Local Anaesthetics

Question 1

What is the most common use of local anaesthetic?

Answer 1

• Operative pain control
• Minimal caries removal may not require LA (slow speed)
• All other cavity preparations require LA

Question 2

Name 2 uses of LA, other than operative pain control

Answer 2

1. Diagnostic tooth

2. Control of haemorrhage

Question 3

Name 3 forms of surface anaesthetics available

Answer 3

1. Spray
2. Gel
3. Solution

Question 4

Name 2 commonly used surface anaesthetic gels

Answer 4

1. 20% benzocaine

2. 5% lidocaine analgesic

Question 5

What is the most commonly used surface anaesthetic spray?

Answer 5

10% lidocaine

Question 6

Name 2 topical anaesthetics for skin (not recommended intraorally)

Answer 6

1. EMLA (Lidocaine 2.5% and Prilocaine 2.5%)

2. Ametop

Question 7

Name 6 convention LA (amide) solutions used

Answer 7

1. Lidocaine Hydrochloride (2%) with adrenaline (1:80,000)
2. Plain Lidocaine
3. Prilocaine (3%)
4. Mepivicaine Hydrochloride (3%) with no adrenaline
5. Articaine (4%) with adrenaline (1:100,000)
6. Bupivicaine (0.25%) with adrenaline (1:200,000)

Question 8

What is the gold standard UK solution of choice for conventional LA?

Answer 8

Lidocaine Hydrochloride (2%) with adrenaline (1:80,000)

Question 9

Compare articaine to lidocaine

Answer 9

• Fast onset
• Profound anaesthetic so less LA used
• Less preservatives

Question 10

Name 2 commonly used LA techniques in children

Answer 10

1. Infiltration

2. Regional block

Question 11

What is an infiltration anaeshtetic?

Answer 11

Extravascular placement of LA in region to be anaesthetized

Question 12

What is the aim of infiltration?

Answer 12

• Deposit LA near to apex, supra-periosteal
• 0.5-1.0ml sufficient for pulpal anaesthesia
• Buccal approach closer to apex

Question 13

What is the LA technique of choice in the maxilla?

Answer 13

Infiltrations

Question 14

Describe infiltration use in the mandible

Answer 14

• Buccal infiltration adequate for primary molars
• Unreliable for permanent molars
• Block may be better

Question 15

Describe the technique of an inferior alveolar block

Answer 15

• Direct approach from primary molars opposite side
• Syringe parallel to occlusal plane
• Insertion approx 5mm above occlusal plane
• If contact bone immediately, don’t withdraw
• Short needle may be used in yougn child

Question 16

Describe how to carry out a lingual block

Answer 16

Withdraw half way following IDB, aspirate and deposit remaining solution

Question 17

Describe a mental block

Answer 17

• Readily given as mental foramen faces anteriorly
• Needle advanced in buccal sulcus between 1st and 2nd molar apices
• Excellent soft tissue anaesthesia
• Problem for incisors due to cross over supply

Question 18

Describe an intraligamentary anaesthesia

Answer 18

• Intraosseous injection with LA entering via PDL

- Recommended dose is 0.2ml/root

Question 19

Name 2 needle free devices

Answer 19

1. Jet injectors

2. Injex systems

Question 20

Name 3 advantages of needle free devices

Answer 20

1. Mucosa anaesthetised to depth of 1cm without use of needle
2. Deliver jet under high pressure
3. Conventional LA solution used

Question 21

Name 4 advantages of injex systems

Answer 21

1. Expensive
2. Technique not applicable to all areas
3. Soft tissue damage if careless techniques
4. Loud noise and bad taste following delivery

Question 22

Name 3 advantages of intraligamentary anaesthesia

Answer 22

1. Less uncomfortable than IDB or palatal
2. Rapid onset and less effect on soft tissue
3. Use in patients where IDB is containdicated

Question 23

Name a time when IDB is contra indicated

Answer 23

Bleeding disorders

Question 24

Name 2 disadvantages of intraligametary anaesthesia

Answer 24

1. Immature root or short root has risk of avulsion

2. Risk of damage to permanent successor

Question 25

Name 4 contributing factors to the clinical decision on whether to administer LA to a child

Answer 25

1. Age of child and cooperation 2. Urgency and type of treatment 3. Parental input 4. Maxillary infiltration as first experience if possible

Question 26

Describe 4 points of organisation of equipment and materials of administration of LA

Answer 26

1. Sharp fine needle 2. Aspirating syringe 3. Allow LA to reach room temperature 4. Keep out of side

Question 27

Describe a good operator/patient position

Answer 27

- Patient at 30 degrees to vertical - Sit / stand in front at 8 o'clock position - Have assistance present to restrain hands of child if necessary

Question 28

Describe good principles when informing the child about LA

Answer 28

- Explanation is age dependent - Tooth going to sleep, patient awake etc - Explain and show topical gel - Parents on board

Question 29

Describe the technique of infiltration

Answer 29

- Pull cheek so mucosa is taut - Position needle at muco-buccal fold beside tooth - Gently insert needle at same time pulling taut tissue over needle - Reassure and distract child

Question 30

Name 6 components of notes to write up following administration of LA

Answer 30

1. Local analgesic solution and vasoconstrictor, in date 2. Drug concentrations 3. Amount given in cartridges and mL 4. Site of injections 5. Abnormal reactions 6. Post operative instructions given

Question 31

Name 5 general complications of LA

Answer 31

1. Psychogenic 2. Allergy 3. Drug interactions 4. Infection 5. Toxicity

Question 32

What is the maximum dose of lidocaine for a child?

Answer 32

4.4mg / kg

Question 33

How many mg of active ingredients is in one 2.2ml cartridge of 2% lidocaine?

Answer 33

44mg

Question 34

Name 5 early localized complications of LA

Answer 34

1. Pain 2. Intravascular administration 3. Failure of LA 4. Facial nerve paralysis 5. Haematoma formation (trismus)

Question 35

Name 5 late localized complications of LA

Answer 35

1. Self inflicted trauma 2. Oral ulceration 3. Long lasting anaesthesia 4. Trismus 5. Infection (introduction of bacteria at injection site)

Question 36

Name 3 general factors which may contra indicate use of LA

Answer 36

1. Young age 2. Disability prevention cooperation 3. Treatment required (duration, difficult access)

Question 37

Name 3 medical history factors which may contra indicate use of LA

Answer 37

1. Allergy 2. Liver disease (reduce dose) 3. Poor blood supply

Question 38

Name 4 specific techniques which may contra indicate use of LA

Answer 38

1. Bleeding disorders 2. Incomplete root formation 3. Trismus 4. Epilepsy