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Anesthesia: INBDE study notes and practice questions

Local anesthesia questions mix pharmacology (how the drugs work and are cleared) with applied technique (which nerve you block and what you will feel). Expect patient scenarios about toxicity, medical conditions that change your choice of drug, and what to do when anesthesia fails.

167 practice questions · 3 patient cases

Practice Anesthesia

Where it fits in the official INBDE blueprint

Oral Health Management (pain and anxiety control). Nearest foundation knowledge area: FK 8. See the content outline for the official weights. This mapping is approximate: real items combine a clinical area with a foundation area.

What this area tests

High-yield checklist

Common traps

These notes are original study aids, not official exam content. Confirm clinical details against current guidelines.

Sample questions

1. A patient is unable to lift the right upper lip. What could be the reason?

  1. 1 carpule of 2% Lidocaine infiltration into the maxillary labial vestibule
  2. Right infraorbital nerve block
  3. Right inferior alveolar block
  4. Posterior superior alveolar block
Show answer and explanation

Correct answer: B. Right infraorbital nerve block

The INFRAORBITAL NERVE (V2 branch) exits through the infraorbital foramen and innervates the skin/tissues between the lower eyelid and upper lip (upper lip, lateral nose, lower eyelid). An INFRAORBITAL BLOCK anesthetizes this region, causing inability to lift/feel the upper lip and surrounding area. A labial vestibule infiltration would numb only the local gingival/mucosal area — not the lip levator muscles' sensory area. The infraorbital block is the answer. B is correct.

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2. What is the maximum recommended dose of articaine for dental procedures?

  1. 4 mg/kg (same as lidocaine)
  2. 5 mg/kg
  3. 7 mg/kg
  4. 3.5 mg/kg
Show answer and explanation

Correct answer: C. 7 mg/kg

The maximum recommended dose of articaine is 7 mg/kg (not to exceed 500 mg per appointment). Articaine (4% solution with 1:100,000 epinephrine) is widely used in dentistry. For comparison: lidocaine maximum is 4.4 mg/kg (with epi) or 2.2 mg/kg (plain). Articaine's higher dose allowance is related to its rapid plasma ester hydrolysis by plasma esterases, giving it faster metabolism. It is the only amide anesthetic that also has an ester linkage on its thiophene ring.

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3. A study comparing the efficacy of articaine and lidocaine reports a relative risk (RR) of 3.1 with a 95% confidence interval (CI) of 2.1–4.7 and a p-value <0.001. Based on this data, what can be concluded about the efficacy of these anesthetics?

  1. Articaine is safer to use than lidocaine
  2. Lidocaine is more effective than articaine
  3. Articaine is more effective than lidocaine
  4. Articaine and lidocaine have the same efficacy
Show answer and explanation

Correct answer: C. Articaine is more effective than lidocaine

The study shows a relative risk (RR) of 3.1, meaning patients receiving articaine were approximately 3 times more likely to achieve successful anesthesia compared to lidocaine. The 95% confidence interval (CI) of 2.1–4.7 contains the point estimate of 3.1 and does not cross 1.0, confirming the result is statistically significant. The p-value <0.001 further supports this finding, indicating a very low probability that the observed effect is due to chance. Therefore, the study strongly suggests that articaine is more effective than lidocaine.

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4. What is the buffering agent commonly added to local anesthetic to speed onset and reduce injection discomfort?

  1. Sodium bicarbonate
  2. Sodium bisulfate
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Correct answer: A. Sodium bicarbonate

Sodium bicarbonate is used to buffer (alkalinize) local anesthetic solutions, which increases the proportion of anesthetic in its uncharged (base) form — speeding the onset of anesthesia and reducing the burning/stinging sensation typically caused by the acidic pH of standard LA formulations (especially those with vasoconstrictor, which are manufactured at a lower pH for stability).

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5. What is the best method to confirm complete pulpal anesthesia before initiating endodontic treatment on a mandibular molar?

  1. Ask the patient if their lip and tongue feel numb
  2. Perform a cold test (cold stimulus) on the tooth
  3. Perform an electric pulp test
  4. Ask the patient if they feel no pain when tapping on the tooth
Show answer and explanation

Correct answer: B. Perform a cold test (cold stimulus) on the tooth

Confirming soft tissue anesthesia (numb lip/tongue) confirms nerve block success for the inferior alveolar nerve, but does NOT confirm pulpal anesthesia. The pulp may remain vital and sensitive even when the lip and tongue are numb — a phenomenon common in 'hot teeth' with symptomatic irreversible pulpitis. The gold standard for confirming pulpal anesthesia is a positive pulp vitality test response (cold test) followed by absence of response after anesthesia, or direct testing by probing the pulp chamber without pain. A cold test that elicits no response after anesthesia confirms adequate pulpal anesthesia before initiating access.

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6. Which local anesthetic is associated with methemoglobinemia in infants when used topically?

  1. Mepivacaine
  2. Lidocaine
  3. Benzocaine
  4. Bupivacaine
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Correct answer: C. Benzocaine

BENZOCAINE (ester type) metabolizes to PABA derivatives that oxidize Hgb Fe2+ → Fe3+ (methemoglobin), impairing O2 transport. Especially dangerous in infants (<2 years) with immature methemoglobin reductase. FDA warns against benzocaine teething gels in children <2.

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7. A mother requests medication to reverse the effects of local anesthesia after her child bit his cheek following the last dental appointment. Which of the following is NOT suitable?

  1. Phentolamine (Oraverse)
  2. Naloxone
  3. Massage
  4. Heat
Show answer and explanation

Correct answer: B. Naloxone

Phentolamine (Oraverse) is specifically used to reverse the effects of local anesthesia in soft tissues. Massage and heat can improve blood flow and help reduce anesthesia duration. However, Naloxone is used to reverse opioid overdose and has no effect on local anesthesia.

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8. During administration of local anesthetic, an anxious patient with no pain develops rapid breathing, light-headedness, and tingling of the fingers and around the mouth. The most likely cause is:

  1. Hyperventilation from anxiety
  2. Anaphylaxis
  3. Myocardial infarction
  4. Local anesthetic overdose
Show answer and explanation

Correct answer: A. Hyperventilation from anxiety

Anxiety-driven hyperventilation blows off CO2, causing respiratory alkalosis with light-headedness and paresthesia (perioral and fingertip tingling, carpopedal spasm). Management is reassurance and slowing the breathing so CO2 normalizes; do NOT give supplemental high-flow oxygen.Other options: Anaphylaxis has urticaria/bronchospasm/hypotension; MI has chest pain; LA overdose causes CNS excitation then depression, usually after a high dose.Key exam takeaway: Anxious plus fast breathing plus tingling = hyperventilation; calm the patient and slow the breathing (rebreathe CO2).

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Patient cases

All Anesthesia questions (167)