

recognition that food, beverages and dental

products are also major sources of fluoride, es-

pecially for young children. The NRC commit-

tee did not formally address the question, but

its analyses suggest that lower water fluorida-

tion levels may pose risks, too. What the com-

mittee found is that weve gone with the status

quo regarding fluoride for many yearsfor too

long, reallyand now we need to take a fresh

look, Doull says. In the scientific community,

people tend to think this is settled. I mean, when

the U.S. surgeon general comes out and says this

is one of the 10 greatest achievements of the

20th century, thats a hard hurdle to get over.

But when we looked at the studies that have

A FLUORIDE DIET

The optimal range for daily intakeof fluoridethe level that maxi-

mizes protection against toothdecay but minimizes other risks

is generally considered to be 0.05to 0.07 milligram for each kilo-

gram of body weight. Consumingfoods and beverages with large

amounts of fluoride can put a dietabove this range. Below are typi-

cal trace levels of fluoride, mea-sured in parts per million (ppm),

found in foods and drinks testedat the University of Iowa College

of Dentistry.

3.73 ppm Brewed black tea2.34 ppm Raisins u2.02 ppm White wine1.09 ppm Apple-

flavoredjuice drink

0.91 ppm Brewedcoffee

0.71 ppmTap water(U.S.-wideaverage)

0.61 ppm Chicken soupbroth0.60 ppm Diet Coke

(U.S.-wideaverage)

0.48 ppm Hot dog0.46 ppm Grapefruit

juice

0.45 ppm Beer u0.45 ppm Baked russet

potatoes

0.35 ppm Cheddar cheese0.33 ppm Flour

tortillas

0.32 ppm Creamed corn(baby food)

0.23 ppm Chocolateice cream u

0.13 ppm Brewedchamomile tea

0.03 ppm Milk (2%) DAVIDROSENBERGGettyImages(hotdog);IMAGESO

URCEPINK/GETTYIMAGES(raisins);JONATHANKITCHENGettyImages

(beer);CSQUAREDSTUDIOS/GETTYIMAGES(icecream)



12/37


been done, we found that many of these ques-

tions are unset tled and we have much less infor-

mation than we should, considering how long

this [fluoridation] has been going on. I think

thats why fluoridation is still being challenged

so many years after it began. In the face of igno-

rance, controversy is rampant.

Some longtime fluoride researchers, however,

remain unimpressed by the evidence of effects

beyond teeth and bones, and they continue to

push for an expansion of water fluoridation in

the U.S. and elsewhere. Their view remains the

official position of the American Dental Asso-

ciation and the U.S. Public Health Service. We

feel there are enough communities out there

with high caries rates to justify additional fluo-

ridation, says Jayanth V. Kumar, director of

oral health surveillance and research at the New

York State Department of Health and a member

of the NRC panel who dissented from some of

its findings. He acknowledges, however, that

the argument for water fluoridation is not as

strong in affluent areas with good nutrition and

dental care. Today it depends on what the car-

ies level is in the community. If the disease is

low, the return on investment [for fluoridation]

may not be all that great.

Opponents of fluoridation, meanwhile, have

been emboldened by the NRC report. What

the committee did was very, very important, be-

cause its the first time a truly balanced panel

has looked at this and raised important ques-

tions, says Paul Connett, a chemistry professor

at St. Lawrence University and the executive di-

rector of the Fluoride Action Network, one of

the most active antifluoridation groups world-

wide. I absolutely believe its a scientific turn-

ing point because now everythings on the table.

Fluoride is the most consumed drug in the U.S.,

and its time we talked about it. g

The risks of fluoride were known long before its benefits. Starting in the first decade of the 20th century, adentist named Frederick McKay traveled the American West investigating reports of what was then knownas Colorado Brown Stain. With a collaborator, G. V. Black, dean of the Northwestern University Dental School,

McKay discovered that children born in Colorado Springs, Colo., had stained teeth, but adults who movedthere did not. They hypothesized that young children whose permanent teeth had not yet erupted or developed

enamel faced the highest risk of developing the stain. McKay, who guessed that the stain was caused by some

unknown compound in the local drinking water, also noticed a curious fact: the mottled teeth were surprisingly

resistant to decay.

The cause remained a mystery until 1930, when McKay went to Arkansas to investigate reports of tooth

staining in Bauxite, a company town owned by the Aluminum Company of America (Alcoa). Worried that alu-

minum might be blamed, Alcoas chief chemist, H. V. Churchill, tested the local water and discovered some-

thing McKay had never suspected: high levels of naturally occurring fluoride. McKay quickly tested other sus-

pect water supplies and found that wherever fluoride levels were hightypically 2.5 milligrams per liter or

higherColorado Brown Stain was prevalent. A new disease entered the

lexicon: fluorosis.

Spurred by Churchills and McKays discoveries, a researcher named

Henry Trendley Dean, head of the dental hygiene unit at the National

Institute of Health (which later changed its name to the National Insti-

tutes of Health) , tried to determine how much fluoride was enough to

trigger fluorosis. By the late 1930s he had concluded that levels below

1 mg/L would pose little risk. Dean remembered that McKay had

found that fluorosed teeth were resistant to decay, and so he began

pushing for a citywide test of a revolutionary idea: deliberately add-

ing fluoride to water at levels that would deter cavities without trig-

gering fluorosis. He got his wish in 1945 in Grand Rapids, Mich.,

and Dean went on to become fluoridations leading advocate as the

first director of the newly formed National Institute of Dental Re-

search from 1948 until his retirement in 1953. D.F.

tCOLORADO DENTIST Frederick McKay,

whose investigations led to the discoveryof fluorides effects on teeth.

[BACKGROUND]

FLUORIDE HISTORY

MORE TOEXPLORE

Patterns of Fluoride Intake fromBirth to 36 Months. Steven M.Levy, John J. Warren, Charles S.

Davis, H. Lester Kirchner, Michael J.Kanellis and James S. Wefel inJour-nal of Public Health Dentistry, Vol. 61,No. 2, pages 7077; June 2001.

Patterns of Fluoride Intake from36 to 72 Months of Age. Steven M.Levy, John J. Warren and BarbaraBroffitt inJournal of Public HealthDentistry, Vol. 63, No. 4, pages 211220; December 2003.

Timing of Fluoride Intake in Rela-

tion to Development of Fluorosison Maxillary Central Incisors.

Liang Hong, Steven M. Levy,Barbara Broffitt, John J. Warren,Michael J. Kanellis, James S. Wefeland Deborah V. Dawson in Commu-nity Dentistry and Oral Epidemiology,Vol. 34, No. 4, pages 299309 ;August 2006.

Age-Specific Fluoride Exposure in

Drinking Water and Osteosarco-ma. Elise B. Bassin, David Wypij,Roger B. Davis and Murray A.Mittleman in Cancer Causes and Con-trol, Vol. 17, No. 4, pages 421428;May 2006.

Caution Needed in Fluoride andOsteosarcoma Study. Chester W.Douglass and Kaumudi Joshipura inCancer Causes and Control, Vol. 17,No. 4, pages 481482; May 2006.

Fluoride in Drinking Water:

A Scientific Review of EPAs

Standards. National Academyof Sciences, 2006. Available atwww.nap.edu/catalog.php?record_id=11571BE

TTMANN/CORBIS



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STATEMENT BY DR. HARDY LIMEBACK

by Dr. Hardy Limeback PhD, DDS

Associate Professor and Head, Preventive Dentistry

University of Toronto

I am the Head of Preventive Dentistry at the University of Toronto in Toronto Canada , a

professor with a PhD in Biochemistry and a practicing dentist who has done years of funded

research in tooth formation, bone and fluoride. I was one of the 12 scientists who served on the

National Academy of Sciences panel that issued the 2006 report, Fluoride in Drinking Water: A

Scientific Review of the EPAs Standards.

I would like to outline my arguments that fluoridation is an ineffective and harmful public health

policy.

1. Fluoridation is no longer effective .

Fluoride in water has the effect of delaying tooth eruption and, therefore, simply delays dental

decay (Komarek et al, 2005, Biostatistics 6:145-55). The studies that water fluoridation work are

over 25 years old and were carried out before the widespread use offluoridated toothpaste .

There are numerous modern studies to show that there no longer is a difference in dental

decay rates between fluoridated and non-fluoridated areas, the most recent one in Australia

(Armfield & Spencer, 2004 Community Dental Oral Epidemiology. 32:283-96). Recent water

fluoridation cessation studies show that dental fluorosis (a mottling of the enamel caused by

fluoride) declines but there is no corresponding increase in dental decay (e.g. Maupome et al

2001, Community Dental Oral Epidemiology 29: 37-47).

Public health services will claim there is still a dental decay crisis. With the national average inEurope of only two decayed teeth per child (World Health Organization data), down from more

than 15 decayed teeth in the 1940s and 1950s before fluoridated toothpaste, as much as half of all

children grow up not having a single filling. This remarkable success has been achieved in most

European countries without fluoridation. The crisis of dental decay often mentioned is the

result, to a major extent, of sugar abuse, especially soda pop. A 2005 report by Jacobsen of the

Center for Science in the Public Interest said that U.S. children consume 40 to 44 percent of their

daily refined sugar in the form of soft drinks. Since most soft drinks are themselves fluoridated,

the small amount of fluoride is obviously not helping.

The families of these children with rampant dental decay need professional assistance. Are they

getting it? Children who grow up in low-income families make poor dietary choices, and cannot

afford dental care. Untreated dental decay and lack of professional intervention result in moredental decay. The York review was unable to show that fluoridation benefited poor people.

Similarly, early dental decay in nursing infants (baby bottle syndrome) cannot be prevented with

water fluoridation. The majority of dentists in the U.S. do not accept Medicaid patients because

they lose money treating these patients. I would think the same is true for dentists in Europe .

Dentists support fluoridation programs because it absolves them of their responsibility to provide


15/37

assistance to those who cannot afford dental treatment. Even cities where water fluoridation has

been in effect for years are reporting similar dental crises.

Public health officials responsible for community programs are misleading the public by stating

that ingesting fluoride makes the teeth stronger. Fluoride is not an essential nutrient. It does notmake developing teeth better prepared to resist dental decay before they erupt into the oral

environment. The small benefit that fluoridated water might still have on teeth (in the absence of

fluoridated toothpaste use) is the result of topical exposure while the teeth are rebuilding from

acid challenges brought on by daily sugar and starch exposure (Limeback 1999, Community

Dental Oral Epidemiology 27: 62-71), and this has now been recognized by the Centers for

Disease Control.

2. Fluoridation is the main cause of dental fluorosis .

Fluoride doses by the end user cant be controlled when only one concentration of fluoride (1

parts per million) is available in the drinking water. Babies and toddlers get too much fluoride

when tap water is used to make formula (Brothwell & Limeback, 2003 Journal of HumanLactation 19: 386-90). Since the majority of daily fluoride comes from the drinking water in

fluoridated areas, the risk for dental fluorosis greatly increases (National Academy of Sciences:

Toxicological Risk of Fluoride in Drinking Water, 2006). The American Dental Association and

the Dental Forum in Ireland has admitted that fluoridated tap water should not be used to

reconstitute infant formula.

We have tripled our exposure to fluoride since fluoridation was conceived in the 1940s. This has

lead to every third child with dental fluorosis (CDC, 2005). Fluorosis is not just a cosmetic

effect. The more severe forms are associated with an increase in dental decay (NAS:

Toxicological Risk of Fluoride in Drinking Water, 2006) and the psychological impact on

children is a negative one. Most children with moderate and severe dental fluorosis seek

extensive restorative work costing thousands of dollars. Dental fluorosis can be reduced byturning off the fluoridation taps without affecting dental decay rates (Burt et al 2000 Journal of

Dental Research 79(2):761-9).

3. Chemicals that are used in fluoridation have not been tested for safety .

All the animal cancer studies were done on pharmaceutical-grade sodium fluoride. There is more

than enough evidence to show that even this fluoride has the potential to promote cancer. Some

communities use sodium fluoride in their drinking water, but even that chemical is not the same

fluoride added to toothpaste. Most cities instead use hydrofluorosilicic acid (or its salt). H2SiF6

is concentrated directly from the smokestack scrubbers during the production of phosphate

fertilizer, shipped to water treatment plants and trickled directly into the drinking water. It is

industrial grade fluoride contaminated with trace amounts of heavy metals such as lead, arsenic

and radium, which are harmful to humans at the levels that are being added to fluoridate the

drinking water. In addition, using hydrofluorosilicic acid instead of industrial grade sodium

fluoride has an added risk of increasing lead accumulation in children (Masters et al 2000,

Neurotoxicology. 21(6): 1091- 1099), probably from the lead found in the pipes of old houses.


16/37

This could not be ruled out by the CDC in their recent study (Macek et al 2006, Environmental

Health Perspectives 114:130-134).

4. There are serious health risks from water fluoridation .

Cancer: Osteosarcoma (bone cancer) has recently been identified as a risk in young boys in a

recently published Harvard study (Bassin, Cancer Causes and Control, 2006). The author of this

study, Dr. Elise Bassin, acknowledges that perhaps it is the use of these untested and

contaminated fluorosilicates mentioned above that caused the over 500% increase risk of bone

cancer.

Bone fracture: Drinking on average 1 liter/day of naturally fluoridated water at 4 parts per

million increases your risk for bone pain and bone fractures (National Academy of Sciences:

Toxicological Risk of Fluoride in Drinking Water, 2006). Since fluoride accumulates in bone, the

same risk occurs in people who drink 4 liters/day of artificially fluoridated water at 1 part per

million, or in people with renal disease. Additionally, Brits are known for their tea drinking and

since tea itself contains fluoride, using fluoridated tap water puts many heavy tea drinkersdangerously close to threshold for bone fracture. Fluoridation studies have never properly shown

that fluoride is safe in individuals who cannot control their dose, or in patients who retain too

much fluoride.

Adverse thyroid function: The recent National Academy of Sciences report (NAS: Toxicological

Risk of Fluoride in Drinking Water, 2006) outlines in great detail the detrimental effect that

fluoride has on the endocrine system, especially the thyroid. Fluoridation should be halted on the

basis that endocrine function in the U.S. has never been studied in relation to total fluoride

intake.

Adverse neurological effects: In addition to the added accumulation of lead (a known

neurotoxin) in children living in fluoridated cities, fluoride itself is a known neurotoxin. We areonly now starting to understand how fluoride affects the brain. Several recent studies suggest that

fluoride in drinking water lowers IQ (NAS, 2006), we need to study this more in depth.

In my opinion, the evidence that fluoridation is more harmful than beneficial is now

overwhelming and policy makers who avoid thoroughly reviewing recent data before introducing

new fluoridation schemes do so at risk of future litigation.


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Fluoridation: Time to reevaluate 19 October 2007


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Vol. 60,No. 3, Summer 2000 131R E V I E W & C O M M E N T A R Y

Fluoride Intake and Prevalence of Dental Fluorosis:Trends in Fluoride Intake with Special Attention to InfantsSamuel J. Fomon, MD; Jan Ekstrand, DDS, PhD; Ekhard E. Ziegler, MDAbstract

Background: Although the predominant beneficial effect of fluoride occurslocally in the mouth, the adverse effect, dental fluorosis, occurs by the systemicroute. The caries attack rate n industrializedcountries, ncluding the Unitedstatesand Canada, has decreased dramatically over the past 40 years. However, theprevalence of dental fluorosis in the United States has increased during the last30 years both in communities with fluoridated water and in communities withnonfluoridated water. Dental fluorosis is closely associated with fluoride intakeduring the period of tooth development. Methods: We reviewed the majorchanges in infant feeding practices that have occurred since 1930 and thechanges in fluoride ntakes by infants and young children associated with changesin feeding practices. Results and Conclusions: Based on this review, weconclude that fluoride intakes of infants and children have shown a rather steadyincrease since 1930, are likely to continue to ncrease, and will be associated withfurther increase in the prevalence of enamel fluorosis unless intervention meas-ures are nstituted.Recommendations:We believe the most important measuresthat should be undertaken are ( I ) use, when feasible, of water low in fluoride fordilution of infant formulas; (2) adult supervision of toothbrushing by childrenyounger than 5 years of age; and (3) changes in recommendations for admini-stration of fluoride supplementsso that such supplements are not given to infantsand more stringent criteria are applied for administration to children.Key Words: dental fluorosis, fluoride supplements, fluoridated dentifrices, ormulafluoride.[J Public Health Dent 2000;60(3): 131-91

Current evidence suggests that thepredominant beneficial effectsof fluo-ride occur locally at the tooth surface,and that systemic (preeruptive)effectsare of much less importance (1-5).Be-cause fluoride intake at intervalsthroughout the day is an importantfactor in limiting the prevalence andseverity of dental caries in eruptedteeth, fluorida tion of communitydrinking water has been and contin-ues to be a useful public health meas-ure. In addition, the widespread use offluoridated dentifrices has providedeffective topical application of fluorideto erupted teeth.Although the predominant benefi-cial effect of fluoride occurs locally inthe mouth, the adverse effect, dental

fluorosis, occurs by the systemic route.From the beginning of tooth formationuntil tooth eruption, fluoride appearsable to exert an adverse effect on den-tal enamel at a number of develop-mental stages (6,7).Of the severalmechanisms proposed for the adverseeffect on tooth development, the mostlikely is that fluoride has an effect oncell function, either through interac-tions with the developing ameloblastsor the intracellular matrix (8). Dentalfluorosis is characterized by an in-creasing porosity (hypomineraliza-tion) of the subsurface enamel, caus-ing the enamel to appear opaque. Theclinical features include changes rang-ing from barely discernible fine whitelines running across the teeth to en-

tirely chalky white teeth (8). In ad-vanced stages, the enamel may be-come so porous that the outer layersbreak down and the exposed poroussubsurface becomes discolored.The caries attack rate in industrial-ized countries, including the UnitedStates and Canada, has decreased dra-matically over the past 40 years (9).Onthe other hand, based on changes inthe earlier community fluorosis indexand in the more recent index of Thyl-strup and Fejerskov (lo), the preva-lence of dental fluorosis in the UnitedStates has increased during the last 30years, both in communities withfluoridated water and in communitieswith nonfluoridated water (1,11-18).Because dental fluorosis is closelyassociated with fluoride intake duringthe period of tooth development (19),we reasoned that a review of trends influoride intake over the past 70yearswould be useful in predicting futuretrends in dental fluorosis. Thus, thepurpose of th is communication is toreview trends since 1930 in fluorideintakes by infants and young children.We shall put particular emphasis onreview of data on fluoride intake byinfants because major changes in in-fant feeding practices over the past 70years have been associated with age-related changes in fluoride intake, andwe believe that these changes have notbeen generally recognized.General Considerations

Because the beneficial action of fluo-ride in caries prevention is a local ef-fect within the mouth, the exposure tofluoride throughout the life span is amajor factor in prevention of dentalcaries, and, i f a choice is to be madebetween decreasing incidence of den-tal caries and increasing incidence of

Send correspondence and reprint requests toDr.Fomon, Departmentof Pediatrics, University of Iowa Hospitals and Clinics, 200 Hawkins Drive,Iowa City, IA 52242-1083.E-mail: [email protected]. kstrand is affiliated with the Department of Basic Oral Sciences, School of Dentisw,Karolinska Institute, Huddinge, Sweden. Dr. Ziegleriswith the Department of Pediatrics, University of Iowa. The presentation is an updated andexpanded version of a paper presented at the Dietary Fluoride Supplement Workshop, Chicago, IL,Jan 31-Feb 1,1994. Manuscript received:9/14/99; returned to authors for revision: 4/19/00; accepted forpublication:6/5/00.


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Comparison of hydrofluorosilicic acid and pharmaceutical

sodium fluoride as fluoridating agentsA costbenefit

analysis

J. William Hirzy a,*, Robert J. Cartonb, Christina D. Bonanni a, Carly M. Montaneroa,Michael F. Nagle a

aAmerican University, Department of Chemistry, 4400 Massachusetts Ave., N.W., Washington, DC,. USAb4 Glenwood Terrace, Averill Park, NY, USA

e nv i ro n me nt a l s ci e nc e & p ol i cy x x x ( 2 01 3 ) x x x x xx

a r t i c l e i n f o

Article history:

Received 30 March 2012

Received in revised form

14 January 2013

Accepted 15 January 2013

Keywords:

Fluoride

Arsenic

CancerFluoridation

Costbenefit analysis

a b s t r a c t

Water fluoridation programs in theUnitedStates andother countries which have them use

either sodium fluoride (NaF), hydrofluorosilicic acid (HFSA) or the sodium salt of that acid

(NaSF), all technical grade chemicals to adjust the fluoride level in drinking water to about

0.71 mg/L. In this paperwe estimate the comparative overall cost for U.S. society between

using cheaper industrial grade HFSA as the principal fluoridating agent versus using more

costly pharmaceutical grade (U.S. Pharmacopeia USP) NaF. USP NaF is used in toothpaste.

HFSA, a liquid, contains significant amounts of arsenic (As). HFSA and NaSF have been

shown to leach lead (Pb)fromwater delivery plumbing, whileNaF has beenshown not to do

so. The U.S. Environmental Protection Agencys (EPA) health-based drinking water stan-

dards for As and Pb are zero. Our focus was on comparing the social costs associatedwith

the difference innumbers of cancercasesarising fromAsduringuse ofHFSA asfluoridating

agent versus substitution of USP grade NaF. We calculated the amount of As delivered tofluoridatedwatersystemsusingeachagent,andused EPAUnitRisk valuesforAs toestimate

the number of lung and bladder cancer cases associated with each. Weused cost of cancer

cases published by EPA to estimate cost of treating lung and bladder cancer cases. Com-

mercial prices ofHFSAandUSP NaF were used to compare costs of using each to fluoridate.

We then compared the total cost to our society for the use of HFSA versus USP NaF as

fluoridatingagent. TheU.S. could save $1 billion to more than $5 billion/year by using USP

NaF inplaceofHFSAwhile simultaneously mitigating thepain andsufferingof citizens that

result fromuse of the technical grade fluoridating agents. Other countries, such as Ireland,

NewZealand, CanadaandAustraliathat usetechnicalgradefluoridatingagentsmay realize

similar benefits by making this change. Policy makers would have to confront the uneven

distribution of costs and benefits across societies if this change were made.

# 2013 Elsevier Ltd. All rights reserved.

* Correspondingauthor at: Department of Chemistry, American University, 4400Massachusetts Ave., N.W., Washington, DC 20016, USA.Tel.: +1 202 885 1780; fax: +001 202 8851752.E-mail addresses: [email protected], [email protected] (J.W. Hirzy).

ENVSCI-1173; No. of Pages 6

Please cite this article in press as: Hirzy, J.W., et al., Comparison of hydrofluorosilicic acid and pharmaceutical sodium fluoride as fluoridating

agentsA costbenefit analysis. Environ. Sci. Policy (2013), http://dx.doi.org/10.1016/j.envsci.2013.01.007

Available online at www.sciencedirect.com

journal homepage: www.elsevier.com/locate/envsci

1462-9011/$ see front matter # 2013 Elsevier Ltd. All rights reserved.http://dx.doi.org/10.1016/j.envsci.2013.01.007


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1362 VOLUME 120 |NUMBER 10 | October 2012 t Environmental Health Perspectives

Review

A recent report from the National ResearchCouncil (NRC 2006) concluded that adverse

effects of high fluoride concentrations indrinking water may be of concern and thatadditional research is warranted. Fluoride maycause neurotoxicity in laboratory animals,including effects on learning and memory(Chioca et al. 2008; Mullenix et al. 1995). Arecent experimental study where the rat hip-pocampal neurons were incubated with vari-ous concentrations (20 mg/L, 40 mg/L, and80 mg/L) of sodium fluoride in vitro showedthat fluoride neurotoxicity may target hip-pocampal neurons (Zhang M et al. 2008).Although acute fluoride poisoning may beneurotoxic to adults, most of the epidemio-logical information available on associationswith childrens neurodevelopment is fromChina, where fluoride generally occurs indrinking water as a natural contaminant, andthe concentration depends on local geologi-cal conditions. In many rural communitiesin China, populations with high exposure tofluoride in local drinking-water sources mayreside in close proximity to populations with-out high exposure (NRC 2006).

Opportunities for epidemiological stud-ies depend on the existence of comparablepopulation groups exposed to different levels

of fluoride from drinking water. Such cir-cumstances are difficult to find in many

industrialized countries, because fluoride con-centrations in community water are usuallyno higher than 1 mg/L, even when fluorideis added to water supplies as a public healthmeasure to reduce tooth decay. Multiple epi-demiological studies of developmental fluo-ride neurotoxicity were conducted in Chinabecause of the high fluoride concentrationsthat are substantially above 1 mg/L in wellwater in many rural communities, althoughmicrobiologically safe water has been acces-sible to many rural households as a result ofthe recent 5-year plan (20012005) by theChinese government. It is projected that allrural residents will have access to safe publicdrinking water by 2020 (World Bank 2006).However, results of the published studies havenot been widely disseminated. Four studiespublished in English (Li XS et al. 1995; Luet al. 2000; Xiang et al. 2003; Zhao et al.1996) were cited in a recent report from theNRC (2006), whereas the World HealthOrganization (2002) has considered only two(Li XS et al. 1995; Zhao et al. 1996) in itsmost recent monograph on fluoride.

Fluoride readily crosses the placenta(Agency for Toxic Substances and Disease

Registry 2003). Fluoride exposure to the devel-oping brain, which is much more susceptibleto injury caused by toxicants than is the maturebrain, may possibly lead to permanent damage(Grandjean and Landrigan 2006). In responseto the recommendation of the NRC (2006),the U.S. Department of Health and HumanServices (DHHS) and the U.S. EPA recentlyannounced that DHHS is proposing to changethe recommended level of fluoride in drinkingwater to 0.7 mg/L from the currently recom-mended range of 0.71.2 mg/L, and the U.S.EPA is reviewing the maximum amount offluoride allowed in drinking water, which cur-rently is set at 4.0 mg/L (U.S. EPA 2011).

To summarize the available literature,we performed a systematic review and meta-analysis of published studies on increasedfluoride exposure in drinking water associatedwith neurodevelopmental delays. We specifi-cally targeted studies carried out in ruralChina that have not been widely disseminated,thus complementing the studies that havebeen included in previous reviews and riskassessment reports.

Methods

Search strategy. We sea rched MEDLINE(National Library of Medicine, Bethesda, MD,USA; http://www.ncbi.nlm.nih.gov/pubmed),

Embase (Elsevier B.V., Amsterdam, theNetherlands; http://www.embase.com), WaterResources Abstracts (Proquest, Ann Arbor,MI, USA; http://www.csa.com/factsheets/water-resources-set-c .php), and TOXNET(Toxicology Data Network; National Libraryof Medicine, Bethesda, MD, USA; http://tox-net.nlm.nih.gov) databases to identify studiesof drinking-water fluoride and neurodevel-opmental outcomes in children. In addition,we searched the China National KnowledgeInfrastructure (CNKI; Beijing, China; http://www.cnki .net) database to identi fy stud-ies published in Chinese journals only. Key

Address correspondence to A.L. Choi, Department

of Environmental Health, Harvard School of PublicHealth, Landmark Center 3E, 401 Park Dr., Boston,MA 02215 USA. Telephone: (617) 384-8646. Fax:(617) 384-8994. E-mail: [email protected]

Supplemental Material is available online (http://dx.doi.org/10.1289/ehp.1104912).We thank V. Malik, Harvard School of Public Health,

for the helpful advice on the meta-analysis methods.is study was supported by internal institutional

funds.e authors declare they have no actual or potential

competing financial interests.Received 30 December 2011; accepted 20 July 2012.

Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis

Anna L. Choi,1 Guifan Sun,2Ying Zhang,3and Philippe Grandjean1,4

1Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; 2School of Public Health, ChinaMedical University, Shenyang, China; 3School of Stomatology, China Medical University, Shenyang, China; 4Institute of Public Health,University of Southern Denmark, Odense, Denmark

BACKGROUND: Although fluoride may cause neurotoxicity in animal models and acute fluoridepoisoning causes neurotoxicity in adults, very little is known of its effects on childrens neuro-development.

OBJECTIVE: We performed a systematic review and meta-analysis of published studies to investigatethe effects of increased fluoride exposure and delayed neurobehavioral development.

METHODS: We searched the MEDLINE, EMBASE, Water Resources Abstracts, and TOXNETdatabases through 2011 for eligible studies. We also searched the China National KnowledgeInfrastructure (CNKI) database, because many studies on fluoride neurotoxicity have been pub-lished in Chinese journals only. In total, we identified 27 eligible epidemiological studies with highand reference exposures, end points of IQ scores, or related cognitive function measures with meansand variances for the two exposure groups. Using random-effects models, we estimated the stan-dardized mean difference between exposed and reference groups across all studies. We conductedsensitivity analyses restricted to studies using the same outcome assessment and having drinking-

water fluoride as the only exposure. We performed the Cochran test for heterogeneity between stud-ies, Beggs funnel plot, and Egger test to assess publication bias, and conducted meta-regressions to

explore sources of variation in mean differences among the studies.RESULTS:e standardized weighted mean difference in IQ score between exposed and referencepopulations was 0.45 (95% confidence interval: 0.56, 0.35) using a random-effects model.us, children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas. Subgroup and sensitivity analyses also indicated inverse associations, although thesubstantial heterogeneity did not appear to decrease.

CONCLUSIONS:e results support the possibility of an adverse effect of high fluoride exposure onchildrens neurodevelopment. Future research should include detailed individual-level informationon prenatal exposure, neurobehavioral performance, and covariates for adjustment.

KEYWORDS: fluoride, intelligence, neurotoxicity. Environ Health Perspect120:13621368(2012). http://dx.doi.org/10.1289/ehp.1104912[Online 20 July 2012]


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Confirmation of and explanations for elevated blood lead andother disorders in children exposed to water disinfection and

fluoridation chemicals

Myron J. Coplan a,*, Steven C. Patch b, Roger D. Masters c, Marcia S. Bachman a

aIntellequity Technology Services Natick, Massachusetts, United Statesb Environmental Quality Institute, University of North Carolina in Asheville, United States

cDartmouth College Institute for Nuroscience and Society, United States

Received 23 February 2006; accepted 12 February 2007

Available online 1 March 2007

Abstract

Silicofluorides (SiFs), fluosilicic acid (FSA) and sodium fluosilicate (NaFSA), are used to fluoridate over 90% of US fluoridated municipal

water supplies. Living in communities with silicofluoride treated water (SiFW) is associated with two neurotoxic effects: (1) Prevalence of children

with elevated blood lead (PbB > 10 mg/dL) is about double that in non-fluoridated communities (Risk Ratio 2, x2 p < 0.01). SiFW is associated

with serious corrosion of lead-bearing brass plumbing, producing elevated water lead (PbW) at the faucet. New data refute the long-prevailing

belief that PbW contributes little to childrens blood lead (PbB), it is likely to contribute 50% or more. (2) SiFW has been shown to interfere with

cholinergic function. Unlike the fully ionized state of fluoride (F-) in water treated with sodium fluoride (NaFW), the SiF anion, [SiF6]2- in SiFW

releases F- in a complicated dissociation process. Small amounts of incompletely dissociated [SiF6]2- or low molecular weight (LMW) silicic acid

(SA) oligomers may remain in SiFW. A German PhD study found that SiFW is a more powerful inhibitor of acetylcholinesterase (AChE) than

NaFW. It is proposed here that SiFW induces protein mis-folding via a mechanism that would affect polypeptides in general, and explain dental

fluorosis, a tooth enamel defect that is not merely cosmetic but a canary in the mine foretelling other adverse, albeit subtle, health and

behavioral effects. Efforts to refute evidenceof such effectsare analyzed and rebutted. In 1999 and 2000, seniorEPA personnel admitted they knew

of no health effects studies of SiFs. In 2002 SiFs were nominated for NTP animal testing. In 2006 an NRC Fluoride Study Committee

recommended such studies. It is not known at this writing whether any had begun.

# 2007 Elsevier Inc. All rights reserved.

Keywords: Elevated blood lead; Silicofluoride; Fluosilicate; Brass corrosion; Enzyme inhibition; Fluorosis

1. Introduction

Chronic ingestion of water bearing 1 ppm of fluoride ion

(F) from NaF was thought harmless to humans when

municipal water fluoridation began in 1945. NaFSA was

substituted in 1947 and endorsed in 1950 by the US Public

Health Service without prior animal testing because rats grew

just as fast, their teeth got as much F as from NaF, and a

community could save 4 cents per year per resident (McClure,

1950).

FSA (H2SiF6) and NaFSA, its sodium salt (Na2SiF6), share

the [SiF6]2 anion, a fluoride complex herein called silico-

fluoride (SiF) which dissociates in water, releasing F. The

dissociation was predicted to be virtually complete at 1 ppm

of F so that SiFW would be just like NaF treated water

(NaFW). Today, 92% of US fluoridated drinking water is SiFW

(CDC, 1993). Senior EPA personnel have found no evidence

SiFW was ever tested for adverse health effects (Fox, 1999;

Thurnau, 2000). In 2002, SiFs were nominated for animal

tests (NTP, 2002) that had not begun as of July 2006.

The NRC report, Fluoride in Drinking Water. . .A

Scientific Review of EPAs Standards (NRC, 2006) empha-

sizes the importance of such testing with questions about

NeuroToxicology 28 (2007) 10321042

* Corresponding author. Tel.: +1 508 653 6147; fax: +1 508 655 3677.

E-mail addresses: [email protected] (M.J. Coplan),

[email protected] (S.C. Patch), [email protected]

(R.D. Masters), [email protected] (M.S. Bachman).

0161-813X/$ see front matter # 2007 Elsevier Inc. All rights reserved.

doi:10.1016/j.neuro.2007.02.012


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Community Dent Oral Epidemiol 2000; 28: 3829 Copyright C Munksgaard 2000Printed in Denmark . All rights reserved

ISSN 0301-5661

W. Knzel1, T. Fischer1, R. Lorenz2 and

S. Brhmann2

Decline of caries prevalence after 1Dental School of Erfurt, Department ofPreventive Dentistry, Friedrich-Schiller-University of Jena, 2Public Health Services ofthe cessation ofwater fluoridation Spremberg and Zittau, Germany

in the former East GermanyKnzel W, Fischer T, Lorenz R, Brhmann S: Decline of caries prevalence afterthe cessation of water fluoridation in the former East Germany. Community DentOral Epidemiol 2000; 28: 3829. C Munksgaard, 2000

Abstract In contrast to the anticipated increase in dental caries following thecessation of water fluoridation in the cities Chemnitz (formerly Karl-Marx-Stadt)

and Plauen, a significant fall in caries prevalence was observed. This trend corre-sponded to the national caries decline and appeared to be a new population-widephenomenon. Additional surveys (N1017) carried out in the formerly-fluori-dated towns of Spremberg (N9042) and Zittau (N6232) were carried out inorder to support this unexpected epidemiological finding. Pupils from thesetowns, aged 8/9-, 12/13- and 15/16-years, have been examined repeatedly overthe last 20 years using standardised caries-methodological procedures. While thedata provided additional support for the established fact of a caries reduction

brought about by the fluoridation of drinking water (48 % on average), it hasalso provided further support for the contention that caries prevalence may contin-ue to fall after the reduction of fluoride concentration in the water supply fromabout 1 ppm to below 0.2 ppm F. Caries levels for the 12-year-olds of both townssignificantly decreased during the years 199396, following the cessation of waterfluoridation. In Spremberg, DMFT fell from 2.36 to 1.45 (38.5 %) and in Zittau from2.47 to 1.96 (20.6%). These findings have therefore supported the previously ob- Key words: caries prevalence; cessation;

children; East Germany; water fluoridationserved change in the caries trend of Chemnitz and Plauen. The mean of 1.81 DMFTfor the 12-year-olds, computed from data of the four towns, is the lowest ob- Walter Knzel, Dental School of Erfurt and

WHO Collaborating Centre for theserved in East Germany during the past 40 years. The causes for the changed cariesPrevention of Oral Diseases, Nordhuser Str.trend were seen on the one hand in improvements in attitudes towards oral78, D 99089 Erfurt, Germany

health behaviour and, on the other hand, to the broader availabilty and application Tel: 49 361 741 1209of preventive measures (F-salt, F-toothpastes, fissure sealants etc.). There is, how- Fax: 49 361 741 1109

e-mail: Simionoff/zmkh.ef.uni-jena.deever, still no definitive explanation for the current pattern and further analysis offuture caries trends in the formerly fluoridated towns would therefore seem to Submitted 5 January 1999; accepted

be necessary. 7 February 2000

Long-lasting discontinuities or a final cessation of

water fluoridation have, hitherto, usually resultedin a caries increase in the juvenile population (1, 2,

3). In contrast to this repeated finding (4, 5, 6), it

emerged that in Chemnitz (formerly Karl-Marx-

Stadt), caries prevalence actually continued todecrease (7), the DMFT-index falling significantly

between 1991 and 1995, from 2.5 to 1.9. A similar

statistical trend was observed in the F-poor controltown Plauen, where water fluoridation had ceased

382

in 198485 due to a necessary reconstruction of the

water supply system. By 1995, the relatively highDMFT of 3.5 for 12-year-olds seen in 1983 had de-

creased to 2.0.

This unexpected trend, shown for the first time

after cessation of water fluoridation (CWF), oc-curred at a time when there was a population-wide

decline in dental caries. This caries decline, which

became evident in the highly industrialised coun-tries of the western hemisphere at the end of the


28/37

7/16/13 4:10 PMCaries prevalence after cessation of wate... [Caries Res. 2000 Jan-Feb] - PubMed - NCBI

Page 1 of http://www.ncbi.nlm.nih.gov/pubmed/10601780

Caries Res. 2000 Jan-Feb;34(1):20-5.

Caries prevalence after cessation of water fluoridation in La Salud, Cuba.

Knzel W, Fischer T.

Department of Preventive Dentistry, Dental School of Erfurt, Friedrich Schiller University of Jena, Germany.

Abstract

In the past, caries has usually increased after cessation of water fluoridation. More recently an

opposite trend could be observed: DMFT remaining stable or even decreasing further. The aim of the

present study conducted in La Salud (Province of Habana) in March 1997 was to analyse the current

caries trend under the special climatic and nutritional conditions of the subtropical sugar island Cuba,following the cessation, in 1990, of water fluoridation (0.8 ppm F). Diagnostic evaluations were carried

out using the same methods as in 1973 and 1982. Boys and girls aged 6-13 years (N = 414), lifelong

residents in La Salud, were examined. Between 1973 and 1982 the mean DMFT had decreased by

71.4%, the mean DMFS by 73. 3% and the percentage of caries-free children had increased from 26.

3 to 61.6%. In 1997, following the cessation of drinking water fluoridation, in contrast to an expected

rise in caries prevalence, DMFT and DMFS values remained at a low level for the 6- to 9-year-olds

and appeared to decrease for the 10/11-year-olds (from 1. 1 to 0.8) and DMFS (from 1.5 to 1.2). In

the 12/13-year-olds, there was a significant decrease (DMFT from 2.1 to 1.1; DMFS from 3.1 to 1. 5),

while the percentage of caries-free children of this age group had increased from 4.8 (1973) and 33.3

(1982) up to 55.2%. A possible explanation for this unexpected finding and for the good oral health

status of the children in La Salud is the effect of the school mouthrinsing programme, which has

involved fortnightly mouthrinses with 0.2% NaF solutions (i.e. 15 times/year) since 1990.

PMID: 10601780 [PubMed - indexed for MEDLINE]

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