ABP ABP Pharmacology and Antimicrobials 1 — Questions and Answers
Question 1: Which systemic antibiotic combination is most commonly used as an adjunct to scaling and root planing for aggressive periodontitis?
- Amoxicillin + metronidazole (Correct answer)
- Doxycycline + azithromycin
- Ciprofloxacin + clindamycin
- Penicillin + tetracycline
Correct answer: Amoxicillin + metronidazole
Amoxicillin combined with metronidazole targets both Aggregatibacter actinomycetemcomitans and anaerobic pathogens associated with aggressive periodontitis.
Question 2: What is the mechanism of action of subantimicrobial-dose doxycycline (SDD) when used as a periodontal adjunct?
- Direct bactericidal activity
- Matrix metalloproteinase inhibition (Correct answer)
- Disruption of bacterial cell membranes
- Inhibition of protein synthesis in pathogens
Correct answer: Matrix metalloproteinase inhibition
SDD at 20 mg twice daily inhibits host-derived matrix metalloproteinases, reducing collagen breakdown without exerting antibiotic effects.
Question 3: Which locally delivered antimicrobial agent releases doxycycline hyclate directly into the periodontal pocket?
- Arestin (minocycline microspheres)
- Atridox (doxycycline hyclate 10%) (Correct answer)
- PerioChip (chlorhexidine gluconate)
- Elyzol (metronidazole gel)
Correct answer: Atridox (doxycycline hyclate 10%)
Atridox is a biodegradable subgingival gel containing 10% doxycycline hyclate that provides sustained release within the periodontal pocket.
Question 4: For a patient allergic to penicillin requiring prophylactic antibiotic coverage before periodontal surgery, which agent is the preferred alternative?
- Metronidazole 500 mg
- Clindamycin 600 mg (Correct answer)
- Azithromycin 500 mg
- Doxycycline 100 mg
Correct answer: Clindamycin 600 mg
Clindamycin 600 mg orally one hour before the procedure is the standard AHA-recommended alternative for penicillin-allergic patients requiring prophylaxis.
Question 5: Chlorhexidine gluconate oral rinse at 0.12% is considered most effective when used in which clinical scenario?
- Long-term plaque control replacement for brushing
- Short-term adjunct during acute pericoronitis management
- Post-surgical infection prevention and plaque suppression (Correct answer)
- Daily rinse for all recall periodontal patients
Correct answer: Post-surgical infection prevention and plaque suppression
Chlorhexidine 0.12% rinse is best used short-term post-surgically to suppress plaque and reduce infection risk when mechanical hygiene is difficult.
Question 6: Which tetracycline has the highest affinity for binding to the root surface and is used in root biomodification protocols?
- Doxycycline
- Minocycline
- Tetracycline HCl (Correct answer)
- Oxytetracycline
Correct answer: Tetracycline HCl
Tetracycline HCl at 50–100 mg/mL has the highest root surface affinity among tetracyclines and has been studied for root biomodification to enhance fibronectin attachment.
ABP ABP Pharmacology and Antimicrobials 1
Which systemic antibiotic combination is most commonly used as an adjunct to scaling and root planing for aggressive periodontitis?