DDS Dental Pharmacology and Anesthesia 2 — Questions and Answers
Question 1: Nitrous oxide (N₂O) produces analgesia and sedation primarily by:
- GABA receptor potentiation and NMDA receptor antagonism (Correct answer)
- Direct opioid receptor agonism
- Sodium channel blockade in the CNS
- Dopamine reuptake inhibition
Correct answer: GABA receptor potentiation and NMDA receptor antagonism
N₂O exerts its effects via potentiation of GABA-A inhibitory neurotransmission and antagonism of NMDA (glutamate) receptors, reducing pain transmission and producing anxiolysis.
Question 2: A patient taking warfarin requires tooth extraction. Which INR threshold is generally accepted as safe for routine dental extractions without altering anticoagulation therapy?
- INR < 1.5
- INR ≤ 3.5 (Correct answer)
- INR < 2.0
- INR ≥ 4.0
Correct answer: INR ≤ 3.5
Current evidence supports performing routine dental extractions when the INR is ≤ 3.5 without altering warfarin, using local hemostatic measures rather than risking thromboembolic events from stopping anticoagulation.
Question 3: Which antibiotic is the first-line choice for prophylaxis against infective endocarditis before dental procedures in eligible patients?
- Amoxicillin 2 g orally 30–60 minutes before the procedure (Correct answer)
- Clindamycin 600 mg orally 1 hour before the procedure
- Azithromycin 500 mg orally the night before
- Penicillin VK 500 mg orally twice daily for 5 days
Correct answer: Amoxicillin 2 g orally 30–60 minutes before the procedure
Current AHA guidelines recommend amoxicillin 2 g (adults) orally 30–60 minutes before procedures as first-line IE prophylaxis for eligible high-risk patients.
Question 4: NSAIDs reduce dental pain primarily by inhibiting which enzyme?
- Lipoxygenase (LOX)
- Cyclooxygenase (COX), reducing prostaglandin E2 synthesis (Correct answer)
- Phospholipase A2
- Thromboxane synthetase specifically
Correct answer: Cyclooxygenase (COX), reducing prostaglandin E2 synthesis
NSAIDs inhibit cyclooxygenase-1 and -2 (COX-1/COX-2), blocking the conversion of arachidonic acid to prostaglandins, reducing peripheral sensitization and inflammation.
Question 5: Bisphosphonate-related osteonecrosis of the jaw (BRONJ/MRONJ) most commonly occurs after which dental procedure?
- Routine scaling and root planing
- Tooth extraction (dentoalveolar surgery) (Correct answer)
- Composite resin restoration
- Orthodontic bracket placement
Correct answer: Tooth extraction (dentoalveolar surgery)
Tooth extraction and other dentoalveolar surgeries that disrupt the oral mucosa and bone are the most common triggers for MRONJ in patients on bisphosphonate therapy.
Question 6: Which benzodiazepine reversal agent should be available when administering IV conscious sedation in dentistry?
- Naloxone (Narcan)
- Flumazenil (Romazicon) (Correct answer)
- Physostigmine
- Protamine sulfate
Correct answer: Flumazenil (Romazicon)
Flumazenil is a competitive benzodiazepine receptor antagonist that reverses sedation and respiratory depression caused by benzodiazepines used in IV sedation.
DDS Dental Pharmacology and Anesthesia 2
Nitrous oxide (N₂O) produces analgesia and sedation primarily by: