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Fluoride compounds are constituents of minerals in rocks and soils.
Water passes over rock formations and dissolves the fluoride compounds
that are present, 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.
(Safe Drinking Water Committee, National Research
Council. Drinking water and health. National Academy
of Sciences. Washington, DC; 1977; Largent E. The supply
of fluoride to man: 1. Introduction. In: Fluorides and human
health. World Health Organization Monograph Series No. 59. Geneva;
1970:17-8; Levy SM, Kiritsy MC, Warren JJ. Sources of fluoride
intake in children. J. Public Health Dent 1995;55(1):39-52.)
Researchers have observed fluoride's decay preventive
effects through three specific mechanisms:
1. It reduces the solubility of enamel in acid by converting
hydroxy apatite into less soluble fluor apatite;
2. It exerts an influence directly on dental plaque by reducing the
ability of plaque organisms to produce acid; and
3. It promotes the remineralization or repair of tooth enamel in
areas that have been demineralized by acids.
(Mellberg JR, Ripa LW. Fluoride in preventive
dentistry: theory and clinical applications. Chicago:
Quintessence;1983:41-80; DePaola PF, Kashket S. Prevention
of dental caries. In: Fluorides, effects on vegetation, animals
and humans. Schupe JL, Peterson HB, Leone NC, eds. Salt Lake City:
Paragon Press;1983:199-211; Backer-Dirks O, Kunzel W, Carlos
JP. Caries-preventive water fluoridation. In: Progress in
caries prevention. Ericsson Y, ed. Caries Res 1978;12(Suppl
1):7-14.)
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2. What is water fluoridation?
Water fluoridation is the adjustment of the natural fluoride concentration
of fluoride deficient water to the level recommended for optimal
health.
Community water fluoridation is the adjustment of the natural fluoride
concentration in water up to the level of recommended for optimal
dental health (a range of 0.7 to 1.2 ppm). Optimal levels of fluoride
(a range of 0.7 to 1.2 ppm) may be present in the water naturally
or by adjusted means.
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3. Is there a difference in the
effectiveness between naturally occurring fluoridated water (at
optimal fluoride levels) and water that has fluoride added to reach
the optimal level?
No. The dental benefits of optimally fluoridated
water occur regardless of the source of fluoride.
When fluoride is added under controlled conditions to
fluoride-deficient water, the dental benefits are the same as those
obtained from naturally fluoridated water. Fluoridation is
merely a supplementation of the naturally occurring fluoride present
in all drinking water sources.
Some individuals mistakenly use the term "artifical fluoridation" to imply that the process of water fluoridation is unnatural and
that it delivers a foreign substance into a water supply when, in
fact, all water sources contain some fluoride. Community water fluoridation
is a natural way to improve oral health.
(Horowitz HS. American Journal of Public Health 1997;87(7):1235-6.
Letter to the editor.)
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Prior to the initiation of "adjusted" water fluoridation, several classic epidemiological studies were conducted which compared
naturally occurring fluoridation water to fluoride-deficient water.
Strikingly low decay rates were found to be associated with the
continuous use of water with fluoride content of 1 part per million.
(Dean HT, Arnold FA, Elvove E. Domestic water and dental caries.
Public Health Reports 1938;53(33):1443-52.)
4. Is further proof of the effectiveness
of water fluoridation needed?
Overwhelming evidence already exists to prove the effectiveness
of water fluoridation.
A controlled study conducted in 1990 demonstrated that average
tooth decay experience among school children who were lifelong residents
of communities having low fluoride levels in drinking water was
61-100% higher as compared with tooth decay experience among school
children who were lifelong residents of a community with an optimal
level of fluoride in the drinking water.
(Selwitz RH, Nowjack-Raymer RE, Kingman
A, Driscoll WL. Dental caries and dental fluorosis among schoolchildren
who were lifelong residents of communities having either low or
optimal levels of fluoride in drinking water. J Public Health Dent
1998;58(1):28-35.)
In addition, the findings of this study suggest that community
water fluoridation still provides significant public health benefits
and that dental sealants can play a significant role in preventing
tooth decay.
In 1993-4, an oral health needs assessment of children
in California found that children in grades K-3, whose families
were lifetime residents of nonfluoridated communities and whose
income was below 200% of the Federal Poverty Level, had 39% more
decay in their baby teeth when compared to counterparts who were
lifetime residents of optimally fluoridated areas.
(Selected findings and recommendations from the
California oral health needs assessment of children, 1993-94.
The oral health of California's children: a neglected epidemic.
San Rafael, CA: The Dental Health Foundation 1997.)
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5. What happens if water fluoridation
is discontinued?
Dental decay can be expected to increase if water fluoridation
in a community is discontinued for one year or more, even if topical
products such as fluoride toothpaste and fluoride rinses are widely
used.
A U.S. study of 6- and 7-year-old children who had resided in optimally
fluoridated areas and then moved to the nonfluoridated community
of Coldwater, Michigan, revealed an 11% increase in decayed, missing
or filled tooth surfaces (DMFS) over a 3-year period from the time
the children moved. This data reaffirms that relying only on topical
forms of fluoride is not an effective or prudent public health practice.
(Newbrun E. Effectiveness of water fluoridation.
J Public Health Dent 1989;49(5):279-89; Burt BA, Eklund SA,
Loesche WJ. Dental benefits of limited exposure to fluoridated
water in childhood. J Dent Res 1986;61(11):1322-5.)
Decay reductions are greatest where water fluoridation is available
in addition to topical fluorides, fluoride toothpaste and fluoride
rinses.
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6. Is water fluoridation still an effective
method for preventing dental decay?
Water fluoridation continues to be a very effective method for
preventing tooth decay for children, adolescents and adults.
Continuing assessment, however, is important as the
patterns and extent of dental decay change in populations.
Although other forms of fluoride are available, persons in nonfluoridated
communities continue to demonstrate higher dental decay rates than
their counterparts in communities with water fluoridation.
Community water fluoridation remains the safest, most cost-effective
and most equitable method of reducing tooth decay in a community
in the United States and in other countries.
(Horowitz HS. The effectiveness of community
water fluoridation in the United States. J Public Health Dent 1996;56(5
Spec No):253-8.) Water fluoridation is highly effective
in preventing decay in baby teeth, especially in children from low
socioeconomic groups. (Evans DJ, Rugg-Gunn AJ, Tabari ED,
Butler T. The effect of fluoridation and social class on caries
experience in 5-year-old Newcastle children in 1994 compared with
results over the previous 18 years. Comm Dent Health 1996;13:5-10.)
Data from the Third National Health and Nutrition Examination Survey
(NHANES III), conducted from 1988 to 1991, yielded weighted estimates
for over 58 million U.S. children. Nearly 55% of the children
aged 5 to 17 years had no decay in their permanent teeth.
(Kaste LM, Selwitz RH, Oldakowski RJ, Brunelle
JA, Winn DM, Brown LJ. Coronal caries in the primary and permanent
dentition of children and adolescents 1-17 years of age: United
States, 1988-1991. J Dent Res 1996;75(Spec Iss):631-41.)
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7. Is tooth decay still a serious problem?
Yes. Tooth decay or dental decay is an infectious disease that
continues to be a significant oral health problem.
Tooth decay is, by far, the most common and costly oral health
problem in all age groups.
(US Department of Health and Human Services,
Public Health Service. Toward improving the oral health of
Americans: an overview of oral status, resources on health care
delivery. Report of the United States Public Health Service Oral
Health Coordinating Committee. Washington, DC; March 1993.)
A dramatic increase in tooth loss occurs among people 35 through
44 years of age. The two leading causes of tooth loss in this
age group are dental decay and periodontal diseases.
(US Department of Health and Human Services.
Healthy People 2010 Objectives; Draft for public comment.
(Oral Health Section) Washington, DC: US Government Printing Office;
September 15, 1998.)
Decay continues to be problematic for middle-aged and older adults,
particularly root decay because of receding gums. In addition
to its effect in the mouth, dental decay can affect general well-being
by interfering with an individual's ability to eat certain foods
and by impacting an individual's emotional and social well-being
by causing pain and discomfort. Sometimes the pain is unbearable.
Tooth decay, particularly in the front teeth, can detract from appearance,
thus affecting self esteem.
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8. Do adults benefit from fluoridation?
Fluoridation plays a protective role against dental decay throughout
life, benefitting both children and adults. In fact, inadequate
exposure to fluoride places children and adults in the high risk
category for dental decay.
Fluoride has both a systemic and topical effect and is beneficial
to adults in two ways. The first is through the remineralization
process in enamel, in which early decay does not enlarge, and can
even reverse, because of frequent exposure to small amounts of fluoride.
Another protective  benefit
for adults is the prevention of root decay. Adults with gumline
recession are at risk for root decay because the
root surface becomes exposed to decay-causing bacteria in the mouth.
In addition to gumline recession, older adults tend to experience
decreased salivary flow, or xerostomia, due to the use of medications
or medical conditions.
(Papas AS, Joshi A, MacDonald SL, Maravelis-Splagounias
L, Pretara-Spanedda P, Curro FA. Caries prevalence in xerostomic
individuals. J Can Dent Assoc 1993;59(2):171-9; Jones JA. Root caries:
prevention and chemotherapy. AM J Dent 1995;8(6):352-7.)
Inadequate saliva flow places an individual in the high risk category
for decay. This decrease in salivary flow can increase the likelihood
of dental decay because saliva contains many elements necessary
for early decay repair - including fluoride.
9. Are dietary fluoride supplements effective?
For children who do not live in fluoridated communities, dietary
fluoride supplements are an effective alternative to water fluoridation
for the prevention of tooth decay.
(Horowitz HS. The future of water fluoridation
and other systemic fluorides. J Dent Res 1990;69(Spec Iss):
760-4.)
Dietary fluoride supplements are available in two forms: drops
for infants aged six months and up, and chewable tablets for children
and adolescents. In order to decrease the risk of dental fluorosis
in permanent teeth, fluoride supplements should only be prescribed
for children living in nonfluoridated areas. For optimum benefits,
use of supplements should begin at six months of age and be continued
daily until the child is at least 16 years old.
(American Dental Association, Council on Access
Prevention and Interprofessional Relations. Caries diagnosis
and risk assessment: a review of preventive strategies and management.
J Am Dent Assoc 1995;126(Suppl).)
The need for compliance over an extended period of time is a major
procedural and economic disadvantage, one that makes them impractical
as an alternative to water fluoridation as a public health measure.
Even with a highly educated and motivated group of parents only
half continued to give their children fluoride tablets for the necessary
number of years.
(Arnold FA, McClure FJ, White CL. Sodium
fluoride tablets for children. Dental Progress 1960;1(1):8-12.)
While total cost for the purchase of supplements are small, the
overall cost of supplements per child is much greater than the per
capita cost of community fluoridation. In addition, community water
fluoridation provides decay prevention benefits for the entire population
regardless of age, socioeconomic status, educational attainment
or other social variables. This is particularly important
for families who do not have access to regular dental services.
(Horowitz HS. The effectiveness of community
water fluoridation in the United States. J Public Health Dent 1996;56(5
Spec No):253-8.)
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10. In areas where water fluoridation
is not feasible because of engineering constraints, are alternative
to water fluoridation available?
Yes. Some countries outside the United States which do not have
piped water supplies that can accommodate community water fluoridation
have chosen to use salt fluoridation.
Studies evaluating the effectiveness of salt fluoridation outside
the U.S. have concluded that fluoride delivered via salt produces
decay reductions similar to that of optimally fluoridated water.
(Marthaler TM, Mejia R, Vines JJ. Caries-preventive
salt fluoridation. Caries Res 1978;12(Suppl 1):15-21.)
Salt fluoridation has several disadvantages that do not
exist with water fluoridation. There is a general agreement that
a high consumption of sodium is a risk factor for hypertension.
People who have hypertension or must restrict their salt intake
may find salt fluoridation an unacceptable method of receiving fluoride.
Fluoridated milk has been suggested as another alternative
to community water fluoridation in countries outside the United
States. Studies among small groups of children have demonstrated
a decrease in dental decay rates due to consumption of fluoridated
milk; however, these studies were not based on large-scale surveys.
More research is needed before milk fluoridation can be recommended
as an alternative to water or salt fluoridation.
(Pakhomov GN. Objectives and review of
the international milk fluoridation program. Adv Dent Res 1995;9(2):110-1.)
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11. Can the consistent use of
bottled water result in individuals missing the benefits of optimally
fluoridated water?
Yes. The majority of bottled waters on the market do
not contain optimal levels of (0.7-1.2 ppm) of fluoride.
The fluoride content of bottled water can vary greatly.
In a 1991 study of 39 bottled water  samples, 34 had fluoride levels
below 0.3 ppm. If the fluoride level is not shown on the label of
the bottled water, the company can be contacted,
or the water can be tested to obtain this information.
The fluoride level should be tested periodically if the source of
the bottled water changes and, at a minimum, on a yearly basis.
Flaitz CM, Hill EM, Hicks MJ. A survey of bottled
water usage by pediatric dental patients: implications for dental
health. Quintessence Int 1989;20(11):847-52.)
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12. Can home water treatment
systems (e.g. water filters) affect optimally fluoridated water
supplies?
Yes. Some types of home water treatment systems can
reduce the fluoride levels in water supplies potentially decreasing
the decay-preventive effects of optimally fluoridated water.
Individuals who drink water processed by home water treatment systems
as their primary source of water could be losing the decay preventive
effects of optimally fluoridated water available from their community
water supply. Therefore, consumers should seek advice from their
dentist about specific fluoride needs.
Consumers using home water treatment systems should
have their water tested at least annually to establish the fluoride
level of the treated water. More frequent testing may be needed.
Testing is available through local and state health departments.
Private laboratories may also offer testing for fluoride levels
in water.
Information regarding the existing level of fluoride
in a community's public water supply can be obtained by asking a
local dentist, contacting the local or state health department,
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