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16 Cards in this Set
- Front
- Back
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Define demin and remin
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-Tooth surface constantly undergoing remin/demin
-In an acid environment the mineral content (hydoxyapatite) is dissolved out of the tooth -pH is lower than 5.5 -As acidic levels return to neutral, remin occurs -pH 7 |
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What is the critical pH level?
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the point where equilibruim exists eg: no mineral dissolution and no mineral precipitation
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What is the critical pH of hydroxyapatite?
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5.5
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What is the critical pH of flurapatite?
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4.5
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During remineralisation, what would the tooth prefer? Fluoride or calcium?
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Fluoride, fluorapatite is formed rather than calcium apatite.
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Where does most of plaque Fluoride come from?
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Topical sources
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Name some topical sources?
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-fluoridated water
-Toothpaste -food and drink -fluorides applied in clinics |
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Is fluoride concentration in plaque higher than in saliva?
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YES
Saliva 0.02ppm plaque 5-10ppm |
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Define Enamel maturation
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-Impurities are replaced with fluorapatite
-Same as normal remin demin - Acidulated phosphate fluoride usage |
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What are some implications of fluoride?
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-Only low levels should be present in the mouth constantly
- Water fluoridation is able to work as a topical agent -We need fluoride throughout life -Systemic supplements may not be effective |
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What happens when concentrated fluorides (above 100ppm) are used?
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- F reacts with Ca= calcium fluoride
-Coats the tooth surface -Reservoir of F to be released when the pH drops |
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What are the levels of F that will inhibit acid production?
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10ppm
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What are the levels of F that will inhibit growth of bacteria?
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100ppm
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What are the three principal mechanisms by which fluoride is considered to inhibit dental caries?
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1. promoting remin and inhibiting demin of early carious lesions
2. Inhibition of glycolysis 3. reduction in enamel solubility in acid by incorporating fluoride into hydoxyapatite crystal |
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How does fluoride inhibit bacterial enzyme systems?
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Reducing their metabolic activity and giving reduced acid production
Also fluoride reduces the tendency of enamel to absorb proteins: making bacterial colonisation more difficult |
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What is fluorides action?
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multifactorial and most importantly posteruptive
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