Questions and Answers
What is the primary benefit of fluoride after teeth have erupted?
Which concentration of fluoride is equivalent to 1ppm?
Which of the following compounds is formed when fluorine reacts with calcium?
What element is fluorine most similar to in terms of reactivity?
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How has fluoride been administered to provide dental benefits?
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Fluoride is classified as which type of element?
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What happens to hydrogen fluoride (HF) in the neutral pH environment of the cytoplasm?
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What is the effect of fluoride on mineralized tooth tissues during development?
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How does the acidity of gastric content affect fluoride absorption?
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What is the ionic compound formed from calcium and fluoride?
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In which area does the fluoride concentration in dentine decrease progressively?
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What percentage of fluoride is typically absorbed when food rich in calcium is consumed?
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What primarily influences the percentage of fluoride reabsorbed from the renal tubules?
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How does the fluoride concentration in bulk enamel relate to fluoride exposure?
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Where is most of the fluoride that escapes absorption from the stomach absorbed?
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What role does plasma play in fluoride distribution in the body?
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What happens to surface enamel fluoride concentrations as a person ages?
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Which fluoride compound is less completely absorbed due to lower solubility?
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Which body fluid primarily excretes fluoride?
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What is the significance of the ionic form of fluoride in human plasma?
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How long does it typically take for peak plasma concentration of fluoride to occur after absorption?
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Which factor is NOT mentioned as influencing urinary fluoride clearance?
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Which statement accurately describes the relationship between plasma fluoride levels and age?
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What factor significantly affects the clearance of fluoride from the body?
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What characteristic of fluoride in bone distinguishes it from that in enamel?
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What is generally true about fluoride clearance in adults compared to other halogens?
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What form of fluoride is thought to migrate across cell membranes and establish diffusion equilibrium?
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What is the approximate percentage of the body burden of fluoride associated with calcified tissues?
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During acute fluoride toxicity, which physiological adjustment may help promote fluoride flux out of cells?
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In which region of the body is fluoride concentration highest in long bones?
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How does the concentration of ionic fluoride in soft and hard tissue relate to intake?
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Which of the following statements is NOT true about plasma fluoride levels?
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What happens to fluoride excretion in individuals with impaired renal function?
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What is the primary source of fluoride found in feces?
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What percentage of fluoride intake is typically excreted in sweat?
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How much of the absorbed fluoride is reported to appear in saliva?
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What role does saliva play concerning fluoride levels in the oral cavity?
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Which statement about fluoride excretion in human metabolism is incorrect?
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Study Notes
Fluorides in Dentistry
- Fluoride helps control dental caries by enhancing tooth resistance to plaque acids during tooth development.
- Topical fluoride application is most effective post-eruption of teeth, primarily from frequent exposure to low concentrations in water, diet, toothpaste, and mouth rinses.
- Fluoride concentration is measured in parts per million (ppm), equivalent to 1 mg of fluoride per liter of water.
Fluoride in the Environment
- Fluorine, a highly reactive halogen, is never found in its elemental form; it forms salts like calcium fluoride (CaF2).
- Fluoride can be absorbed from multiple sources, including fluoride-polluted air and some fluorinated drugs.
- The absorption of fluoride varies with solubility; highly soluble compounds (e.g., NaF) are better absorbed than less soluble ones (e.g., CaF2).
Distribution of Fluoride in the Body
Fluoride in Plasma
- Peak plasma concentration occurs within 30 to 60 minutes after fluoride intake; no regulated normal physiologic concentration exists.
- Ionic fluoride (inorganic or free fluoride) is significant in dentistry and public health, detected by specific electrodes.
Fluoride in Soft Tissues
- Intracellular fluoride levels are 10-50% lower than plasma concentrations, varying with extracellular pH.
- Hydrogen fluoride (HF) is believed to establish diffusion equilibrium across cell membranes.
Fluoride in Calcified Tissues
- About 99% of body fluoride is found in calcified tissues.
- Fluoride concentration in bones is not uniform; higher levels are found in periosteal regions.
- Dentine fluoride levels are similar to bone, whereas enamel shows lower concentrations, declining over time with wear but increasing in plaque-accrued areas.
Fluoride Excretion
In Urine
- Predominantly excreted through urine, fluoride undergoes variable reabsorption in renal tubules, which fluctuates between 10 to 90%, influenced by urinary pH and flow.
- Normal renal clearance ranges from 30 to 50 ml/min, significantly higher than other halogens.
In Feces
- Most fecal fluoride is unabsorbed fluoride or re-excreted absorbed fluoride, accounting for less than 10% of total fluoride intake.
In Sweat
- Only a small percentage of fluoride is lost through sweat; can rise to 50% during excessive sweating.
In Saliva
- Less than 1% of absorbed fluoride appears in saliva, which is about two-thirds the concentration of plasma fluoride.
- Salivary fluoride is crucial for maintaining levels in the oral cavity, facilitating recycling within the body.
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Description
Test your knowledge on dental caries prevention and the role of fluorides in dentistry. This quiz covers essential concepts related to fluoride use in enhancing tooth resistance against decay. Learn about the mechanisms and benefits of fluoride during tooth development.