fluoride for caries control

8/10/2019 Fluoride for Caries Control

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FLUORIDE FOR CARIES CONTROL

It has been now over 50 years since one of the most significant

advances in dental health care took place. During 1945, Grand Rapids,

Michigan, Newburg, New York, and Branford, Ontario became the first

cities in the world to have sodium fluoride added to their drinking water.

Today water fluoridation is an accepted fact of life in most communities

in this country and in many foreign countries. Water fluoridation has

been a remarkable public health success story in the control of dental

caries.

TOOTH DECAY

Tooth decay is, by far, the most prevalent and costly of oral health

problems among all age groups. It is also the principal cause of tooth

loss from early childhood through middle age, when tooth loss from

periodontal disease is also a major concern. However, caries continues

to be problematic for middle-aged and older adults, particularly root

caries. In addition to its effects in the mouth, dental caries may affect

general well-being by interfering with an individuals ability to eat certain

foods and by impacting an individuals emotional and social well-being

by causing pain and discomfort. Tooth decay, particularly in the frontteeth, can also affect an individuals self-esteem by detracting from the

persons appearance.

Despite a decrease in the overall caries experience among U.S. school

children over the past two decades, tooth decay is still a significant oral

health problem. According to the 1986-87 National Caries Prevalence

Survey, although 50% of U.S. school aged children had not experienced

decay in their permanent teeth, by the age of 17, only 16% of those

surveyed were entirely free of cavities. These data show that nearly allchildren are affected by caries by the time they graduate from high

school.

Because dental caries is so common, it often tends to be regarded as an

inevitable part of life. Caries data from the 1985-1986 National Survey of

Adult Dental Health revealed that, of the 104 million adults represented

by the report, adults of all ages had an average of 23 decayed and filled

tooth surfaces. Forty-nine percent of the employed population over 18

years of age had at least one tooth extracted and in the seniorpopulation, (65 and older), 41% were missing all of their teeth. Tooth


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decay is one of the principal reasons for dental extractions and the large

proportion of people in the community who no longer have any natural

teeth is a striking indication of its impact.

The consequences of dental disease are also reflected in the cost of itstreatment. The nations dental health bill in 1992 was 38.7 billion dollars.

Clearly, the goal must be prevention rather than repair. Fluoridation is

presently the most cost-effective method for the prevention of tooth

decay for all residents of a community.

RAVAGES OF DENTAL CARIES

One writer, Herschel S. Horowitz, DDS, MPH, has described the

seriousness of dental caries in children from a personal perspective:

In 1960, when I started to work as a public health dentist and began to conduct trials

and epidemiologic surveys, dental caries was a scourge. It was ubiquitous and a cause

of widespread affliction and pain. For example, the [1958] baseline dental caries

examinations of all schoolchildren attending Elk Lake School in Pennsylvania, a school

water fluoridation site...showed that children in that area with fluoride-deficient

drinking water had an average of 13.51...DMFS. The most recent national survey of U.S.

school children, done in 1986-87, showed that the mean had dropped to 3.07, with

relatively little difference between fluoridated and nonfluoridated areas. The same

surveys showed that caries in approximal tooth surfaces declined, on average, from

4.78 to 0.37 per child between 1958 and 1986-87. Complex, two-and three-surface

cavities or restorations were commonplace....

Mean values are totally inadequate to portray the morbidity of dental decay 35 years

ago. During dental surveys I conducted during the 1960s, I would see scores of

children each day with teeth riddled with untreated caries, frequently causing irregular,

unsightly black craters in anterior teeth...Many would have severely decayed molars

with hypertrophic, necrotic pulps, which cause great anguish and forced them to avoid

eating or even brushing their teeth on that side of their mouths. Children with

bilaterally affected teeth such as those Ive described were truly tormented. One

unforgettable experience for me was being told by two or three high school seniors

during one of the Pike County, Kentucky, examinations to evaluate school water

fluoridation that their parents were going to provide them with full dentures as a high

school graduation present. I could not disagree with the need for or utility of such a

gift. I have not seen dentitions like those I have described in U.S. schoolchildren in at

least 20 years..

Source: Horowitz, HS, Journal of Public Health Dentistry, Vol. 55, No. 1, Winter 1995.

The problem was as widespread as it was serious. In 1930, over 85% of

children as young as 3 years of age suffered from dental caries. Over80% of 6-year-olds had primary teeth needing restoration. Seventy


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percent of 6-to-15 year-olds had 1 or more untreated cavities in

permanent teeth. The ravages of the disease and unavailability of proper

dental treatment took its toll as the children grew older. By 15 years of

age, close to 1/2 of the children in many communities were missing at

least one permanent tooth because of decay.

Eichenbaum, Dunn, and Tinanoff have reported interesting information

related to the long-term impact of communal fluoridation on the private

practice of pediatric dentistry. A survey conducted from 1948 to 1950

showed that 86% of the pediatric patients in a private pediatric dental

practice needed restorative treatment, and nearly half of these children

required pulp therapy. The results of this survey encouraged the city

health officials to implement dental health education and preventive

programs that included communal water fluoridation. A survey of the

same practice almost 30 years later (1977 to 1979) revealed a dramatic

change in the restorative needs of the children. The majority of children

needed no restorations, and the number of teeth with pulp involvement

was negligible.

HISTORICAL BACKGROUND

In the history of fluoridation, two names stand out prominently: Dr.

Frederick McKay, a private practitioner and Dr. H. Trendley Dean of the

U.S. Public Health Service. McKay brought to the attention of the dental

profession the problem of "mottled enamel" defective calcification of

teeth giving a white chalky appearance that gradually undergoes brown

discoloration. In 1933 he successfully identified fluoride as the causal

factor for mottled enamel. He was convinced that this enamel defect

could be prevented.

Between 1933 and 1945, Dean took over the efforts of McKay by

determining the permissible levels of fluoride in drinking water that not

only would prevent the enamel defect, but also deliver the benefits of

fluoridation against dental caries. By the time fluoridation was initiated

in 1945, the idea that sodium fluoride could be safely and practically

added to water supplies was accepted by public health officials in many

communities.

Today, virtually every person in the United States receives fluoride from

one source or another. Over 144 million people drink fluoridated waterthat protects their teeth from dental caries. Other sources of fluoride


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available to the public include: toothpaste, mouth rinses, professionally

applied topical fluorides, dietary fluoride supplements, school drinking

water, beverages and foods. Most children of today have little or dental

caries, lose no teeth to decay, have ready access to professional dental

care, and as a result know nothing of the pain and suffering so vividlydescribed by Horowitz. The battle against dental caries could not have

been won without water fluoridation.

Use of Fluorides

Fluoride is a naturally occurring element that prevents tooth decay when

ingested systemically or applied to teeth topically.

The fluoride ion comes from the element fluorine. Fluorine, the 13thmost abundant element in the earths crust, is never encountered in its

free state in nature. It exists only in combination with other elements as

a fluoride compound. It is found in this form as a constituent of minerals

in rocks and soil everywhere. Water passes over rock formations

containing fluoride and dissolves these compounds, creating fluoride

ions. The result is that small amounts of soluble fluoride ions are

present in all water sources, including the oceans. Fluoride is present to

some extent in all foods and beverages, but the concentrations vary

widely. All water contains some fluoride naturally. Water fluoridation is

the process of adjusting the fluoride content of fluoride-deficient water

to the recommended level for optimal dental health. In the United States,

the optimum concentration for fluoride in the water has been

established in the range of 0.7 to 1.2 parts per million (ppm). The

specific optimum for a locality is dependent on the average annual

temperature for the region.

Effective fluoride is present in water as "ions" or electrically charged

atoms. These ions are the same whether acquired by water as it seeps

through rocks and sand, or added to the water supply under carefully

controlled conditions. When fluoride is added under controlled

conditions, dental benefits are assured. The striking similarity of dental

benefits conferred by natural fluoridation and controlled or adjusted

fluoridation, has been demonstrated in more than 100 long-term

fluoridation studies that compared natural or adjusted water supplies

with those of fluoride-deficient communities.

Action of Fluoride


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Researchers believe that there are several mechanisms by which

fluoride achieves its anticaries effect. It reduces the solubility of enamel

in acid by converting hydroxyapatite into less soluble fluorapatite; it

may exert an influence directly on dental plaque reducing the ability of

plaque organisms to produce acid; and it promotes the remineralizationof tooth enamel in areas that have been decalcified by acids. Most likely,

fluoride works by a combination of these effects. The remineralization

effect of fluoride is of prime importance because it results in a reversal

of the early caries process as well as an enamel surface that is more

resistant to decay.

Underscoring the continuing efforts necessary to extend the benefits of

fluoridation to the entire nation is the statistic that only 61% of the

population using public water supplies have access to fluoridated water.

School water fluoridation is another avenue open to public health

officials. Water fluoridation provides protection to primary teeth against

dental caries but to a somewhat lesser degree than permanent teeth.

The caries reduction benefits to primary teeth ranged between 40% and

50%, whereas the range for permanent teeth was between 50% and 60%.

School water is usually fluoridated at 4.5 times the optimum

concentration recommended for the community in which the school is

located, on the premise that children drink the water only when school

is in session. It has been established that school water fluoridation

reduces dental caries among school children more than 25%. The major

disadvantage of relying upon school water fluoridation as the sole

means of controlling dental caries is that children do not receive

benefits until they begin school, and exposure to fluoridation occurs

only during the school year and while school is in session.

Without doubt the repeated use of fluorides is of critical importance forthe control and prevention of dental caries in both children and adults.

Numerous controlled clinical investigations have consistently

demonstrated the cariostatic properties of fluoride provided in a variety

of manners. These studies have also shown that the maximal benefit

from fluoride is achieved only through the use of multiple delivery

systems.

Existing evidence indicates that the cariostatic activity of fluoride

involves several different mechanisms. The ingestion of fluoride resultsin its incorporation into the dentin and enamel of unerupted teeth; this


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makes the teeth more resistant to acid attack after eruption into the oral

cavity. In addition, ingested fluoride is secreted into saliva; although

present in low concentrations of saliva, the fluoride is accumulated in

plaque where it decreases microbial acid production and enhances the

remineralization of the underlying enamel. Fluoride from saliva is alsoincorporated into the enamel of newly erupted teeth, thereby enhancing

enamel calcification (frequently calledenamel maturation), which

decreases caries susceptibility.

The exposure of the teeth to the much greater concentrations of fluoride

present in professionally applied solutions and gels, dentifrices, and

rinses results in all the foregoing mechanisms except the presumptive

incorporation into enamel. Although it is difficult to separate the benefits

of the different mechanisms of action of fluoride, research has

suggested that the predominant mechanism involves the impact of

fluoride upon the remineralization of demineralized enamel. Numerous

studies have shown that the presence of fluoride greatly enhances the

rate of remineralization of demineralized enamel and dentin.

Moreover, tooth structure remineralized in the presence of fluoride

contains increased concentrations of fluorhydroxyapatite, making the

remineralized tissue more resistant to future attack by acids than the

original structure was. In view of these multiple mechanisms, it is not

surprising that the use of fluoride from various delivery systems has

additive benefits. This supports the recommendation that frequent

exposure to fluoride is necessary for maximal caries prevention and

control.

Carmichael and associates and Rock, Gordon, and Bradnock have

reported data in

separate studies comparing the caries incidence of children living in two

fluoridated communities with children living in two nonfluoridated

communities in England. The role of fluoridation in reducing dental

caries is obvious in both studies. The study by Carmichael and

associates also demonstrates that children in lower social classes gain

an even greater caries prevention benefit than children in higher social

classes. The reason is that, as a group, the children in the lower social

classes have a higher prevalence of proximal carious lesions, and

proximal tooth surfaces derive the greatest benefit from fluoridation.


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The protection afforded by the ingestion of fluoridated water persists

throughout the lifetime of the person. Investigations by Russell and

Elvove and by Englander and co-workers, as well as other studies, have

shown that the continuous ingestion of fluoridated water during

adulthood decreases the prevalence of dental caries by about the samemagnitude observed in children. In addition, Stamm and Banting have

reported a 56% decrease in the prevalence of root-surface caries in

adults who lived continuously in a fluoridated community.

Effectiveness of Water Fluoridation

The benefits of fluoridation can be delivered by adjusting the natural

fluoride concentration to about 1 part fluoride to 1 million parts water (1

ppm). The range of fluoride concentration in water varies from 0.7 to 1.2ppm depending on the mean daily temperature; the higher the

temperature the lower the concentration of fluoride in the water due to

greater consumption of water and vice versa.

Water fluoridation is the most cost effective and efficient method of

bringing the benefits of fluoride to a community. In early studies

children reared in a fluoridated water community showed a 50% to 70%

reduction in caries in the permanent dentition when compared to

children in a non-fluoridated community. Currently, reduction in caries

attributed to water fluoridation is 17% to 40% because of multiple

sources of fluoride.

The effectiveness of water fluoridation has been documented in

literature for more than 50 years. In a recent review of these published

data, the results of 113 studies in 23 countries were compiled and

analyzed. This information summary provided effectiveness data for 66

studies in primary teeth and for 86 studies in permanent teeth. Fifty-nine

out of the 113 studies analyzed took place in the United States. Taken

together, the modal caries reductions observed for primary teeth was

40-49% (24 out of 66 studies) and 50-59% for permanent teeth (33 out of

86 studies). When data for different age groups is isolated, the efficacy

is greatest for the deciduous dentition, with a range of 30-60 percent

less caries in fluoridated communities. In the mixed dentition (ages 8 to

12), the efficacy is more variable, about 20-40 percent less caries. In

adolescents (ages 14-17), it is about 15-35 percent less caries. Current

data on caries prevalence for adults and seniors is limited and includesseveral populations living in communities with higher than optimal


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fluoride levels. For these adults and seniors, a range of 15-35 percent

less caries would also apply.

Based on this accumulation of scientific evidence, studies on the

effectiveness of water fluoridation consistently show that children,adolescents, adults and seniors show a consistently and substantially

lower caries prevalence in fluoridated communities. However, because

of the high geographic mobility of our society and the widespread use of

fluoride dentifrices, supplements and other topical agents, such

comparisons are becoming more difficult to conduct.

Many well-documented studies have compared the decay rates of

children before and after fluoridation in the same community, as well as

with cohorts in naturally fluoridated and/or nonfluoridated communities.The earlier studies were conducted at a time when other sources of

fluoride, such as toothpastes, mouth rinses and professionally applied

fluoride gels were not available. The results from these studies were

dramatic.

Over the years, as other sources of fluoride became more readily

available, the caries reductions observed via these comparative

evaluations, although still significant, tapered off. However, more recent

data continue to demonstrate that caries prevalence is higher for

individuals who reside in nonfluoridated communities compared to

those of individuals living in fluoridated communities. The following

summary provides an interpretation for some of the historical studies

that have been conducted on the effectiveness of water fluoridation.

A 15-year landmark study in Grand Rapids, Michigan found that children

who consumed fluoridated water from birth had 50-63% less tooth decay

than children who had been examined during the original baseline

survey. Ten years after fluoridation, 6-to-9-year-olds in Newburgh, New

York were experiencing 58% less tooth decay than their counterparts in

Kingston, New York, which was fluoride deficient. After 15 years, 13-to-

14-year-olds in Newburgh (fluoridated) had 70% less decay than the

children in Kingston.

After 14 years of fluoridation in Evanston, Illinois 14-year-olds had 57%

fewer decayed, missing or filled teeth than control groups drinking water

low in fluoride. A classic study conducted in Brantford-Sarnia-Stratford,Canada, demonstrated that the caries rates of teenagers living in the two


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fluoridated communities, Stratford (naturally fluoridated) and Brantford

(fluoridated by adjustment), were significantly lower than the decay

rates of teenagers living in fluoride deficient Sarnia.

In 1981, a study in Britain compared the decay rates in Newcastle onTyne (fluoridated) with those of children from Northumberland

(nonfluoridated). During a five-year period, 1976-1981, caries experience

in both localities had fallen by more than one third. However, the decay

rates were considerably lower in Newcastle, 59% lower in 1976 and 58%

lower in 1981, than they were in nonfluoridated Northumberland.

In 1983, a similar study was undertaken in North Wales to determine if

the caries prevalence of fluoridated Anglesey continued to be lower than

that of Arfon in nonfluoridated Gwynedd, as was indicated in a previoussurvey conducted in 1974. Decay rates of life-long residents in Anglesey,

aged 5,12 and 15, were compared with those of similar aged residents in

nonfluoridated Arfon. Examiners were not aware of which children lived

in the fluoridated and nonfluoridated communities. Study results

demonstrated that, while a decline in caries had occurred since the

previous survey in 1974, the decay rates were relatively comparable in

both communities. The mean decay rate of the children in fluoridated

Anglesey, in 1983, was still 45% lower than those living in nonfluoridated

Arfon. These findings indicate a continuing need for fluoridation

although caries levels have declined.

Continued Success With Fluoridation

Numerous studies conducted over the past several years indicate a

generalized trend toward a decreased caries prevalence in children

living in the United States. This trend also has been reported for

children in some foreign countries. Factors that most likely explain

these findings include the increased use of fluorides, particularly

toothpaste, as well as increasing awareness by the public about the

effects of diet on dental health. Still, the level of caries reduction

recently achieved through water fluoridation in industrialized countries

appears to range between 30-60% for children with deciduous teeth, 20-

40% for children with mixed dentitions and 15-35% for adolescents and

adults. In addition, fluoridation is still the safest, most cost-effective and

most equitable method of reducing tooth decay in a community.


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In the 1940s, children in communities with fluoridated drinking water

had reductions in caries scores of approximately 60% as compared to

those living in nonfluoridated communities. Recent studies reveal that

caries scores are lower in naturally or adjusted fluoridated areas;

however, the difference between fluoridated and nonfluoridated areas isnot as great as in the 1940s. This change is likely explained by the

presence in nonfluoridated areas of fluoride in food, beverages, dental

products and dietary supplements. While this reduction in decay is not

as dramatic as it was twenty-five years ago, it continues to be clinically

significant when compared with non-fluoridated areas.

The most recent nationwide survey of 40,000 schoolchildren revealed

that 50% of children aged 5- 17 had no decayed, missing or filled

permanent teeth. The results of the survey also indicated that decay of

the smooth surfaces between the teeth had decreased 54% between

1980 and 1987, while the prevalence of decay in other tooth surfaces had

dropped 32% during the same period. This dramatic decline in decay

scores of U.S. children is attributed primarily to the widespread use of

fluoridein community water supplies, toothpastes, supplements and

mouth rinses. In a previous survey conducted in 1979-1980, researchers

found that children who had a continuous history of water fluoride

exposure had an average of 33% fewer decayed teeth than children whohad resided in nonfluoridated communities.

A British study conducted in 1987 compared the decay scores for 14-

year-old children living in South Birmingham, fluoridated since 1964,

with those of children the same age living in nonfluoridated Bolton.

Socioeconomically, the cities are similar. Two hundred thirty-four (234)

children attending 12 schools in South Birmingham, and 275 children

attending nine schools in Bolton were examined. The average decayed,

missing, and filled tooth score for the children of South Birmingham was2.26, compared to an average score of 3.79 for children in nonfluoridated

Bolton. These scores indicate a statistically significant difference of 40%

between the decay rates in the two cities. Because of the similarity in

social and demographic factors, the investigators have attributed

difference in caries experience found in this study to differences in

water fluoride level.

In 1984, OMullane studied the effectiveness of water fluoridation in the

prevention of dental caries in Irish children. The results revealed that theprevalence of dental caries was significantly lower in lifetime residents


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of fluoridated communities. Comparison of the 1984 data with similar

data collected between 1961 and 1963 showed that there was a major

decline in the level of dental caries in Irish children, the decline being

greatest among younger children and residents of fluoridated

communities.

Unlike the situation in the 1950s and 1960s, today people living in non-

fluoridated areas receive fluoride from a variety of sources including

toothpastes, mouth rinses, professionally applied fluoride gels and

fluoride supplements. As a result of the widespread availability of these

various sources of fluoride, the difference between decay rates in

fluoridated areas versus nonfluoridated areas has diminished.

Cost-Effectiveness of Fluoridation

The cost of water fluoridation is extremely low. In large cities, including

the labor costs and chemicals used, it may cost from 14 cents to 21

cents per person annually to fluoridate the water. In medium-size cities

the cost is estimated to be 18 cents to 75 cents per person annually, and

in small-size cities the cost rises to 71 cents to $5.48 person per annum.

The annual cost of community water fluoridation averages about 51

cents per person in the United States, depending mostly on the size of acommunity, labor costs, and type of chemicals and equipment utilized.

With the escalating cost for health care, fluoridation remains a

preventive measure that benefits all members of the community at

minimal cost.

The cost to purchase fluoride chemicals has remained fairly constant

over the years in contrast to the continued rising cost of dental care. In

1981, the fee for restoring one permanent tooth with a two surface

amalgam filling was about $20.00. By 1990, that fee had more than

doubled to an average of $42.00 the approximate cost of providing

fluoridation to an individual for a lifetime. School-based dental disease

prevention activities such as fluoride mouthrinse or tablet programs,

professionally applied topical fluorides, dental health education,

brushing, and flossing have not been found to be as cost-effective in

preventing tooth decay as community water fluoridation. Fluoridation

remains the most cost-effective and practical form of preventing caries

in the United States and other countries with established municipalwater systems.


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The age of the population at the time water fluoridation is introduced will

influence the overall economic benefits. The need for restorative dental

care is lower in fluoridated communities. Therefore, an individual

residing in a fluoridated community will have fewer restorative dental

expenditures during a lifetime. There are also many indirect benefitsfrom the prevention of dental decay, such as reduction in pain, a more

positive self image, fewer missing teeth, fewer teeth requiring root canal

treatment, reduced need for dentures and bridges, fewer cases of

malocclusion aggravated by tooth loss, and less time lost from school

or work from dental disorders or visits to the dentist. These intangible

benefits are impossible to measure economically and are often taken for

granted.

Fluoridation has been estimated to have a cost-benefit ratio of about

1:80; that is every dollar invested in fluoridation saves approximately

eighty dollars ($80) in dental expenditures.

The economic importance of fluoridation is underscored by the fact that

frequently the cost of treating dental disease is paid not only by the

affected individual, but also by the general public through services

provided by health departments, welfare clinics, health insurance

premiums, the military, and other publicly supported medical programs.

Fluoridation For Adults

Fluoride has both a systemic and topical effect and is beneficial to

adults in two ways. The first is through the remineralization process, in

which beginning carious lesions in the enamel fail to enlarge or may

even reverse because of frequent exposure to small amounts of fluoride.

The other protective benefit is in the prevention of root caries, a

progressive lesion of the root surface, affecting adults with gingival

recession. Studies have demonstrated that fluoride is incorporated into

the structure of the root surface, making it more resistant to decay

should it become exposed as a result of gumline recession.

Older adults experience more problems with gingival recession than any

other age group, resulting in an increase of root caries. Data from the

National Survey of Adults Dental Health indicate that in 1985-1986, root

caries was found in 21% of the employed adults and in 63% of the

seniors surveyed. This is in large part due to the fact that people areretaining more teeth and living longer. Older people tend to take more


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prescription drugs, and many of these affect salivary function and

enhance the likelihood of oral disease.

Studies comparing the decay experience of people living in fluoridated

versus fluoride-deficient areas demonstrate that adults who consumefluoridated water have a lower prevalence of dental decay. Lifelong

residents of the naturally fluoridated community of Stratford, Ontario

( 1.6 ppm F), had significantly fewer surfaces with root caries (0.48 root

surfaces decayed versus 0.99) than those living in the matched, but

nonfluoridated community of Woodstock. Nearly 900 Illinois adults,

aged 18 to 59 years, living in Aurora (high fluoride) and Rockford (low

fluoride) were similarly studied. The residents of Aurora had 40% fewer

decayed, missing and filled teeth . A British study demonstrates similar

results. When adults living in a naturally fluoridated community

(Hartlepool) were compared with a fluoride-deficient community (York),

the data showed that in the fluoridated community, adults aged 45 years

and older had 44% fewer decayed tooth surfaces than their counterparts

in York.

In another study that looked at the effects of fluoridation in adults,

researchers found that for each year of exposure to fluoridated water a

0.3 reduction of decayed and filled surfaces (about one-third) was

achieved for each year of fluoride exposure. This represented a 31%

reduction of dental disease based on the average number of decayed or

filled tooth surfaces in adults with no exposure to fluoridated water.

During the past several years, other investigators have confirmed that

root caries experience is directly related to the fluoride concentration in

the drinking water. Results from preliminary studies suggest that the

lifelong consumption of fluoridated water may be capable of reducing

the prevalence of root surface caries, which is a dental health problemin the adult population.

In addition to the direct benefits, water fluoridation has several indirect

advantages as well. These include reductions in pain from dental

infections, fewer missing teeth, fewer abscessed teeth, reduced need for

dentures, fewer cases of misaligned teeth caused by early tooth loss,

and fewer school and working days lost due to dental disorders or visits

to the dentist.

Long-Term Benefits


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While the maximum protection occurs among individuals who have

consumed fluoridated water continuously from birth, benefits also

accrue for teeth already present in the mouth when fluoridation is

begun. In Newburgh, New York, 16-year-old children who had been

exposed to fluoridated water for only six years had 41% fewer decayedteeth than those in a nearby nonfluoridated community. In Mid-Cheshire,

Britain, 12-year-old children who had been exposed to fluoride for four

years had 25% fewer cavities than their cohorts in a nonfluoridated area.

Caries prevalence among adult residents aged 20-44 of naturally

fluoridated Colorado Springs, Colorado, was approximately 60% lower

than in adults of the same ages in nonfluoridated Boulder. In addition,

significantly less root surface caries has been shown to occur in older

adults who live in fluoridated communities compared with similarly aged

residents in nonfluoridated communities. Studies conducted in North

America, the United Kingdom and New Zealand, during the widespread

availability of other fluoride vehicles, revealed that in these modern

times older people living in fluoridated areas experience 40% reduction

in root caries. There seems to be no age cut-off for the benefits of

fluoridation.

Safety of Water Fluoridation

Numerous studies have shown that consumption of fluoride in

community water supplies at the level recommended for optimal dental

health has no harmful effect in humans. For generations, millions of

people have lived in areas of the United States where fluoride is found

naturally in the drinking water in concentrations as high or higher than

those recommended to prevent tooth decay. Research conducted

among these groups confirms the safety of fluoride in the water supply.

In fact, in August 1993, the National Research Council released a report,prepared for the Environmental Protection Agency (EPA), that

essentially confirmed that the currently allowed fluoride levels in

drinking water do not pose a risk for health problems such as cancer,

kidney failure, or bone disease. Based on a review of available data on

fluoride toxicity, the expert subcommittee which wrote the report

concluded that the EPAs ceiling of 4 ppm for fluoride in drinking water

is "appropriate as an interim standard." Because there is no chemical

difference between fluoride present naturally and that which is added to

the water supply, residents of communities that fluoridate their watercan be assured of its safety.


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After extensive review of the scientific literature, nearly every national

organization in the U.S. involved with health issues has adopted policies

supporting fluoridation.

The American Dental Association adopted a resolution in support offluoridation in 1950, and has repeatedly reaffirmed its position publicly

and in its House of Delegates, based on its continuing evaluation of the

safety and efficacy of fluoridation.

The American Medical Associations House of Delegates first endorsed

fluoridation in 1951. In 1986, and again in 1990, the AMA again

reaffirmed fluoridation as "an effective means of reducing dental caries"

through its governing body and via correspondence to the American

Dental Association.

The World Health Organization, which initially recommended the

practice of water fluoridation in 1958, reaffirmed its support for

fluoridation in 1984, urging member countries to consider fluoridation in

their national planning for the prevention and control of oral disease. In

1991 the U.S. Public Health Service reaffirmed its support for

fluoridation based on a comprehensive review of the literature.

Alternatives To Wafer Fluoridation

Alternative methods of making fluoride available to populations are not

nearly as cost-effective nor as reliable as water fluoridation.

Fluoridated salt comes second to drinking water as a dietary vehicle for

ensuring adequate intake of fluoride. This method of providing fluoride

to large segments of the population is currently being used in

Switzerland and has been tested in a number of countries including

Mexico, Spain, France, Hungary, and Colombia. Based on severalstudies comparing fluoridated salt with fluoridated water, it appears that

the caries-preventive effectiveness of fluoridated salt is substantial and

therefore, it may be an adequate alternative, especially for parts of the

world which do not have many communal water supplies.

However, there are several disadvantages associated with fluoridated

salt. The use of fluoridated salt with a fixed concentration of fluoride

presents problems given the wide range of fluoride concentrations

found naturally in water supplies. Moreover, the suspected role of salt in


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producing or aggravating hypertension has prompted scientists and

public health officials to recommend that people limit their salt intake.

People who are susceptible to hypertension may find this method of

receiving fluoride unacceptable.

Fluoridated milk has been suggested as another alternative to

community water fluoridation, but there are several objections to this

method as well. Milk is ingested in relatively large amounts during early

childhood and consumption usually decreases with age and many

children drink little or no milk. The monitoring of fluoride content in milk

is technically more difficult than for drinking water, because there are

many more dairies than communal water supplies. In addition, because

fluoridated milk could not be sold in areas having natural or adjusted

fluoridation, regulation would be difficult, and established marketing

patterns would be disrupted.

Other Sources of Fluoride

Dietary fluoride supplements are also used in areas where water

fluoridation is not available or is inadequate. Supplement forms include

tablets, lozenges, drops, liquids, and fluoride-vitamin combinations.

Dietary fluoride supplements are available in concentrations ranging

from 0.125 to 0.50 mg in drops, and from 0.25 to 1.0 mg in tablets and

lozenges, and 1 mg/5 ml in oral rinses. Studies have indicated that

fluoride tablets taken daily result in a 50% to 80% reduction in caries.

Tablets contain neutral sodium fluoride (NaF) or acidulated phosphate

fluoride (APF). Fluoride drops are generally suitable for infants who are

breast-fed or infants who are formula-fed and who live in a non-

fluoridated community.

A review of the literature on the value of fluorides administered during

pregnancy fails to disclose any valid evidence to support such use even

in nonfluoridated areas. In 1966, the FDA banned the manufacturers of

fluoride supplements from marketing products bearing a claim that

dental caries would be prevented in the offspring of women who used

such products during pregnancy. The FDA took this action because of

insufficient clinical evidence to substantiate such a claim. There was no

question of safety. Although some medical and dental practitioners have

continued to prescribe dietary fluoride supplements for pregnant

women since the FDAs advertising ban, generally there is unanimityamong research experts and public health officials that fluoride ingested


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by gravid women does not benefit the teeth of their offspring, at least

not the permanent teeth.

Extensive research initiated in the early 1950s ultimately resulted in the

identification of the first fluoride-containing dentifrice capable ofdecreasing the incidence of dental caries. This dentifrice contained

stannous fluoride in combination with calcium pyrophosphate as the

cleaning and polishing system and was accepted as the first therapeutic

dentifrice by the Council on Dental Therapeutics of the American Dental

Association in 1964 on the basis of more than 20 clinical trials. The

significance of this original development has been profound; in fact, a

review by Jenkins concluded that the general decline in caries

prevalence in Britain and other developed countries appears to be

attributable in large part to the widespread use of effective fluoride-

containing dentifrices.

Other sources of fluoride include topical application of fluorides (the

least cost effective as a public health measure, but may be appropriate

for special needs groups in specific programs at high risk for caries),

fluoride mouth rinses (generally suitable for school-based public

programs although hard to monitor).

The periodic professional topical application of concentrated fluoride

solutions or gels has been repeatedly demonstrated to result in a

significant reduction in the incidence of dental caries in both children

and adults as well as the arrestment of incipient lesions. As a result

professional topical fluoride applications are routinely recommended for

all children and adolescents. Even in the absence of dental caries

activity, topical fluoride applications to children are recommended as a

means of increasing the fluoride content of the enamel of newly erupted

teeth, thereby increasing the resistance of these teeth to cariesformation. Based upon the results of numerous clinical trials the ADAs

Council on Dental Therapeutics has accepted three fluoride systems for

professional topical application; these systems are 2% sodium fluoride,

8% stannous fluoride, and acidulated phosphate fluoride (ADF)

containing 1.23% fluoride.

At least one researcher has stated that the risk of using fluoride

supplements in young children outweigh the benefits. Since there are

alternative forms of fluoride to use in high risk individuals, fluoride


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supplements should no longer be used for young children in North

America.

Dietary Fluoride Supplements

For children who do not live in fluoridated communities, dietary fluoride

supplements (tablets, drops or lozenges) have been an effective

alternative to water fluoridation for the prevention of tooth decay.

The correct amount of a fluoride supplement should be based on the

natural fluoride concentration of the childs drinking water and the age

of the child. For optimum benefits, use of supplements must begin as

soon as possible after birth, and be continued daily until the child is at

least 13 years old. This need for compliance over an extended period oftime is a major economic disadvantage of this method, one that makes it

impractical as a general alternative to water fluoridation as a public

health measure.

Total costs for the purchase of supplements and administration of a

program may be small compared with the initial cost of the installation

of water fluoridation equipment. It must be noted, however, that all

children in a community benefit from adjusted water fluoridation,

whereas only a small minority benefit from fluoride supplements. Theoverall cost of supplements per child is much greater than the pro rata

cost of community fluoridation. In addition, community water

fluoridation provides decay prevention benefits for the entire population

regardless of socioeconomic status, and is particularly important for

children of poor families who may be unable to purchase regular dental

care. Lastly, water fluoridation continues to benefit the population into

adulthood.

In a controlled situation, as shown in a study involving children of health

professionals, fluoride supplements have been shown to achieve

effectiveness comparable to that of water fluoridations. However, even

with this highly educated and motivated group of parents, only half

continued to give their children fluoride tablets for the necessary

number of years. Independent reports from several countries, including

the United States, have demonstrated that community-wide trials of

fluoride supplements have generally failed as a public health measure,

largely because most parents and children are unable to maintain thedaily schedule.


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Although dietary fluoride supplements, in the absence of fluoridated

water, are effective in reducing caries, other sources of fluoride

exposure must be taken into consideration prior to the prescription of a

dietary fluoride supplement. These other sources may include exposure

to fluoride containing toothpastes, fluoride mouth rinses, andfluoridated water from sources other than the home water supply such

as school and/or day care and from processed beverages and foods

prepared with fluoridated water. For this reason, it is recommended that

dietary fluoride supplements be used conservativelyafter consideration

of all sources of water fluoride, tap and bottled and water filtration

methodsboth in the home and during child care.

Effect of Discontinuing Fluoridation

Caries prevalence will increase if water fluoridation in a community is

discontinued for an extended period. Caries reductions are greatest

where water fluoridation is available in addition to topical fluorides,

toothpaste, and fluoride rinses.

Antigo, Wisconsin began fluoridation in June 1949, and ceased adding

fluoride in November 1960. After five and one-half years without

adequate fluoride, second grade children had more than 200% more

decay, fourth graders 70% more, and sixth graders 91% more than those

of the same age in 1960. Residents of Antigo reinstitated fluoridation in

October 1965, on the basis of the severe deterioration of their childrens

dental health.

J.N. Mansbridge reported that after the cessation of fluoridation in the

British town of Kilnamock in 1962, caries rates in children aged 3-7

increased. By 1968, the number of children who were caries-free had

decreased to a similarly low number as reported in 1956 prior to

fluoridation.

Eight years after fluoridated water became available to the residents of

Wick in Northern Scotland, a government reorganization resulted in a

decision to stop fluoridation, returning the water to its suboptimal,

natural fluoride level of .02 ppm. Data collected to monitor the dental

health of the Wick children clearly demonstrated a negative health

effect. Five years after the cessation of water fluoridation, caries in

permanent teeth had increased 27% and caries in deciduous teethincreased 40%. This increase in tooth decay occurred during a period


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when there had been a reported overall reduction in caries nationally

and when fluoridated toothpaste had been widely adopted. This recent

data suggests that caries levels in children can be expected to rise

where water fluoridation is interrupted or terminated.

In a similar example, the prevalence of caries in 10-year-old children in

Stranraer, Scotland, had increased since the discontinuation of water

fluoridation, resulting in a 115% increase in the mean cost of restorative

dental treatment caused by caries and a 21% increase in the mean cost

all dental treatment. These data support the important role water

fluoridation plays in the reduction of dental decay.

A U.S. study of 6-7 year old children who had resided in optimally

fluoridated areas and then moved to the nonfluoridated community ofColdwater, Michigan revealed an 11% increase in decayed, missing or

filled tooth surfaces (DMFS) over a 3 year period from the time the

children moved. These data reaffirm that abandoning water fluoridation

and relying only on topical forms of fluoride is not an effective or

prudent public health practice based on the available evidence.

Finally, another study which reported the relationship between

fluoridated water and caries prevalence focused on the city of

Galesburg, Illinois, a community whose public water supply was

naturally fluoridated at 2.2 ppm. In 1959, Galesburg switched its

community water source to the Mississippi river. This alternative water

source offered the citizens of Galesburg with a suboptimal level of

fluoride, approximately 0.1 ppm. During this time when the fluoride

content was below optimal, data revealed a 10 percent decrease in the

number of caries-free 14 -years-olds (oldest group observed), and a 38

percent increase in detectable carious lesions. Two years later, in 1961,

the water was artificially fluoridated at the recommended level of 1.0ppm.

Opposition To Fluoridation

Opinions are seldom unanimous on any scientific subject. However,

support for fluoridation among scientists and health professionals,

including physicians and dentists, is nearly universal. Endorsement of

fluoridation by the American Dental

Association, the American Medical Association, and other nationalhealth and civic organizations came as a result of thorough


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investigation of published research and detailed evaluation. No charge

against the benefits and safety of fluoridation has ever been

substantiated by reliable scientific evidence.

For an overwhelming majority of those practicing in the healthprofessions, there is no doubt about the safety and effectiveness of

fluoridation. Unfortunately, most of the public may not be aware of the

importance of fluoridation in preventing dental decay. Additionally,

concerns by the public regarding the alleged health and safety risks of

fluoridation, which are purported by a small group of persistent and

vocal fluoridation opponents, has made it difficult for health educators

to work within the community to put the health benefit and risk issue

into proper perspective.

Of the small minority who do oppose this public health measure, some

do so for philosophical reasons; others because they generally oppose

community action on health issues, and some because they are

misinformed. Unscrupulous opponents

have used half-truths and innuendos, or misquoted statements out of

context. "Alarming" statements used by some antifluoridationists

cannot be substantiated by reputable scientific research.

Inasmuch as the nation at large has come to accept water fluoridation as

an effective means of controlling dental caries in children, there are

organized pockets of resistance in various communities against water

fluoridation. Opponents of water fluoridation use arguments such as

ineffectuality of the process, environmental concerns, government

overregulation and suspicion of government programs or officials. In

many instances, they are able to sway public opinion toward their point

of view by connecting fluoridation to concerns about health, disease,

and aging. Their scare tactics imply that water fluoridation causeshealth hazards, such as allergies, cancer, heart disease, and increased

death rates.

These opponents create an illusion of scientific controversy where there

is none. If nothing else works, the activists resort to water fluoridation

as a violation of an individuals freedom of choice.

A study conducted by the U.S. Department of Public Health on fluoride

evaluated the benefits and risks of fluoridation and, offered the followingconclusions:


22/25

Optimal fluoridation of drinking water is not a detectable cancer risk to

humans. Data available from two studies of the carcinogenicity of

fluoride in experimental animals did not report a link between fluoride

and cancer. Crippling skeletal fluorosis is not a public health problem in

the United States. Similarly, there is no support for the use of highdoses of fluoride to reduce osteoporosis and related bone fractures.

There is no evidence to suggest a link between fluoride and birth

defects, such as down syndrome, or any effect on organ systems, e.g.,

gastrointestinal.

Fluorosis

The use of fluoride as a public health measure may have come to a full

circle since the water fluoridation was initiated in 1935. Many studies arenow focusing on the risk of fluoride rather than its benefits in the control

of dental caries. Questions are being asked if there is too much fluoride

around and, if so, what we should do about it.

Certainly, there is much more fluoride around today than there was

nearly 50 years ago. In his article in Science, Leverett (Leverett DH.

Fluorides and the changing prevalence of dental caries. Science 1992;

217:26-30) suggested that the opposite trends of a decrease in the

prevalence of dental caries and an increase in abnormal fluorosis

suggests that there is a need to examine the level of fluoride exposure in

the U.S. population that would control or prevent the disease without the

risk of fluorosis.

Mottled enamel, the result of fluorosis, is defined as the chronic

endemic form of hypoplasia of dental enamel caused by drinking water

with a high naturally- occurring fluoride content during the time of tooth

formation in children. Defective calcification of teeth gives a white

chalky appearance that gradually undergoes brown discoloration.

Fluorosis may result from naturally-occurring excessive fluoride levels

in drinking water, from children swallowing excessive amounts of

fluoride-containing dentifrices, or from inappropriate supplementation

with fluoride tablets or fluoride-containing vitamins. The mottled enamel

effect varies from small fine, lacy markings to white specks, to severe

pitting with heavily stained, and friable enamel.

There are many findings that show that the children of today suffer fromenamel fluorosis to a greater degree than the children of the 1940s,


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which in turn indicates that fluoride ingestion in the U.S. population has

increased substantially, and that the use of some fluoride products such

as dietary supplements and tooth paste can result in fluorosis. The

other side of the scale is that the incidence of dental caries has declined

substantially, so the challenge lies in determining the level of fluorideexposure that provides maximum dental health benefits with an

acceptable level of risk for enamel fluorosis.

The relation between the dental caries experience and extent of fluorosis

in various communities in relation to the fluoride content of drinking

water is indicated in Fig. 1. This figure concerns observations of the

permanent teeth of 7000 children 12 to 14 years old who were lifelong

residents of communities with the designated fluoride content and who

had never left their communities for more than 1 month. The average

number of decayed, missing and filled teeth decreases from 8 at very

low concentrations of fluoride in drinking water (0.1 ppm) to less than 3

when the fluoride content is approximately 1 ppm.

The index of fluorosis remains near zero with increasing fluoride

concentrations in drinking water until concentrations reach values

greater than 1.0 ppm. With further increases in fluoride concentration of

the drinking water, the index of fluorosis rises steeply.

The exposure to fluoride, of course, is not uniform in the entire

population; many children receive several times the amount of fluoride

that an average child receives. Sources of food and beverage products

that may contain sizable concentrations of fluoride include: infant

formulas, particularly when reconstituted with fluoridated drinking

water; infant foods, especially cereals; sea foods and poultry products

that are mechanically boned; soft drinks and reconstituted juice

products processed with fluoridated drinking water and, to a lesserextent, teas.

Moreover, most children in the United States use fluoride-containing

toothpaste with concentrations that range from 1,000 - 1,500

parts/million (ppm) and many take dietary fluoride supplements, some of

whom should not be taking them at all, because their drinking water

contains sufficient concentrations of fluoride, and others who are

prescribed inappropriate dosages because of ignorance or negligence

of their physicians or dentists. Swallowing or overenthusiastic use of


24/25

fluoridated toothpaste may also contribute to higher levels of fluoride

ingested by children.

Although it is hard to establish a direct relationship between the use of a

particular agent or product and dental fluorosis, sufficient data exist toshow that the prevalence of fluorosis is associated with the fluoride

concentration of drinking water, the use of dietary fluoride supplements,

the early use of dentifrices, and the prolonged use of infant formula.

There is not enough evidence to link fluoride mouth rinses,

professionally-applied fluorides, bottled waters, carbonated beverages

and juices to fluorosis.

The public opinion on the use of fluoride has swung to the other side so

that the levels of fluorosis which would have been previously acceptableduring a period of high caries rates is not so readily acceptable now.

Community water fluoridation is still the most effective and popular

means of delivering optimal levels of fluoride to a large segment of the

population.

References

1.American Dental Association. Fluoridation Facts. 1993.

2.Carmichaels CL and other: The effect of fluoridation upon relationship betweencaries experience and social class in 5-year-old children in Newcastle and

Northumberland,BR Dent J149;163-167, 1980.

3.Centers for Disease Control and Prevention. Public health focus; fluoridation of

community water systems.MMWR Morb Mortal Wkly Rep1992;41:372-81.

4.Englander HR, Reuss RC, Kesel RG: Dental caries in adults who consume

fluoridated versus fluoride-deficient water,JADA68:14-19, 1964.

5.Horowitz, HS,Journal of Public Health Dentistry,Vol. 55, No. 1, Winter 1995.

6.Leverett DH. Fluorosis and the changing prevalence of dental caries.Science

1982;217: 26-30.

7.Leverett DH. Prevalence of dental fluorosis in fluoridated and nonfluoridated

communitiesa preliminary investigation.J Public Health Dent1986;46:184-7.

8.McDonald RE, Avery, DR. Dentristry for the child and adolescent.Mosby, St.

Louis 1994.

9.Rock WP, Gordon PH, Bradnock G: Dental caries experience in Birmingham

and Wolverhampton school children following the fluoridation of Birmingham

water in 1964,Br Dent J150;61-66, 1981.

10.Rozier RG. A new era for community water fluoridation? Achievements after

one-half century and challenges ahead.J Public Health Dent1995; 55(1):3-5.

11.Russell AL, Elvolve E: Domestic water and dental caries. VIII A study of the

fluoride-dental caries relationship in an adult population,Public Health Rep.

66:1389-1401, 1951.


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12.Stamm JW, Banting DW: Comparison of root caries prevalence in adults with

life-long residence in fluoridated and non-fluoridated communities,J. Dent Res

59;405 (abst 552), 1980.

fluoride for caries control

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