Fluorides
PDS 372
• The story of fluoride
• Colorado Brown Stain
• Frederick McKay
• H. Trendley Dean, head of the Dental
Hygiene Unit at the National Institute of
...
• Desirable F concentration:
– The highest F concentration incapable of
producing a definite degree of mottled enamel
in a...
1945
• During the 15-year project, researchers
monitored the rate of tooth decay among
Grand Rapids' almost 30,000
schoolc...
Environmental Fluoride
•
•
•
•

Seawater 1.2-1.4 ppm
Fresh surface water 0.2
Deep well water 29.5 ppm
Over 40 ppm in boreh...
Sources and F intake
• 0.04 mg F/day from air
• 1~3 mgF for adult from diet and F-water
• Market basket study
– 0.21-0.54 ...
Fluoride physiology
Absorption, retention and excretion
•
•
•
•
•

Absorbed From Upper GIT (95%)
Transported in plasma
Exc...
• Body burden of fluoride: amount can be
safely absorbed, and at which F
absorption become a health concern
– Plasma conce...
• Plasma concentration
– Normal 0.019 ppm
– Chronic kidney failure 0.05-0.09 ppm
– Nephrotoxic 0.95 ppm

• Dynamic storage...
Fluoride toxicity
• Dose-response relationship
• 5 g F vs. 1-3 mg F daily (toxic vs. beneficial)
• Ingestion of single dos...
Fluoride and caries control
• Work best when there’s constant low level of
F in the oral cavity.
• Work post-eruptively, a...
• Fluoride and plaque:
– Promote remin.
– Partly taken up by plaque in bound form. And
released in response to lower pH an...
• Fluoride and saliva
– 0.016 ppm
– 0.006 ppm
– Its role in caries prevention is not well defined

• Effects on different ...
Fluoride, Human Health and Caries Prevention
Fluoride, Human Health and Caries Prevention
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Fluoride, Human Health and Caries Prevention

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Transcript of "Fluoride, Human Health and Caries Prevention"

  1. 1. Fluorides PDS 372
  2. 2. • The story of fluoride
  3. 3. • Colorado Brown Stain • Frederick McKay • H. Trendley Dean, head of the Dental Hygiene Unit at the National Institute of Health (NIH)
  4. 4. • Desirable F concentration: – The highest F concentration incapable of producing a definite degree of mottled enamel in as much as 10% of the group examined. • The permissible maximum : 1 ppm F
  5. 5. 1945 • During the 15-year project, researchers monitored the rate of tooth decay among Grand Rapids' almost 30,000 schoolchildren • After 11 years, the caries rate among Grand Rapids children born after fluoride was added to the water supply dropped more than 60 percent
  6. 6. Environmental Fluoride • • • • Seawater 1.2-1.4 ppm Fresh surface water 0.2 Deep well water 29.5 ppm Over 40 ppm in boreholes in Kenya
  7. 7. Sources and F intake • 0.04 mg F/day from air • 1~3 mgF for adult from diet and F-water • Market basket study – 0.21-0.54 mg F/day (infants 6 months old) – 0.41-0.61 mg F/day (2 years old) • For a 12-months child, the upper limit of intake beyond which fluorosis risk is greatly increased: 0.43 mg Fday • F content of food vary. Table 24-1
  8. 8. Fluoride physiology Absorption, retention and excretion • • • • • Absorbed From Upper GIT (95%) Transported in plasma Excreted or deposited in the calcified tissue 5 mg F excreted in 8-9 hours Plasma level of F increase w empty stomach
  9. 9. • Body burden of fluoride: amount can be safely absorbed, and at which F absorption become a health concern – Plasma concentration • Ionic: fluctuated, see next slide • Nonionic: the biologic significance is not dtermined – Urinary excretion • F balance: net result from the accumulated effect of F ingestion, degree of F deposition in bone and teeth, mobilization rate of F from bone, efficiency of the kidney in clearing absorbed F.
  10. 10. • Plasma concentration – Normal 0.019 ppm – Chronic kidney failure 0.05-0.09 ppm – Nephrotoxic 0.95 ppm • Dynamic storage • F has affinity to calcified tissues • Optimal fluoride intake – Frank McClure (1943) 1-1.5 mg F – 0.05-0.07 mg F/Kg per day
  11. 11. Fluoride toxicity • Dose-response relationship • 5 g F vs. 1-3 mg F daily (toxic vs. beneficial) • Ingestion of single dose of 5~10 g of NaF by adult male cause death in 2~4h • Classic F toxicity study in Denmark 1930s: – Gastric complications and osteosclerosis. • Dental Fluorosis: – Permanent hypomineralization of the enamel, with surface or subsurface porosity, due to exposure of excess fluoride during tooth maturation stage
  12. 12. Fluoride and caries control • Work best when there’s constant low level of F in the oral cavity. • Work post-eruptively, at tooth plaque interface • Mechanism of action – Preeruptive: reduction of enamel solubility in acids – Posteruptive: *promote remin-. and inhibit demin-. Of early lesion. *inhibit Glycolysis of carbs.
  13. 13. • Fluoride and plaque: – Promote remin. – Partly taken up by plaque in bound form. And released in response to lower pH and taken up by demin enamel. – F in plaque inhibit the glycolysis – Interfere with plaque adherence to enamel – Specific bactericidal on cariogenic bacteria • Fluoride and enamel – Teil-Culemborg study: fewer enamel lesions extends to dentinal caries in fluoridated areas than in non-fluoridated area – F inhibit further demin and promote remin
  14. 14. • Fluoride and saliva – 0.016 ppm – 0.006 ppm – Its role in caries prevention is not well defined • Effects on different tooth surfaces – Murray’s study: More reduction on smooth surface caries. • Effective use of fluorides – Systemic fluorides – Topical fluorides

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