Fluoride was discovered in the 19th century through research on teeth and bones. Early studies found fewer dental caries in areas with natural water fluoride. The first trials adding fluoride to water in the 1940s significantly reduced tooth decay. While effective, fluoridation remains controversial with some concerned about health effects and individual rights. However, extensive research has consistently shown water fluoridation to be safe and effective for preventing tooth decay.

1. Katrina Lazala
HUMSS 12-A
Fluorine

2. The discovery
of fluoride

3. Hearing of "fluorine" or "fluoride" most
people now think instantly of dentistry, of
dental caries or the different ways of fluoride
application to prevent that disorder. But
these terms are not inventions of dentistry,
nor was the use of fluorides originally in any
way related to that profession.

4. Fluoride Research in
the 19th and early
20th century

5. In the 19th century, research on fluoride
and its occurrence in teeth and bones was
carried out by physicians and chemists in
Europe while the dental profession was still
not organized as we know it today. The
analytical methods of the time were quite
limited and the results rather controversial.
Thus, the early recommendations to take
fluoride pills to prevent dental caries were
based on anything but sound science and -
then already- subject to heated debates...

6. • What it does:
-Helps developing enamel become strong,
resistant to decay
-Helps remineralize early defects in
enamel
-Retards growth of bacteria
Fluoride

7. 1) Do not harm the patient.
2) Prevent decay on intact dental
surfaces.
3) Arrest active decay.
4) Remineralize decalcified tooth
surfaces.
Goals of Fluoride

8. Initial discoveries :
• 1927 – Frederick McKay visited Resina (near
Naples) and found tooth mottling in adults but not in
young children - water supply recently changed
from wells sunk into lava from Mt Vesuvius
• 1928 – McKay investigated Bauxite, Arkansas
where mottling found, fluoride ion concentration of
13.7ppm

9. Fewer caries in areas of natural waterborne
fluoride :
• In South Dakota H. T. Dean found that the
dental caries rate was inversely proportional
to the prevalence of mottled enamel
• Dean then compared Galesburg, IL (fluoride
concentration 1.9 ppm) and Monmouth IL
(1.6 ppm) to Macomb and Quincy, IL (less
than 0.2 ppm)

10. Fewer caries in areas of natural waterborne
fluoride :
• In Galesburg and Monmouth about 35% of
12-14 year olds were caries free compared to
only 14% in Macomb and 4% in Quincy

11. Determining optimum levels of fluoride to
prevent caries and avoid fluorosis :
• 1942 – H. T. Dean reported on a survey of
7000 schoolchildren in 21 US cities and
concluded optimum concentration was 1.0
ppm; during the 1940s the US PHS began to
recommend fluoridation of water supplies at
this level

12. Determining optimum levels of fluoride to
prevent caries and avoid fluorosis :
• Galagan and others later decided optimum
concentration was dependent on the average
annual maximum daily air temperature and
varied from 0.7 – 1.2 ppm in the continental US
because people were thought to drink more
water in warmer climates

13. Large-scale trial to assess protective effects
of fluoride :
• 1945 – Newburgh-Kingston fluorine-caries trial
comparing the fluoridated town of Newburgh,
NY to neighboring un-fluoridated Kingston
• Both towns had populations around 30,000
with previously “fluoride deficient” water; in
May 1945 Newburgh began fluoridating at 1.0
ppm

14. Large-scale trial to assess protective effects
of fluoride :
• “Decayed, missing, filled” (DMF) rates used to
compare populations Annual dental
examinations performed on schoolchildren in
Newburgh & Kingston in each of the years
1944-1945 through 1954-1955

15. Newburgh-Kingston results: focus on 6-9
year olds, including first molars :
NEWBURGH-KINGSTON CARIES-FLUORINE
STUDY VOL. 46 269
Table 3-Number and Per Cent of Children Age 6-
9 with Caries-Free Deciduous Cuspids, First and
Second Deciduous Molars, Based on Clinical
and Roentgenographic Examinations, Kingston
and Newburgh,* N. Y.,1954-1955

16. Newburgh-Kingston results: focus on 6-9
year olds, including first molars :

17. Etiology of caries :
• Cariogenic bacteria in dental plaque
metabolize a substrate from the diet (e.g.,
sugars and other fermentable carbohydrates)
and the acid produced as a metabolic by-
product de-mineralizes (i.e., begins to
dissolve) the adjacent enamel crystal surface
• Demineralization involves the loss of calcium,
phosphate, and carbonate.

18. Etiology of caries :
• Fluoride, when present in the mouth, is also
retained and concentrated in plaque

19. Mechanism of action of fluoride in prevention of caries :
• As cariogenic bacteria metabolize carbohydrates and
produce acid, fluoride is released from dental plaque in
response to lowered pH at the tooth-plaque interface
• The released fluoride and the fluoride present in saliva
are then taken up, along with calcium and phosphate,
by de-mineralized enamel to establish an improved
enamel crystal structure which is more acid resistant
and contains more fluoride and less carbonate

20. Controversy begins: Wisconsin :
• 1946 – Sheboygan, WI fluoridates municipal water
• 1948 – Favorable results announced, 4 prominent
dentists promote fluoridation statewide
• 1950 – Fluoridation defeated by referendum in
Stevens Point, WI
• Stevens Point opponents stated fluoridation is:
-ineffective in reducing dental caries
-basically harmful to the human system
-deprives individuals of free choice because it
forces them to accept medication against their will

21. How does water fluoridation compare to
other public health measures? :
• To protect public health we:
• add folic acid to cereal products to
prevent birth defects
• add iodide to salt to prevent goiter
• add chlorine to water to disinfect it add
vitamin D to milk to build stronger bones

22. Other anti-fluoridation arguments :
• Communist plot (popular in cold-war era)
• US Government conspiracy; Manhattan
project used fluorine gas in atomic program,
several early fluoridation proponents had
contacts with the Manhattan project
(popularized more recently)
• Adverse health effects

23. Hypotheses to explain anti-fluoridation impulse :
• 1955 – analysis of opinion poll taken during
anti-fluoridation referendum showed anti-
fluoridationist arguments are:
-simple and easy to follow
- based on widely held cultural mores
(individual rights, fear of the unknown, fear
of poison, & fear of bodily harm)
- based on the tendency to perceive the
world as menacing

24. Fluoride in Maine – Norway study :
• October 1952 – Norway, ME began
fluoridation at 1.0 ppm with inspection of
teeth of all elementary school children
• Follow-up inspections were done in April
1955 with the following results:

25. Fluoride in Maine – Norway study :

26. Fluoride in Maine (cont’d) :
• Between 1996-2004 several local
referenda passed authorizing community
water systems to fluoridate –> 29
communities gained access to fluoridated
water
• Maine law requires that each city or
town decide through referendum whether
it wants fluoride in the water

27. Fluoride in Maine - today :
• 63 public water systems provide fluoridated
water to 133 communities throughout the state
• Population served is about 80% of people who
get their water from public systems, which
translates to about 38% of the total population,
since just under half of Maine people get their
drinking water from public water supplies

28. Challenges to Fluoride in Maine :
• Bangor and Mount Desert - in March 2007 a
Bangor pediatrician called for discontinuing
fluoridation - Bangor City Council held a series
of reviews and meetings, concluding no need
for a referendum, but Town of Mt. Desert voted
in a town meeting to stop fluoridating in
Northeast Harbor and Seal Harbor; this activity
was led by the water district’s chief operator.
•

29. Challenges to Fluoride in Maine :
• Jackman and Moose River voted in 2008 to
discontinue fluoridation of the Jackman Utilities
District, water district employees involved
• Vinalhaven – Fluoridation approved in
November 2008, but then rejected in a revote
in June 2009 with a much smaller turnout

30. Challenges to Fluoride in Maine :
• Portland - Early last summer, a petition drive to collect
signatures to put a referendum on the ballot in the
communities served by the Portland Water District
was unsuccessful
• Island Falls – in September 2009 stopping fluoridation
was proposed as a budget issue, but then retained
after area dental professionals focused on the cost
effectiveness of fluoridation as a preventive
intervention

31. Any link between Fluoride and
osteosarcoma? :
• A population-based CC study in NYS, excluding
NYC. 130 subjects diagnosed with
osteosarcoma between 1978 and 1988, at age
24 years or younger Study tested the
hypothesis that fluoride exposure in a non-
occupational setting is a risk factor for childhood
osteosarcoma.

32. Any link between Fluoride and
osteosarcoma? :
• RESULTS. Total lifetime fluoride exposure was
not significantly associated with osteosarcoma
among all subjects combined or among
females. However, a significant protective trend
was observed among males.

33. Any link between Fluoride and
osteosarcoma? :
• CONCLUSIONS. Fluoride exposure does not
increase the risk of osteosarcoma and may be
protective in males. The protective effect may
not be directly due to fluoride exposure but to
other factors associated with good dental
hygiene.

34. The End