ORE Part 1 Pharmacology in Dentistry

Question 1

What is the mechanism of action of articaine, the most widely used local anaesthetic in UK dental practice?

Accepted Answer

Blocks voltage-gated sodium channels in the neuronal membrane, preventing action potential propagation and nerve conduction

Answer

Articaine (like all local anaesthetics) blocks voltage-gated Na+ channels in the axon membrane, preventing depolarisation and action potential propagation, achieving reversible nerve conduction blockade.

Question 2

What concentration of articaine is most commonly used for dental local anaesthesia?

Accepted Answer

4% articaine with 1:100,000 adrenaline

Answer

4% articaine with 1:100,000 adrenaline (epinephrine) is the most commonly used dental local anaesthetic in the UK for routine procedures. The vasoconstrictor prolongs duration and reduces systemic absorption.

Question 3

Why is adrenaline (epinephrine) added to dental local anaesthetic cartridges?

Accepted Answer

To cause vasoconstriction, reducing systemic absorption, prolonging duration of anaesthesia, and providing a bloodless operative field

Answer

Adrenaline (1:80,000 or 1:100,000) causes local vasoconstriction, reducing blood flow at the injection site. This slows systemic absorption, prolongs anaesthetic effect, and reduces bleeding in the surgical field.

Question 4

What is the maximum safe dose of lidocaine (lignocaine) with adrenaline in a healthy adult?

Accepted Answer

7 mg/kg (up to 500 mg maximum)

Answer

The maximum safe dose of lidocaine with adrenaline (vasoconstrictor) is 7 mg/kg body weight, up to a maximum of 500 mg. Without adrenaline, the limit is 3 mg/kg (up to 200 mg).

Question 5

A patient is taking a non-selective MAOI antidepressant. What dental anaesthetic concern arises?

Accepted Answer

Adrenaline should be used with extreme caution or avoided — MAOIs potentiate catecholamine effects, risking severe hypertension

Answer

Non-selective MAOIs (e.g., phenelzine) prevent breakdown of catecholamines. Adding adrenaline may cause exaggerated and prolonged sympathomimetic effects including severe hypertensive crisis.

ORE Part 1 Practice Test

ORE Part 1 Practice Test

ORE Part 1 Pharmacology in Dentistry