DDS Dental Pharmacology and Anesthesia

Question 1

The maximum recommended dose of lidocaine with epinephrine (1:100,000) for a healthy 70 kg adult dental patient is approximately:

Accepted Answer

500 mg (≈13.9 carpules)

Answer

The MRD of lidocaine with vasoconstrictor is 7 mg/kg, giving approximately 500 mg (about 13–14 carpules of 1.8 mL 2% lidocaine) for a 70 kg patient.

Question 2

Which local anesthetic has the longest duration of action for dental pulp anesthesia?

Accepted Answer

Bupivacaine

Answer

Bupivacaine (Marcaine) provides the longest duration of pulpal anesthesia (up to 5–7 hours) due to its high lipid solubility and protein binding.

Question 3

Methemoglobinemia is a specific adverse effect associated with which local anesthetic?

Accepted Answer

Prilocaine

Answer

Prilocaine metabolism produces ortho-toluidine, which oxidizes hemoglobin iron to the ferric state, causing methemoglobinemia at high doses.

Question 4

Epinephrine in local anesthetic cartridges acts by:

Accepted Answer

Causing local vasoconstriction to slow systemic absorption and prolong anesthesia

Answer

Epinephrine binds alpha-1 adrenoceptors causing vasoconstriction, reducing vascular absorption of the local anesthetic and thereby prolonging its duration and reducing toxicity risk.

Question 5

The pKa of lidocaine is approximately 7.9. In an infected (acidic) tissue environment, anesthesia is difficult because:

Accepted Answer

More of the drug is in the ionized (charged) form, which cannot penetrate the nerve membrane

Answer

At lower pH (acidic infection), the equilibrium shifts toward the ionized (protonated, BH+) form of the local anesthetic, which cannot penetrate lipid nerve membranes to reach the sodium channel.

DDS - Doctor of Dental Surgery Practice Test

DDS - Doctor of Dental Surgery Practice Test

DDS Dental Pharmacology and Anesthesia