LA

Question 0

What are the properties of Lidocaine?

Answer 0

Gold standard is: 2% with 1:80,000 adrenaline

2-5 min onset
Duration: pulpal - 45-60 mins Soft tissue - 2-3 hours

Max dose is 500mg rule is 1 cartridge of lignocaine per 10kg body mass

Question 1

How does LA work?

Answer 1

Reversibly blocks nerve conduction by blocking the sodium channels in a nerve axon.

Prevention of AP when pain stimuli applied

Question 2

What are the properties of Articaine?

Answer 2

4% with 1:100,000/200,000 adrenaline
Shorter half life than lidocaine
1-6 min onset
Duration: pulpal - 75mins Soft tissue - 20-175 mins
Has a higher max dose per kilo than lidocaine 7mg/kg

Question 3

What are the properties of Prilocaine?

Answer 3

3% with felypressin
Not as effective as lidocaine
Duration: pulpal - 60-90 mins Soft tissues - 2-4 hrs
Max dose 8mg/kg

Question 4

Which nerves need to be anaesthetised for a maxillary extraction?

Answer 4

Superior alveolar nerve - buccal infiltration
Greater palatine nerve - palatal aspect of molars and premolars
Nasopalatine nerve - palatal aspect of anterior sextant

Question 5

What nerves need to be anaesthetised for a mandibular extraction?

Answer 5

Inferior alveolar nerve - IDB
Lingual nerve - IDB
Buccal nerve - long buccal

Question 6

What are common failures of LA?

Answer 6

Operator dependent factors: poor technique, insufficient amount, choice of LA

Patient dependent factors: anatomical variation, pathological (inflammation), psychological

Question 7

Immediate Complications of LA?

Answer 7

Facial palsy
Allergic reaction
Pain
Faint
Tachycardia
Needle breaks

Question 8

Delayed complications?

Answer 8

Haematoma
Trismus
Infection
Parathesia
Tissue necrosis

Question 9

How to avoid complications

Answer 9

Take a medical history
Aspirate 
Inject slowly
Don't overdose
Monitor patient 
Avoid regional blocks