AGD Dental Pharmacology 2 — Questions and Answers
Question 1: What is the first-line antibiotic for treating odontogenic infections in patients without penicillin allergy?
- Metronidazole
- Clindamycin
- Amoxicillin (Correct answer)
- Azithromycin
Correct answer: Amoxicillin
Amoxicillin is the drug of choice for odontogenic infections due to its broad spectrum, excellent oral bioavailability, good bone penetration, and low toxicity.
Question 2: Metronidazole is particularly effective in treating periodontal and odontogenic infections because it is active against:
- Gram-positive aerobic cocci
- Gram-negative aerobic rods
- Strict anaerobic microorganisms (Correct answer)
- Mycobacterial organisms
Correct answer: Strict anaerobic microorganisms
Metronidazole specifically targets strict anaerobes, which are the predominant pathogens in periodontal disease and many odontogenic infections.
Question 3: Which antibiotic causes permanent intrinsic staining of developing teeth when administered to children under age 8?
- Amoxicillin
- Clindamycin
- Metronidazole
- Tetracycline (Correct answer)
Correct answer: Tetracycline
Tetracycline chelates calcium ions in mineralizing tissues, permanently incorporating into dentin and enamel and causing yellow-brown discoloration.
Question 4: Clavulanic acid is added to amoxicillin (Augmentin) primarily because it:
- Enhances amoxicillin penetration into bone
- Extends the plasma half-life of amoxicillin
- Inhibits bacterial beta-lactamase enzymes (Correct answer)
- Reduces gastrointestinal adverse effects
Correct answer: Inhibits bacterial beta-lactamase enzymes
Clavulanic acid is a beta-lactamase inhibitor that protects amoxicillin from enzymatic degradation by resistant bacteria, restoring its antibacterial activity.
Question 5: Clindamycin exerts its antibacterial effect by:
- Inhibiting bacterial cell wall synthesis
- Disrupting the bacterial cell membrane
- Inhibiting DNA gyrase (topoisomerase II)
- Binding to the 50S ribosomal subunit and inhibiting protein synthesis (Correct answer)
Correct answer: Binding to the 50S ribosomal subunit and inhibiting protein synthesis
Clindamycin binds to the 50S ribosomal subunit, blocking translocation and inhibiting bacterial protein synthesis, making it primarily bacteriostatic.
Question 6: The combination of amoxicillin plus metronidazole is used in aggressive periodontal therapy because:
- They are both bacteriostatic and act synergistically
- Together they cover both Aggregatibacter actinomycetemcomitans and strict anaerobes (Correct answer)
- Both drugs are dosed once daily for convenience
- Combined, they reduce the risk of antibiotic resistance
Correct answer: Together they cover both Aggregatibacter actinomycetemcomitans and strict anaerobes
Amoxicillin targets A. actinomycetemcomitans (a key aggressive periodontitis pathogen) while metronidazole covers strict anaerobes, providing complementary coverage.
Question 7: A penicillin-allergic patient requires antibiotic prophylaxis before a dental procedure. According to AHA guidelines, an appropriate alternative is:
- Ampicillin 2 g orally
- Ciprofloxacin 500 mg orally
- Azithromycin 500 mg orally (Correct answer)
- Metronidazole 500 mg orally
Correct answer: Azithromycin 500 mg orally
Azithromycin (or clarithromycin) 500 mg orally 30–60 minutes before the procedure is an AHA-recommended alternative for penicillin-allergic patients.
AGD Dental Pharmacology 2
What is the first-line antibiotic for treating odontogenic infections in patients without penicillin allergy?