Fluorine

Tal Kaplan3313

Source of fluorineFluorine 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 sourceFor the human organism fluorine source are of Natural sources :• Seafood.• tea.• fluoridated drinking water.• Soda.• Fish.

Metabolism & Toxicity Of FluorideOral 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.

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).

Mechanism Of Fluorine In Dental TissueDental 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.

Water FluoridationWater 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.

Fluoride level's

Age AI

0-6 months 0.01 mg/day

7-12 months 0.50 mg/day

Infant's:

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

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

Thank You For The Attention

Tal Kaplan3313