Anticaries Agents and Fluoride Mechanism

Anticaries Agents

• Fluoride is commonly used to prevent tooth decay
• Diet plays a role in caries formation, with high carbohydrate diets increasing the risk
• Caries is caused by acids, primarily lactic acid, produced by bacteria metabolizing carbohydrates
• Plaque buildup on tooth surfaces can trap food particles, providing a breeding ground for bacteria
• Fluoride is absorbed from the gastrointestinal tract and deposited in bones and teeth
• Fluoride replaces hydroxyl and carbonate anions in hydroxyapatite, forming fluorapatite
• Fluoride concentration is higher in the surface layer of enamel, both erupted and unerupted
• Fluoride uptake from tissue fluids is limited to the external surface of enamel

The Mechanism of Fluoride Action

• Two main hypotheses for fluoride's anticaries mechanism:
  • Decreased acid solubility of enamel: Fluoride converts hydroxyapatite to fluorapatite, which is less soluble in acidic environments.
  • Bacterial inhibition: Fluoride may inhibit bacterial enzymes, reducing acid production in dental plaque.
• While fluorapatite formation is documented, it may not fully explain the observed decrease in acid solubility.
• Other possibilities include fluoride's role in reducing enamel crystal defects or competing with carbonate during apatite formation.

Administration of Fluoride

• Fluoride can be administered orally or topically, both methods are effective
• Oral administration allows fluoride to enter systemic circulation and be deposited in unerupted teeth
• Fluoridation of public water supplies is a common and convenient method of fluoride delivery
• The typical fluoride concentration in fluoridated water is 0.7 to 1 ppm, equivalent to 2.2 mg of sodium fluoride daily

Specific Fluoride Compounds

• Sodium Fluoride (NaF):

  • Used in dental products and drinking water
  • Protects teeth from acid demineralization
  • Strengthens tooth enamel
  • Prepared by neutralizing hydrofluoric acid with sodium carbonate or by double decomposition of calcium fluoride with sodium carbonate
  • Available as solutions, tablets, oral gels, and mouthwash

• Stannous Fluoride (SnF₂):

  • Extensively used for topical fluoride applications
  • Solutions are unstable and require fresh preparation due to oxidation of stannous cation
  • Stannous cation itself is believed to have anticariogenic effects
  • Occurs as a white, crystalline powder, freely soluble in water, and topical use only.

Cleaning Agents / Dentifrices

• Dentifrices are used for cleaning tooth surfaces and polishing
• They contain abrasive agents to remove plaque and debris
• Calcium salts are commonly used as abrasive agents in dentifrices
• Fluoride can react with calcium salts to form insoluble compounds like calcium fluoride, reducing fluoride availability
• Calcium pyrophosphate and sodium polyphosphate are used to overcome this incompatibility and maintain fluoride efficacy

Desensitizing Agents

• Desensitizing agents reduce teeth sensitivity to heat and cold

• They act as local anesthetics

• Examples include strontium chloride and zinc chloride

• Strontium Chloride (SrCl₂):

  • Prepared by adding strontium carbonate to hydrochloric acid
  • Used as a desensitizing agent in dental remedies

• Zinc Chloride (ZnCl₂):

  • Occurs as a white crystalline powder or granules
  • Very deliquescent, acid to litmus
  • Highly soluble in water, alcohol, and glycerin
  • Used as an astringent and dentin desensitizer

Dental Cements and Fillers

• Dental cements are used to temporarily cover and protect areas that have undergone dental surgery.

This quiz explores the role of fluoride in preventing tooth decay and its mechanism of action against caries. Delve into how fluoride interacts with enamel and the factors influencing caries formation, including dietary impacts and bacterial activity.