Fluoride plays a vital role in preventing dental caries. It was introduced in dentistry over 70 years ago and has led to a large decrease in cavities in many countries due to water fluoridation programs. Fluoride works by being incorporated into tooth enamel during its development, making it more resistant to acids produced by bacteria. However, too much fluoride intake during tooth development can cause dental fluorosis. Water fluoridation, where fluoride is added to public water supplies, is considered one of the greatest public health achievements and is a safe and effective way to deliver fluoride on a large scale.

1. FLORIDATION : MECHANISM AND
EFFECTS
Lecture 10
Dr. noorah murad DDS

2. Fluorine and fluoride
Fluorine: symbol F
atomic no, 9, a chemical
element, electronegative,
naturally occurring,
Can not found in nature in its
natural form, highly toxic pale
yellow gas, extremely
reactive.
Fluorine is estimated to be the 13th most abundant element in earth’s
crust and is widely dispersed in nature almost entirely in the form of
fluoride .
Fluoride: chemical
formula F-, is the simplest
fluorine anion, whose salts are
typically white or colorless.
Occurs on earth in several
minerals particularly
fluorite, but are present
only in trace quantities in
natural water.

3. Fluoride crystal
Fluorite crystal

4. Fluoride role in dentistry
•Fluoride ion play a vital role in prevention of dental
caries,
•It was introduced in to dentistry over 70 years ago.
•The decrease in prevalence and severity of dental
caries over the second half of the 20th century in many
industrialized countries is attributed to the use of
fluorides.
•However excessive fluoride intake during the period of
tooth development can cause dental fluorosis.

5. Dental fluorosis (also termed: mottled enamel)
is an extremely common disorder, characterized
by hypo mineralization of tooth enamel caused
by ingestion of excessive fluoride during enamel
formation.

6. HISTORY
 Dr. Frederick McKay 1901: he noticed some of his patient in
Colorado springs have permanent stain on their teeth (mottled
enamel).
 Dr. McKay and Black 1916: conduct studies on individual in 26
communities in USA and concluded that (unidentified factor)
present in water was responsible for mottling of enamel.
 Dr. McKay found that these mottled enamel cases are free from
caries.
 Dean and co-workers conducted a survey on 21 cities to establish
the relationship between mottled enamel which replaced by the
term dental fluorosis and the level of fluoride in water supply.

7. Sources of fluoride
Groundwater, atmosphere, food, drugs and other products,
and pollution

8. Water fluoridation
It is the controlled addition of fluoride to
public water supply for optimal dental health
which effectively prevent caries and it is the
best method of delivering fluoride on a
population basis.
Community water fluoridation is safe and cost-effective and
should be introduced and maintained wherever it is socially
acceptable and feasible.

9. Water fluoridation consider
one of the “ten greatest
public health achievements
of the 20th century”

10. There are three forms of fluoride
that are used to fluoridate water
1. Sodium fluoride
2. Sodium fluorosilicate
3. Fluor silicic acid
The optimum level of fluoride in water varies
depending on the temperature and
geographic location (range 0.7 – 1.0 ppm)

11. Types of fluoride
The choice depend on :
1. Current levels of fluoride intake
2. Caries status
3. Age of subjects in the area
Types is either
Systemic fluoride or topical
fluoride

12. Systemic
For pre and post eruptive
phase
Topical
Post eruptive phase only
Types of fluoride
1. Communal water
fluoridation
2. Alternative methods for
C.W.F.
• School water fluoridation.
• Home water fluoridation.
• Fluoridated tablets.
• Fluoridated salts.
• Fluoridated milk.
 Dentifrices.
 Fluoridated mouth rinse.
 Fluoridated gel.
 Professional fluoride
application in the form of
solutions, gel, foam,
varnishes, prophylactic
paste or pumice and in the
form of many fluoridated
agent like NaF, SnF2

13. Metabolism of fluoride
Fluoride ingested -----> absorbed by
stomach -----> concentrated in blood
reaches peak after 30min ----> return to
usual level after 11-15 h -----> 99%
associated with calcified tissue -----> the
remain excreted via the kidney

14. Role of fluoride in caries
reduction
1. Decrease solubility of enamel in acid by converting
hydroxyapatite into less soluble Fluor hydroxyapatite /
Fluor apatite.
2. Enhance re mineralization of enamel in areas that have
been demineralization by acids.
3. Antibacterial action: bactericidal in high conc. And
bacteriostatic in low conc.
4. Improve tooth morphology making them more self
cleaning.

16. Ca10 (PO4)6(OH)2(s)+2F(aq) 2OH(aq)
+Ca10(PO4)6(F)2(s)
Ca10 (PO4)6(OH)2(s)+8H(aq) 10 Ca2+
+6(HPO4) 2-
+2H2O