Fluoridated Water Does Not
by Mark D. Gold
Prevent Tooth Decay
I will cover two areas in this section. I will list a selection of
information which shows that fluoridation is not helping to prevent
dental decay. At the same time, I will comment on how the Dental Trade
Organizations have used flawed studies to convince dentists
that fluoridation was useful. I will preface those comments with:
For this discussion, remember that in the U.S., Trade Organizations like
the American Dental Association (ADA) recommend that water should
be fluoridated to 1 part per million (1ppm), although they allow for
variations depending upon the climate (.7 ppm - 1.2 ppm).
Also, please remember that the original studies by H. Trendly Dean
on fluoridation which led to the decision to allow fluoridation of
municipal water supplies
- Were worthless by his own criteria.
- Did not consider other minerals in the water.
- Did not consider the differences between "natural fluoride"
(e.g., CaF) and fluoride waste products (e.g., NaF).
- Only reported his chosen selection of data -- a subsection of the
- Had little or no statistical analysis.
- Included no safety experiments except for dental fluorosis.
- Yiamouyiannis, J. "Water Fluoridation and Tooth Decay: Results
From the 1986-1987 National Survey of U.S. Schoolchildren"
Fluoride, Journal of The International Society for Fluoride
Research (Volume 23, No. 2; April 1990; pp 55-67).
This study showed, once and for all, that fluoridation of the
U.S. water supply was worthless, at best.
Summary: Data from dental examinations of 39,207 schoolchildren,
aged 5-17, in 84 areas throughout the United States are analyzed.
Of these areas, 27 had been fluoridated for 17 years of more (F),
30 had never been fluoridated (NF), and 27 had been only partially
fluoridated or fluoridated for less than 17 years (PF). No
statistically significant differences were found in the decay
rates of permanent teeth or the percentages of decay-free children
in the F, NF and PF areas. However, among 5-year-olds, the decay
rates of the deciduous teeth were significantly lower in F than in
Average-age-adjusted DMFT [Decayed, Missing, Filled Teeth] rates
for 39,207 U.S. schoolchildren and 17,336 lofe-long resident
schoolchildren in 84 areas throughout the United States. Standard
deviations are given in parentheses.
---------------- Total --------------- Life-Long --
As you can see, there are no statistical differences in
decayed, mission, or filling teeth for U.S. children aged 5-17.
Yes, there is a stastically significant advantage in DMFT for
5-year-olds. However, by age 6, that advantage disappears. The
suspected cause for the one-year, temporary benefit is slightly
delayed tooth eruption in fluoridated water drinkers. Whatever
the cause, remember, there are no statistically significant
difference after age 5.
Recently, Brunelle used the same data to "prove" a statistically
significant advantage in dental decay in fluoridated sections of
the U.S. ("Caries Attack in the Primary Dentition of U.S.
Children" J. Dent. Research 69(Special Issue): 180 [Abstr. No. 575],
1990.) However, Brunelle used only one year (5-year-olds) of
the data that was gathered in the national survey: 5 to 17
years old! As was mentioned above, this slight advantage in
fluoridation disappears after age 5 and is likely caused by
slightly delayed tooth eruption in 5-year-olds. By picking
tiny subsections of data collected, a researcher can prove
whatever he or she wants! This is not the only time this flawed
data analysis technique was used in fluoridation research.
Also, this study points to the fact that other studies which
relied to a large extent on 5-year-olds and few older children
may also show skewed results.
In another poor study, Brunelle and Carlos used more complete
survey data to seemingly "prove" the advantages of fluoridation.
("Recent Trends in Dental Caries in U.S. Children and the Effect
of Water Fluoridation" J. Dental Research, 69(Special Issue):
723-728, 1990). This time Brunelle used more data than above,
but made many other sloppy errors as pointed out by Yiamouyiannis.
- "It contains extremely serious errors. For example, by a
cursory inspection, we found two values that are off by 100%
or more. In their Table 9, the DMFS figure for life-long F
exposure residents of Region VII should be about 3, not 1.46
as reported. Form their Table 3, the percent of 5-year-olds
who have caries is 1.0%, not the 2.7% that can be calculated
from the table. When I pointed out this error to Dr. Carlos
he admitted that only 19 out of the 1851 5-year-olds had
caries (19/1851 = 1%), but refused to make the correction."
- "It fails to report the tooth decay rates for each of the 84
geographical areas surveyed. This covers up the fact that
there is no difference in the tooth decay rates of the
fluoridated and nonfluoridated areas surveyed. The Brunelle/
Carlos study even fails to list the areas studied. As a
result, they produce misleading illustrations; for example,
their Figure 3 implies that Arizona and New Mexico have the
lowest tooth decay rates, when, in fact, not a single area
was surveyed in either of the two states."
- "It fails to do the statistical analysis (or even provide
the data, i.e., the standard deviation and sample number)
necessary to determine whether the values found for F and
NF areas are significantly different."
- "It fails to report the data for the approximately 23,000
schoolchildren who were not life-time residents of either
the F or NF areas (the partially fluoridated, PF group)....
He goes on to point out other significant flaws in this Brunelle
and Carlos study.
- Steelink C., Fowler M, Osborn M et al. Findings and
recommendations of subcommittee on fluoridation. City of
Tuscon AZ 1992 (PO Box 27210).
Also see: Chemical and Engineering News (7/27/92).
A study of Tuscon elementary children was performed by Cornelius
Steelink, Professor Emeritus, Department of Chemistry, University of
Arizona. The study was performed in order to determine the
"benefits" of water fluoridation.
They compared tooth decay versus fluoride content in a child's
neighborhood drinking water for 26,000 elementary school children.
Here are the results:
"...a positive correlation was revealed. In other words, the
more fluoride a child drank, the
more cavities appeared in the teeth.
He goes on to state:
"Since this was an unusual result, our subcommittee looked for other
relevant factors. Family incomes was compared to tooth decay. An
excellent inverse relation was found for these 26,000 children: the
higher the income, the lower the number of decayed teeth. Other
anecdotal evidence gathered by our committee included lack of access
to dental facilities, poverty, diet, and oral hygiene as contributing
factors to tooth decay in this group of children.
In the final report, the subcommittee stated that there was no
obvious relation of fluoride content in municipal water to the
prevention of tooth decay in Tucson, and because there are multiple
causes of tooth decay, a decision to fluoridate would still leave
pockets of poor dental health in Tucson. .... However, when the full
Citizens Water Advisory Committee reviewed our report in June 1992,
it recommended (on a split vote) that the city council go ahead and
fluoridate the water. The principal argument for this vote was:
'Even though fluoridation doesn't appear to be effective, let's rely
on the advice of the public health officials. After all, they're the
I saw a graph with the percentage of tooth decay plotted against
fluoride concentration. As soon as it goes over .6 ppm, the decay
goes way up.
- "Influence of social class and fluoridation on child dental
health" Community Dentistry and Oral Epidemiology 13 37-41
This study examined the influence of social class (environmental
and lifestyle factors, diet, etc.) and fluoridation on dental
health. It showed that dental health as continued to improve
equally in both fluoridated and unfluoridated areas and that the
level of dental health was strongly related to social class.
A similar result (with slightly better teeth in unfluoridated
areas) was found in Colquohoun J. "Child dental health differences in
New Zealand" Community Health Studies 11 85-90 1987.
The last two sections (2, 3) show that it is not lack of fluoride
that leads to decay but things such as "lack of access to dental
facilities, poverty, diet, and oral hygiene." A number of
studies were performed by persons interested in keeping the
fluoridation myth alive. One way to skew the results was to
compare two areas, one fluoridated and one non-fluoridated but
not take into account other factors. If a non-fluoridated
area with lack of dental facilities, poverty, poor diet and
hygiene was compared against a nearby, yet more well-to-do
fluoridated area, it becomes very easy to "prove" (wink, wink)
that fluoridation is beneficial. This type of nonsense was done
several times in order to keep the fluoridation myth alive.
One of many studies that have this flaw is:
Jackson, D., et al. "Fluoridation in Anglesey 1983: a
Clinical Study of Dental Caries" British Dental Journal 1985:
The two areas being compared, while adjacent, were vastly
- Ziegelbecker RC, Ziegelbecker R. "WHO data on dental caries and
natural water fluoride levels." Fluoride 26 263-266 1993.
Ziegelbecker R. "Fluoridated water and teeth" Fluoride 14
Both of these studies are from large data set showing that there
is no correlation between caries and fluoride concentration and no
improvement in dental health from fluoride. In the 1981 study,
for example, Ziegelbecker made of random sampling of all available
data on caries prevalence. He selected 48,000 12-14 year-old
children from 136 community water supplies in seven countries.
- Diesendorf M. "The mystery of declining tooth decay" Nature 322
Large temporal reductions in tooth decay, which cannot be
attributed to fluoridation, have been observed in both
unfluoridated and fluoridated areas of at least eight
developed countries over the past thirty years. It is now
time for a scientific re-examination of the alleged enormous
benefits of fluoridation.
Mark Diesendorf, an applied mathmetician, expert in research
design, and health researcher at the Human Sciences Program at
Austrailian National University showed in this analysis that the
decline in dental decay in fluoridated areas has not
been greater than in non-fluoridated areas. He used 24 studies of
unfluoridated areas to prove this.
Diesendorf isn't the only expert to realize the fact that
fluoridation is not what lead to the improvement in dental health.
In the April 1988 issue of the Journal of the American Dental
Association, Stanley Heifetz of the NIDR wrote, "the current reported
decline in caries in the U.S. and other Western industrialized
countries has been observed in both fluoridated and nonfluoridated
communities, with percentage reductions in each community apparently
about the same."
There have been numerous studies that have measured improvement
in dental health in fluoridated areas. Soon after the publication of
these studies, press releases often hail the "enormous dental health
improvements due to fluoridation." Had the authors of these studies
compared the results to non-fluoridated areas and taken a large
sample size (as was done in the Diesendorf and Ziegelbecker studies),
there would show no significant improvements in dental health
compared to nonfluoridated areas.
The moral is to beware fluoridation studies that compare it
against nothing and don't account for other factors
such as diet. They are nothing more than glorified press releases.
- Teotia SPS, Teotia M. "Dental caries: a disorder of high
fluoride and low dietary calcium interactions" Fluoride 27
April, 1994 (page 61).
This was a 20-year study (1973-1993) of 400,000 children in India.
It shows that the higher the fluoride concentration in water,
the more caries occured. In addition, this study shows that
adolescents ingesting fluoridated water and a low calcium diet have
extremely high rates of fluorosis and dental decay.
- Imai Y. "Study of the relationship between fluoride ions in
drinking water and dental caries in Japan" Japanese Journal of
Dental Health 22 144-196 1972.
This study of 22,000 Japanese schoolchildren showed that above
0.4 ppm the decay rate increased significantly.
When the fluoride concentration was below 0.2 ppm the decay rate
also increased significantly. This was thought to be caused by
the lack of calcium in the water when the fluoride was less than
Needless to say, Japan, like the large majority of countries
(including industrialized countries) does not fluoridate their water
8) Colquhoun, J. "Is There a Dental Benefit From Water Fluoride?"
Fluoride Vol. 27, No. 1 13-22, 1994.
Dental data collected for virtually all New Zealand children, as
well as comprehensive data from other countries, indicate no dental
benefit from water fluoridation. Claims for a benefit depend on
small-scale studies of selected samples of children. The classic
fluoridation research is critically re-examined.
This study, like the Yiamouyiannis study of 39, 207 US
schoolchildren, proves that fluoridation in New Zealand was and
is worthless. The data was collected for 98% of all 12-13
year-old children and 5 year-old children in New Zealand.
Here is the table from the study showing the main population
---------------------- 12-13 year olds -------- 5 year olds ------
This must-read study/report goes on to show the major flaws in so
many pro-fluoridation studies. Some notable excerpts:
"The New Zealand Department of Health, a long-time advocate of
water fluoridation, presented the 12-13-year-old data in its annual
reports by comparing the combined fluoridated with the combined
nonfluoridated areas of New Zealand [Annual Reports, Department of
Health, from 1981]. The differences were very small (only 1% for
the caries-free percentage in each kind of area, and less than half a
tooth for the mean number of decayed, missing or filled teeth) but
suggested a small benefit from fluoridation. However, the areas
being compared were dissimilar, one being mostly urban with higher
average incomes, and the other mostly small-town-rural with lower
average incomes. When similar kinds of communities were compared,
the teeth were actually slightly better in the nonfluoridated
"Other New Zealand studies, of small samples of 5-year-olds
7-year olds and 9-year-olds claimed that there was a small but
significant benefit resulting from fluoridation. These studies,
which were contradicted by the data collected for all 12- and
13-year-olds, were discussed in my earlier study.... Since then,
the authors of the 9-year olds study and its follow-up have
admitted that their low-fluoride sample used for comparison
'probably was biassed towards children of dentally unaware and
low socioeconomic parents -- a factor that would tend to increase
their caries.'" [See full text for references.]
"Recently another small-sample non-blind study has been
published, claiming to demonstrate the benefit of fluoridation for
the whold of New Zealand [New Zealand Dental Journal 88 9-13 1992].
Samll samples of 5-year-old children were examined, from selected
fluoridated and non-fluoridated communities in otago and cantebury
provinces. The results claimed up to 60% less tooth decay in the
fluoridated communities.... But, when I obtained the School Dental
Service data for all 5-year-olds in the fluoridated and
nonfluoridated areas of these two provinces...the claimed differences
did not exist." [The authors of the study had simply chosen the worst
nonfluoridated city to compare again on best fluoridated cities.]
He goes on to examine the history of fluoridation research which
is full of flawed studies beginning with HT Dean's studies in the
1930s and 1940s. Any student of dental science should read this
- Ray SK, Ghosh S, Tiwari TC et all. "An Epidemiological study of
caries and its relationship to fluoride content of drinking water
in rural communities near Varanasi" Indian Journal of Preventive
and Social Medicine 12 154-158 1981.
- "Fluoridation of Water", Chemical and Engineering News, 8/1/88
"Alan S. Gray, former director of the Division of Dental Health
Services for the British Columbia Ministry of Health, finds, for
example, that the average number of decayed, missing, and filled
permanent teeth in British Columbia, where only 11% of the population
uses fluoridated water, is lower than in parts of Canada where 40 to 70%
of the people drink fluoridated water. School districts in the
province with the highest percentage of children with no tooth decay
are totally unfluoridated. [See Gray, AS J. Canadian Dent.
Assoc. 53:763 (1987).]
- Caries incidence in children with 2.0-3.5 ppm fluuoride in water is
the same as that found in 0.20 ppm areas in Tanzania according to
several studies. See Community Dental Oral Epidemiology, Volume 14,
page 94-98 and page 99-103 and Scandinavian Journal of Dental
Research, Volume 96, page 385-389.
- There are many other studies which show that fluoridation does
not and has never prevented dental decay. Please see the
fluoride web page for a listing of other studies.
One other method that is used to make it appear that fluoridation
is useful are "defluoridation" studies. When fluoride is removed
from the water supply, some studies appear to show a large increase
in DMFT rate a few years later. What is usually not said is that
the increase is due almost completely to a change in dental practices
such that the decay part of DMFT (decayed, missing, filled teeth)
does not increase at all. Also, some of the studies are
conducted on young children (i.e., five year-olds) and we would
expect an increase in decay rate for that age group since tooth
eruption is no longer delayed by fluoridation.
In addition, pro-fluoridationists sometimes refer to fairly recent
small studies purporting to show decreases in DMFS or DMFT. This
is irrelevant. It is relatively easy for some researchers to select
areas where they know they will get the results they're looking for.
As you can see from the above-mentioned extremely large-scale studies,
there is no decrease in DMFT, but possible an increase. There
are no recent, large-scale studies (i.e., 1985-1995) which show a decrease
in DMFT rates other than the Brunelle studies which are discussed above.
Portland, Oregon rejected fluoridation not long ago. Albany,
New York rejected fluoridation recently. Several cities
and towns have thrown out fluoridation over the last few years.
To conclude, I'll quote Virginia Rosenbaum in an article
entitled "U.S. EPA Scientists Warns Nation of Hip Fractures in
Elderly Caused By Fluoride"
"Fluoridation will be banned in this country. It is in its death
throes now. It just hasn't stopped kicking! Like a snake, it keeps
twitching for awhile!"
There are numerous studies showing detrimental effect from
fluoridation (not only cancer and hip fractures), but you won't find
those studies listed in any ADA or EPA reviews.