Trace element : Fluorine

Fluorosis is the most common cause of dental caries in children [Ref: Park 20/e, p 558 (19/e, p 511)]

Dental caries is not caused by fluorosis, but by fluorine deficiency. Moreever most common cause of dental caries in children is poor oral hygiene.

Endemic Fluorosis

• Endemic fluorosis occurs when drinking water contains increased amounts of fluorine (3-5 mg/L)
• Various toxic manifestations of endemic fluorosis are:

a. Dental fluorosis

– 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 molting 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.

– Mottling is almost entirely confined to the permanent teeth and develops only during the period of formation.

b. Skeletal fluorosis

– Chronic ingestion of excessive amount of fluorine (3.0 to 6.0 mg/L or more) results in skeletal fluorosis.

– There is a heavy fluoride deposition in the skeleton.

– Fluoride deposition leads to Osteosclerosis & calcification of the ligaments.

In the early clinical stage of skeletal fluorosis, symptoms include pains in the bones and joints; sensations of burning, pricking, and tingling in the limbs; muscle weakness; chronic fatigue; and gastrointestinal disorders and reduced appetite.

– In the next clinical stage, pains in the bones become constant and some of the ligaments begin to calcify. Osteoporosis may occur in the long bones, and early symptoms of osteosclerosis are present. Stiffness in the back occurs, especially in the lumbar region, followed by dorsal and cervical spines.

– Restriction of the spine movements is the earliest clinical sign of fluorosis. The stiffness increases steadily until the entire spine becomes one continuous column of bone manifesting a condition referred to as ‘poker back’.

– The stiffness that first appears in the spine soon spreads to various joints in the limbs owing to the involvement of the joint capsules, the related ligaments, and the tendinous attachments to the bones.

– The involvement of the ribs gradually reduces the movement of the chest during breathing, which finally becomes mainly abdominal. When that happens the chest assumes a barrel shape. With the increasing immobilization of the joints due to contractures, flexion deformities may develop at hips, knees and other joints, which make the patient bedridden.

– Despite the fact that the entire bone structure has become affected, the mental faculties remain unimpaired till the last stage is reached.

– The stage at which skeletal fluorosis becomes crippling usually occurs between 30 and 50 years of age in the endemic regions

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

a)Changing of water source

– Running surface water contains lower quantities of fluoride than ground water.

b)Chemical treatment

– Water can be chemically defluoridated in a water treatment plant.

– The National Environmental Engineering Research Institute, Nagpur has developed a technique for renewing fluoride by chemical treatment. Ida Nalgonda technique. It involves the addition of two chemical (viz lime and alum) in sequence followed by flocculation, sedimentation and filteration.

c)Other measures

– Fluoride toothpastes are not recommended for children in areas of endemic fluorosis.

– Fluoride supplements should not be prescribed for children who drink fluorinated water.

Enolase

1.0

The presence of fluoride reduces the solubility of enamel by promoting the precipitation of hydroxyapatite and phosphate mineral.

Ca10(P04)6(OH)2 +2F- ->   Ca10(PO4)6F2 + 2OH (OH ions are replaced)
(hydroxy-apatite)   (fluro-apatite)

Ref: Essentials of Pedodontics By Tilakraj, Pages 182-3 ; A Textbook of Public Health Dentistry By Marya, Page 348

Confirmed case of fluorosis is defined as presence of one or both of the following:

• High level of fluoride in urine >1mg/L
• Intraosseous membrane calcification in fore arm confirmed by Xray

Fluoride excess causes direct injury to ameloblasts, leading to inadequate production of tooth enamel. The resultant defect in enamel production causes recessed and discolored rings on the emerging teeth. Other conditions that cause enamel hypoplasia include inadequate levels of calcium, phosphorus, and vitamins A, C, or D, hypothyroidism, and hypoparathyroidism.

For blood glucose estimation in the laboratory, fluoride is added to the blood to prevent glycolysis by cells by inhibiting enzyme enolase so that blood glucose is correctly estimated.

Ref: Harper’s Principles of Internal Medicine, 26th Edition, Page 137; Textbook of Biochemistry By Vasudevan, 5th Edition, Pages 58, 87

Enolase is inhibited by fluoride, and when blood samples are taken for measurement of glucose, it is collected in tubes containing fluoride to inhibit glycolysis. 

C i.e. Enolase

For blood glucose estimation in the laboratory, fluoride is added to the blood to prevent glycolysis by the cells by inhibiting ‘enolase’ so that blood glucose is correctly estimated.Q.

D i.e. Fluoride

C i.e. Alcohol

Sodium fluride should be added to urine or vitrous humor, if alcohol estimationQ is required; and also to samples for analysis for cocaine, cyanides & CO.

Ans. is ‘a’ i.e., Conversion of hydroxy-apatite to fluro-apatite by replacing the OH ions

When hydroxyapetite is exposed to low fluoride concentrations (about 1 ppm) a layer offluorapetite forms on the hydroxyapetite crystals. The thin layer governs the rate of enamel dissolutin and reduces rate of caries progression. o During caries attack, the enamel is exposed to a pH of about 5.5 or lower, thereby leading to its dissolution.

o The presence of fluoride reduces the solubility of enamel by promoting the precipitation of hydroxyapetite and phosphate mineral.

C i.e. Isoflurane 

Isoflurane has least & methoxyflurane has highest fluride contentQ. Methoxyflurane causes vasopressin resistant high output renal failure.Q.

Ans. is ‘b’ i.e., Flourine

Flourine is often called a two edged sword : –

i) Excess intake      Causes Endemic fluorosis

ii)Inadequate        Causes dental caries

Ans. is ‘a’ i.e. Fluorosis is the most common cause of dental caries in children endemic Fluorosis

o Endemic fluorosis occurs when drinking water contains increased amounts of fluorine (3-5 mg/L)

o Various toxic manifestations of endemic fluorosis are:

a. Dental fluorosis

         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)

q          Earliest signs of dental fluorosis is molting 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.

         Mottling is almost entirely confined to the permanent teeth and develops only during the period of formation.

b. Skeletal fluorosis

          Chronic ingestion of excessive amount of fluorine (3.0 to 6.0 mg/L or more) results in skeletal fluorosis.

         There is a heavy fluoride deposition in the skeleton.

         Fluoride deposition leads to Osteosclerosis & calcification of the ligaments.

In the early clinical stage of skeletal fluorosis, symptoms include pains in the bones and joints; sensations of burning. pricking. and tingling in the limbs; muscle weakness; chronic fatigue: and gastrointestinal disorders and reduced appetite.

               In the next clinical stage, pain in the bones become constant and some of the ligaments begin to calcify. Osteoporosis may occur in the long bones, and early symptoms of osteosclerosis are present. Stiffness In the back occurs, especially in the lumbar region, followed by dorsal and cervical spines.

                 Restriction of the spine movements is the earliest clinical sign of fluorosis. The stiffness increases steadily until the entire spine becomes one continuous column of bone manifesting a condition referred to as ‘poker hack’.

• The stiffness that first appears in the spine soon spreads to various joints in the limbs owing to the involvement of the joint capsules, the related ligaments, and the tendinous attachments to the bones.
• The involvement of the ribs gradually reduces the movement of the chest during breathing. which finally

becomes mainly abdominal. When that happens the chest assumes a barrel shape. With the increasing

immobilization of the joints due to contractures, flexion deformities may develop at hips, knees and other

joints, which make the patient bedridden.

                 Despite the fact that the entire bone structure has become affected, the mental faculties remain unimpaired till the last stage is reached.

la The stage at which skeletal fluorosis becomes crippling usually occurs between 30 and 50 years of age in the endemic regions

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 (jov*ar). It was found that diets based on sorghum promoted a higher retention of ingested fluoride than do diets based on rice.

Ans. is ‘b’ i.e., Fluoride 

Maldon teeth refers to staining or motteling of teeth due to excessive fluoride in ground water, was observed in Maldon, essex. United kingdom.

Ans. is ‘d’ i.e., 0.5 

o The recommended level of fluorides in drinking water to prevent caries is 0.5-0.8 mg/L.

o But maximum permissible limit is 15 ing/L.

Ans. C: Fluoride

The vitreous humor specimen is particularly useful for alcohols, or in diabetes and insulin related deaths. It is also very useful where the body has decomposed. The fluid in the eye resists putrefaction longer than other body fluids as it is sterile and remains well protected in eye. It is useful for certain biochemical tests such as urea, creatinie, glucose, lactose and alcohol. Vitreous humor must be collected from both eyes in separate vials of 10 ml. It is preserved with sodium fluoride (10 mg/ m1).

Ans. Sodium fluoride

Ans. Fluoride

Ans. Prevent glycolysis

Ans. is ‘b’ i.e., Dentition

Ans. is ‘b’ i.e., F5 mg/dl

Fluorosis

• Fluorine is considered as ‘two edged sword’ because excess intake causes endemic fluorosis and inadequate intake causes dental caries.
• The recommended level of fluoride in drinking water is 0^.5 – 0^.8 mg/litre (PPM). But the recommended maximum permissible limit is 1.5 mg/litre.
• The major source of fluorine to man is drinking water.

Endemic fluorosis occurs when drinking water contains increased amount of fluorine :‑

1) Dental fluorosis

• It occurs during first 7 years of life (period of tooth calcification).
• It occurs at fluoride level > 1.5 mg/litre (PPM).
• Fluoride is deposited in enamel of teeth. Mottling is the earliest sign which affect upper incisors and is confined to permanent teeth.

2) 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.
• Recentally, a new form of fluorosis has been identified, which is characterized by genu valgum and osteoporosis of lower limbs. It occurs in people whose staple diet is Sorghum (jawar).

3) Crippling fluorosis

• This occurs at fluoride level > 10 mg/litre (PPM). Patient is crippled and bed ridden.
• Defluridation of water is done by Nalgonda technique, developed by National Environmental Engineering Research Institute (NEERI), Nagpur. It involves chemical treatment of water by lime and alum in sequence followed by flocculation, sedimentation and filteration.
• Household level defluridation can be done by : (i) Nalgonda technique, (ii) Alumina, and (iii) Phosphates.