Trace element : Fluorine

  • Fluorine is often called a two edged sword : -
  • Excess intake causes Endemic fluorosis and Inadequate intake causes dental caries.
  • As per WHO, permissible limit of fluoride in drinking water is 1.5 mg/ litre. As per Bureau of Indian Standards (BIS), it is 1 mg/ litre. .
  • Topical fluoride reduces dental caries.:The presence of fluoride reduces the solubility of enamel by promoting the precipitation of hydroxyapatite and phosphate mineral.
  • Fluoride, used in the collection of blood samples for glucose estimation, inhibits the enzyme Enolase.(Sodium Fluoride is added to prevent Glycolysis)
  • Fluoride should be added to urine, CSF, and vitreous humour if alcohol estimation is required, and also to samples for analysis for cocaine, cyanide and CO.
  • Endemic fluorosis occurs when drinking water contains increased amounts of fluorine (3-5 mg/L).
  • Confirmed case of fluorosis is defined as presence of one or both of the following:
  1. High level of fluoride in urine >1mg/L
  2. Intraosseous membrane calcification in forearm confirmed by Xray.
Various toxic manifestations of endemic fluorosis are:
a. Dental fluorosis.
  • Dental fluorosis has been reported with exposure to levels > 1.5 mg/ litre.
  • Fluoride is deposited in the enamel of teeth when excess fluoride is ingested during the years of tooth calcification (i.e. during the first 7 yrs of life)
  • Earliest signs of dental fluorosis is mottling of dental enamel. The teeth loose their shine and chalk white patches develop. Later the white patches turn yellow or sometimes brown or black. In severe cases, loss of enamel gives the teeth a corroded appearance.
  • Mottling is best seen on the upper incisors.
  • Maldon teeth refers to staining or motteling of teeth due to excessive fluoride in ground water
b. Skeletal fluorosis
  • It occurs at fluride level 3-6 mg/litre.
  • Fluoride is deposited in bones. There is osteosclerosis, calcification of ligaments, back stifness with restriction of spine movements (earliest sign), and flexion deformities of joint.
  • There is no impairment of mental faculties.
c. Genu valgum
  • In recent years, a new form of fluorosis characterised by genu valgum and osteoporosis of the lower limbs has been reported from some districts of Andhra Pradesh and Tamil Nadu.
  • This form of fluorosis was observed in people whose staple diet was Sorghum (jowar). It was found that diets based on sorghum promoted a higher retention of ingested fluoride than do diets based on rice.
Interventions to prevent fluorosis
  • Changing of water source
  1. Running surface water contains lower quantities of fluoride than ground water.
  • Chemical treatment
  1. Water can be chemically defluoridated in a water treatment plant.
  2. The National Environmental Engineering Research Institute, Nagpur has developed a technique for renewing fluoride by chemical treatment. It is Nalgonda technique. It involves the addition of two chemical (viz lime and alum) in sequence followed by flocculation, sedimentation and filteration.
  • Other measures
  1. Fluoride toothpastes are not recommended for children in areas of endemic fluorosis.
  2. Fluoride supplements should not be prescribed for children who drink fluorinated water.
Exam Question of:
  • The clinical manifestations of Fluorosis are fluoride deposition in bones,teeth,Genu Valgum.
  • Defluoridation is done by Nalgonda technique.
  • Fluoride, used in the collection of blood samples for glucose estimation, inhibits the enzyme Enolase.
  • Maximum permitted level of fluoride in drinking water is 1 meq/L.
  • "Maidon Teeth" is due to Fluoride .
  • The primary mechanism of action of fluoride on topical application is as follows: Conversion of hydroxyapatite to fluorapatite by replacing the OH- ions.
  • In a case of suspected poisoning, the preservative used for vitreous during autopsy is Fluoride.
  • Confirmed case of fluorosis is defined by presence of fluoride in urine more than 1 mg/L.
  • Permissible level of fluoride in drinking water as per WHO is 1.5 mg/litre.
  • Mottled enamel will be the earliest manifestation of fluorosis in a child.
  • Excessive levels of Fluoride may have produced the defect in an 8 month old female child presenting with her first four teeth showing several discrete, discolored, circumferential bands that show very little enamel.
  • In a PHC, Potassium oxalate + sodium fluoride anticoagulant is used to sent the blood sample for blood glucose estimation .
  • Sodium fluoride may be used for preservation of Alcohol.
  • Double edged sword is Fluorine. Recommended level of fluoride to be present in water to prevent caries is 0.5-0.8 mg/L..
  • Fluoride helps in Dentition.
  • Dental fluorosis occurs if fluoride level is more than 1-5 mg/dl.

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