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 0.2 ppm.
Needless to say, Japan, like the large majority of
countries (including industrialized countries) does not
fluoridate their water supply.
8) Colquhoun, J. "Is There a Dental Benefit From
Water Fluoride?" Fluoride Vol. 27, No. 1 13-22,
1994.
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 centers.
Table
---------------------- 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 areas."
....
"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 review.