Antimicrobial Agents In Periodontal Therapy

Antimicrobial Agents In Periodontal Therapy

Classification of Antibiotics

According to the type of action, antibiotics are classified in the following ways:

• Bacteriostatic: For example, tetracyclines, sulfonamides, erythromycin, etc.
• Bactericidal: For example, penicillins, cephalosporins, etc.
  Bacteriostatic antibiotics inhibit the growth and multiplication of microorganisms, whereas bactericidal antibiotics kill microorganisms.

Following are the antibiotics used commonly in the periodontal therapy:

• The drugs more extensively investigated for systemic use include tetracycline, minocycline and doxycycline, erythromycin, clindamycin, ampicillin, amoxicillin and the nitroimidazole compounds, metronidazole and ornidazole.
• The drugs investigated for local application include tetracycline, minocycline, doxycycline, metronidazole and chlorhexidine.

Penicillins

• Penicillins were the first group of antimicrobials used in periodontal therapy.
• Penicillins are bactericidal but induce allergic reactions.

Tetracyclines

• Tetracycline HCl became a popular choice during 1970s due to its broader spectrum of activity than penicillins, ability to inhibit collagenase activity, which is thought to interfere with the breakdown of periodontal tissues, firm adsorption to tooth surfaces and slow release over time.
• Most of subgingival microorganisms are susceptible to tetracyclines at a minimum inhibitory concentration of 1-2 mg/ mL.

Doxycyclines

• Doxycyclines are the semisynthetic tetracyclines.
• Doxycycline as compared to tetracyclines does not absorbed by calcium, milk and antacids and show better compliance.
• Doxycyclines is recommended in a 100 mg dosage twice daily for first day and then 100 mg four times a day.

Metronidazole

• Metronidazole is a powerful amebicide.
• The drug has selective antimicrobial features against the obligate anaerobes.
• Metronidazole should be given 200 mg for four times a day for one week or 400 mg three times a day for one week.
• Metronidazole is the first choice of drug to treat ANUG and aggressive periodontitis.

Azithromycin

• Azithromycin is taken up by gingival epithelial cells and penetrates fibroblasts and phagocytes. It is transported and released directly into site of inflammation through phagocytosis.
• Azithromycin initial loading dose is 500 mg followed by 250 mg/day for 5 days.