ORS03 - Lecture 1 - LA Overview

Question 1

Define Local Analgesia (1)

Answer 1

Localised loss of pain sensation

Question 2

Define Local Anaesthetic

Answer 2

Drug which reversibly prevents transmission of nerve impulses in the region applied without affecting consciousness

Question 3

What factors affect the speed of LA action? (5)

Answer 3

Tissue pH

pKa of anaesthetic

Nerve morphology

Conc. of anaesthetic

Lipid solubility

Question 4

What factors affect the rate of diffusion away from a nerve? (3)

Answer 4

Protein binding

Conc. of anaesthetic

Lipid solubility

Question 5

How do you increase the duration in which LA works? (1)

Answer 5

Use Vasoconstrictor i.e. Adrenaline

Question 6

Why does the efficacy of LA decrease with inflammation? (3)

Answer 6

LA requires an alkali environment to penetrate the nerves

During inflammation - the environment is acidic

The LA will find it harder to penetrate the nerves

Question 7

What are the 3 divisions of the trigeminal nerve?

Answer 7

Opthalmic (V1)

Maxillary (V2)

Mandibular (V3)

Question 8

What are the indications for Topical Anaesthetic? (3)

Answer 8

Prior to infiltration/Block

Incision/drainage of superficial abscess

Periodontal debridement

Question 9

What are the 3 types of Infilitration?

Answer 9

Supraperiosteal - under mucosa above periosteum

Intraligamentary - along long-axis of tooth into PDL

Submucous - superficially into soft tissue (i.e. lips during biopsy)

Question 10

Describe the bevel position of the syringe when injecting LA

Answer 10