Chemical Inhibition of Supragingival Dental Plaque Control

Plaque Control

 

Chemical Plaque Inhibition

Chemical plaque control is used as an adjunct for controlling gingival inflammation and preventing progression of periodontal disease.

Chemical methods are very effective during phase I therapy for patients with recurrent problems.

According to ADA, two agents are accepted for plaque inhibition, i.e. chlorhexidine digluconate and essential oil rinse.

Chemicals Used for Supragingival Plaque Control (Addy’s Classification)

• Antibiotics:
  • Penicillin
  • Vancomycin
  • Kanamycin
  • Erythromycin
  • Spiramycin
  • Metronidazole.
• Enzymes:
  • Mucinase
  • Protease
  • Lipase
  • Amylase
  • Elastase
  • Lactoperoxidase
  • Hypothiocyanate
  • Mutanase.

Read And Learn More: Periodontics Question And Answers

• Quaternary ammonium compounds:
  • Cetylpyridinium chloride
  • Benzethonium chloride
  • Benzalkonium chloride
  • Domiphen bromide.
• Bisbiguanides:
  • Chlorhexidine
  • Alexidine
  • Octenidine/bispyridines.
• Metallic salts:
  • Copper
  • Tin
  • Zinc.
• Herbal extracts:
  • Sanguinarine.
• Fluorides:
  • Strontium fluoride.
• Oxygenating agents:
  • Hydrogen peroxide.
• Phenolic compounds:
  • Thymol
  • Menthol
  • Eucalyptol.
• Other antiseptics:
  • Iodine
  • Povidone-iodine
  • Sodium hypochlorite
  • Hexetidine
  • Triclosan.

Classification of Antimicrobial Agents Used as Chemical Inhibitor of Plaque.

Depending on antimicrobial efficacy and substantivity.

First Generation Agents

• Reduces plaque scores by 20–50%.
• For example, antibiotics, quaternary ammonium compounds, phenols and sanguinarine.
• Efficacy is limited by their poor retention, hence used 4 to 6 times daily.

Second Generation Agents

• These are retained longer in the oral cavity reduce plaque score by 70–90% used 1 to 2 times daily.
• For example, bisbiguanides.

Third Generation Agents

They should be effective against specific periodontopathic organisms. They are yet to be developed clinically.

Description of Chemical Plaque Control Agents

Triclosan

• Triclosan is a phenol derivative, it is synthetic and is nonionic.
• It has a broad-spectrum of activity against gram-positive and gram-negative bacteria.

Mechanism of Action

• It acts over the microbial cytoplasmic membrane and it induces leakage of cellular constituents and leads to bacteriolysis.
• It also delays plaque maturation and inhibit formation of prostaglandin and leukotrienes which are the mediators of inflammation.

Metallic Ions

Salts of zinc and copper are most commonly used metal ions.

Mechanism of Action

They reduce glycolytic activity in microorganisms and inhibit bacterial as well as crystal growth.

Quaternary Ammonium Compounds

• These are the cationic antiseptics as well as surface active agents which are more active against gram-positive as compared to gram-negative organisms.
• Quaternary ammonium compounds are benzethonium chloride, benzalkonium chloride and cetylpyridinium chloride.

Mechanism of Action

Positively charged molecule along with negatively charged cell membrane phosphates disrupts cell wall structure of microorganisms.

Sanguinarine

• It is effective against wide variety of gram-negative microorganisms.
• It undergoes retention with plaque when used as mouthwash.

Antibiotics

• Vanacomycin, erythromycin, nidamycin and kanamycin are used as antibiotics.
• As there are chances of bacterial resistance and hypersensitivity reactions their use is restricted.

Enzymes

• These are mucinase, dehydrated pancreas, dextranase and thiocyanate synthetase.
• Various proteolytic enzymes are bactericidal and are effective when applied in the mouth.
• Enzymes act as active agents and they breakdown already formed matrix of plaque and calculus.

Povidone-Iodine

• It does not show significant plaque inhibition activity when used as 1% mouthwash.
• Various studies shows that it reduces inflammation and progression of periodontal disease.

Bisbiguanides

• Chlorhexidine is a bisbiguanide
• It has most positive antibacterial result
• Two daily rinses with 10 mL of 0.2% aqueous solution of chlorhexidine digluconate almost completely inhibit the development of dental plaque, calculus and gingivitis.

Mechanism of Action

• It has a broad spectrum of antibacterial activity.
• Gram-positive bacteria are more susceptible than gramnegative
• In relatively high concentration, it is bactericidal but in low concentration it may be bacteriostatic
• Cationic molecules of chlorhexidine bind readily to the oppositely charged cell wall and interfere with the membrane transport initiating a leakage of low molecular weight substances
• In high concentration, chlorhexidine penetrates the cell and causes precipitation of cytoplasm (Bactericidal action).

Delmopinol

• It is a low molecular weight amino alcohol.
• Inhibits growth of plaque and reduce the chances of gingivitis.

Mechanism of Action

• It target dextran in extracellular matrix by blocking the synthesis, reducing the viscosity and selectively inhibiting dextran-producing streptococci.
• It also undergoes interference with plaque matrix formation and reduces bacterial adherence. It causes weak binding of plaque to tooth surface and aid in easy removal of plaque.