fluoride

• Confer on the tooth a greater resistance to carious destruction when ingested systemically or topically applied.

  Fluoride
• Flouride in water


  fluoridation, systemic
• Topical Flouride 


  fluoridization
• fluoride is Absorbed into the plasma from the gastrointestinal tract
• is deposited in bone and developing teeth

  Plasma fluoride
• fluoride is Excreted in urine and to a lesser degree in sweat.
• Unabsorbed fluoride is lost in feces.
• Fluoride ions substitute hydroxyapatite crystals in enamel forming fluorapatite


  more resistant to acid dissolution:
• Hydroxyapatite is composed of

  calcium, phosphate and hydroxyl ions
• Fluoride ions act on: o Cariogenic bacteria by inhibiting glycolysis → fermentation of sugars into acid
• Plaque colonization by suppressing salivary protein adsorption onto the enamel and by a direct antibacterial effect
• 2 critical periods for fluoride incorporation into the enamel surface

  Terminal stages of crown formation (development), Preeruptive maturation of the crown in the dental sac
• Antibacterial properties at low plaque pH through the formation of hydrofluoric acid → interferes with enzymes involved with glycolysis
• nhibits dissolution of calcium and phosphate in the enamel subsurface of an incipient carious lesion during an acid challenge (demineralization)
• Enhances remineralization by helping calciumphosphate precipitates at the enamel surface to recrystallize into a more acid-resistant surface.
• 2 methods 


  Systemic o Topical
• SYSTEMIC FLUORIDE THERAPY 


  Water fluoridation • Supplemental fluoride therapy
• Dental fluorosis or "motled enamel" was found to be the result of defective enamel calcification caused by excessive amounts of fluoride in the drinking water.


  1931
• Unacceptable cosmetically → beneficial effects in terms of a lower caries prevalence.


  1931
• Teeth formed in the presence of 1 ppm of fluoride in drinking water exhibited fewer caries with no clinical signs of dental fluorosis
• With increasing concentration, fluorosis increased in prevalence without a proportional decrease in caries prevalence
• caries reduction from continuous exposure to optimally fluoridated water since birth

  50-70%
• caries reduction when fluoride therapy is instituted at 6 years of age


  20-45%
• optimal Cold climate


  1-ppm - 1.2 ppm
• Warmer climates 


  0.7 ppm
• Commonly used compounds for communal water fluoridation:

  Sodium fluoride o Hydrofluosilic acid o Sodium silicofluoride
• Anterior teeth receive greater protection than the posterior teeth
• For fluoride-deficient areas


  SUPPLEMENTAL FLUORIDE THERAPY
• Similar benefits as those derived from consuming optimally fluoridated water when given conscientiously

  SUPPLEMENTAL FLUORIDE THERAPY
• Limitations of supplemental:

  o Cost o Inconvenience o Patient compliance and reliance
• Prenatal fluoride therapy • Rationale:

  fluoride crosses the placental barrier
• Not currently recommended that pregnant women ingest supplemental fluoride for the benefit of their unborn children
• Alternatives to community fluoridation during the postnatal period:

  At home fluoridator, In school fluoridators
• Fluoride level should be 4.5 times the normal


  n school fluoridators
• prescribe only if less than 60% of the recommended optimal fluoride concentration for that climatic area is found (0.6 mm for 1 ppm or 0.4 ppm for 0.7 ppm)


  Fluoride supplements
• Acute lethal dose:


  36 mg/kg of body weight.
• Common symptoms of acute toxicity:

  o Nausea o Vomiting o Hypersalivation o Abdominal pain
• TOPICAL FLUORIDE APPLICATION •

  Vehicles o Gels o Mouthrinses o Prophylaxis pastes o Dentifrices
• Supplement not substitute to systemic fluoride therapy

  TOPICAL FLUORIDE APPLICATION
• Optimal benefits if used in a multipleregimen approach of frequent applications over a prolonged due to additive or cumulative action of fluoride on the enamel

  TOPICAL FLUORIDE APPLICATIOn