* Fluorine sources * Metabolism & Toxicity Of Fluoride * Mechanism Of Fluorine In Dental Tissue * Water Fluoridation * Fluoride level's

1. Fluorine
Tal Kaplan
3313

2. Source of fluorine
Fluorine is a chemical element with the symbol F and atomic number 9.
It is the lightest halogen and exists as a highly toxic pale yellow
diatomic gas at standart condition.
Elemental fluorine in Earth's atmosphere would easily react with rocks,
precluding its natural occurrence; it is found only in combined mineral
forms, of which flurite, fluorapetite and cryolite are the most
industrially significant. Fluorite or fluorspar (CaF2), colorful and
abundant worldwide, is fluorine's main source
For the human organism fluorine source are of Natural sources :
• Seafood.
• tea.
• fluoridated drinking water.
• Soda.
• Fish.

3. Metabolism & Toxicity Of Fluoride
Oral uptake:
In humans and animals, ingested fluoride occurs as hydrogen fluoride (HF) in the acidic
environment of the stomach and is effectively absorbed from the gastrointestinal tract,
although there is no proved absorption from the oral cavity. Highly soluble
fluoride compounds, such as NaF present in tablets, aqueous solutions and toothpaste
are almost completely absorbed, whereas compounds with lower solubility, such as
CaF2, MgF2, and AlF3, are less well absorbed.
Dermal absorption:
No experimental data on the extent of dermal absorption of fluoride from dilute
aqueous solutions are available (like in shower).
Inhalation:
No systematic experimental data on the absorption of fluoride after inhalation are
available.
Once absorbed, fluoride is rapidly distributed throughout the body via the blood.
The short term plasma half-life is normally in the range of 3 to 10 hours. fluoride is
distributed between the plasma and blood cells, with plasma levels being twice as high
as blood cell levels. fluoride concentrations are not homeostatically regulated, but rise
and fall according to the pattern of fluoride intake.

4. Approximately 99% of the fluoride in the human body is found in bones and
teeth. fluoride is incorporated into tooth and bone by replacing the hydroxyl ion in
hydroxyapatite to form fluorohydroxyapatite. The level of fluoride in bone is
influenced by several factors including age, past and present fluoride intake, and
the rate of bone turnover. fluoride is not irreversibly bound to bone and is mobilized
from bone through bone remodelling.
Soft tissues do not accumulate fluoride, but a higher concentration has been
reported for the kidney due to the partial re-absorption. The blood-brain barrier
limits the diffusion of fluoride into the central nervous system, where
the fluoride level is only about 20% that of plasma. Human studies have shown that
fluoride is transferred across the placenta, and there is a direct relationship
between fluoride levels in maternal and cord blood.
Ingestion of high concentration fluoride can produce gastrointestinal discomfort at
doses at least 15 to 20 times lower (0.2–0.3 mg/kg) than lethal doses. Although
helpful for dental health in low dosage, chronic exposure to fluoride in large
amounts interferes with bone formation. In this way, the greatest examples of
fluoride poisoning arise from fluoride-rich ground water, that can cause fluorosis
(developmental disturbance of dental enamel changes of tooth color – brown).

5. Mechanism Of Fluorine In Dental Tissue
Dental fluorosis (DF) is an undesirable developmental defect of tooth
enamel attributed to greater-than-optimal systemic fluoride exposure
during critical periods of amelogenesis. DF is characterized by increased
porosity (subsurface hypomineralization) with a loss of enamel
translucency and increased opacity. Ameloblasts in the maturational phase
appear to be the cellular target of chronic fluoride exposure (DenBesten
and Thariani, 1992), whereas acute fluoride toxicity targets the transitional
and early-secretory ameloblasts. The mechanism(s) underlying DF remain
obscure, but likely contribute to the observed retention of enamel matrix
proteins and may include reduced removal of enamel matrix proteins
during enamel maturation, perturbation of extracellular transport, or
initiation of the ER stress-response pathway.

6. Water Fluoridation
Water fluoridation is the controlled addition of fluoride to a public water supply to
reduce tooth decay. Fluoridated water has fluoride at a level that is effective for
preventing cavities; this can occur naturally or by adding fluoride. Fluoridated water
operates on tooth surfaces: in the mouth it creates low levels of fluoride in saliva,
which reduces the rate at which tooth enamel demineralizes and increases the rate at
which it remineralizes in the early stages of cavities.
Effectiveness:
Water fluoridation effectively reduces cavities in both children and adults:[9] earlier
studies showed that water fluoridation reduced childhood cavities by fifty to sixty
percent, but more recent studies show lower reductions (18–40%) likely due to
increasing use of fluoride from other sources, notably toothpaste, and also the 'halo
effect' of food and drink that is made in fluoridated areas and consumed in
unfluoridated ones.

7. Fluoride level's
Infant's:
Age AI
0-6 months 0.01 mg/day
7-12 months 0.50 mg/day

8. Adult's
Age AI
Men
19-30 yr 4 mg/day
31-50 yr 4 mg/day
51-70 yr 4 mg/day
>70 yr 4 mg/day
Women
19-30 yr 3 mg/day
31-50 yr 3 mg/day
51-70 yr 3 mg/day
>70 yr 3 mg/day

9. Pragnancy:
Age AI
14-18 yr 3 mg/day
19-30 yr 3 mg/day
31-50 yr 3 mg/day
Lactation:
Age AI
14-18 yr 3 mg/day
19-30 yr 3 mg/day
31-50 yr 3 mg/day

10. Tal Kaplan
3313