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Flashcards in Practical LA Deck (73)
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1

Name the different nerve axons from highest to lowest in susceptibility to LA

A delta
C
A beta
A alpha

2

Describe A alpha nerve axons

Myelinated
Function:
Sensory - proprioception
Motor - mechanoreception

3

Describe A beta nerve axons

Myelinated
Function:
Sensory - mechanoreception

4

Describe A gamma nerve axons

Myelinated
Function:
Motor - muscle spindles

5

Describe A delta nerve axons

Myelinated
Function:
Sensory - mechanoreception, thermoreception, nociception and chemoreception

6

Describe C nerve axons

Unmyelinated
Function:
Sensory - nociception, thermoreception and chemoreception
Autonomic - postganglionic

7

What treatments require the use of LA?

Extractions
Endodontic treatment
Crown prep
Caries removal
Subgingival scaling
Restorations

8

Give examples of ester LAs

Cocaine
Procaine
Benzocaine

9

Give examples of Amide LAs

Lignocaine/lidocaine
Prilocaine
Articaine
Mepivacaine
Bupivacaine
Ropivacaine

10

Which chemicals are often used as vasoconstrictors?

Adrenaline
Felypressin/Octopressin

11

Which preservatives are often used in LA?

Bisulphite
Propylparaben

12

Describe the properties of lignocaine

Lidocaine hydrochloride (2%)
Vasoconstrictor - plain (3%) or 1:80,000 adrenaline (2%)
Metabolised in the liver and plasma
Excreted by the kidneys

13

What is the onset of lignocaine?

Rapid - 2-3 minutes

14

What are common uses of lignocaine and prilocaine?

Infiltrations and blocks

15

Describe the properties of prilocaine (citanest)

Prilocaine hydrochloride (3%)
Vasoconstrictor - plain or felypressin/octapressin (1.2microg)
Metabolised in the liver and plasma
Excreted by the kidneys

16

Describe the properties of articaine (septanest)

4% articaine
Vasoconstrictor - adrenaline, 1:100,000, 1:200,000, 1:400,000
Metabolised mainly in plasma but also liver

17

What is articaine mainly used for?

Infiltrations

18

What are the main differences between articaine and lidocaine?

Articaine is more potent and has a faster onset
Articaine has a shorter fast life and is emiminated quicker

19

What is the most common topical anaesthetic and what flavours does it come in?

Xylonor gel
Comes in mint or bubblegum

20

What are the different types of maxilla LA injections?

Dental pulp - buccal infiltration
Buccal gingivae - buccal infiltration
Palatal gingivae - palatal infiltration

21

What injections are used for the lower molars and second premolar?

Dental pulp - IAN block
Buccal gingivae - buccal infiltration

22

What injections are used for the lower premolars and canines?

Dental pulp - mental nerve block
Buccal gingivae - buccal infiltration or mental nerve block

23

What injections are used for the lower canines and incisors?

Dental pulp - buccal/labial infiltration
Buccal gingivae - buccal/labial infiltration
Lingual gingivae - secondary part of IAN block or lingual infiltration

24

Which nerves supply the upper teeth?

Anterior superior alveolar nerve (V2)
Middle superior alveolar nerve (V2)
Posterior superior alveolar nerve (V2)

25

Which nerves supply the upper gingivae?

Nasopalatine nerve (V2)
Anterior superior alveolar nerve (V2)
Middle superior alveolar nerve (V2)
Posterior superior alveolar nerve (V2)
Greater palatine nerve (V2)

26

Which nerves supply the lower teeth?

Incisive branch of inferior alveolar nerve (V3)
Main trunk of inferior alveolar nerve (V3)

27

Which nerves supply the lower gingivae?

Mental nerve from inferior alveolar nerve (V3)
Buccal nerve (V3)
Lingual nerve (V3)

28

What is the difference between an infiltration and nerve block?

Infiltration blocks the terminal nerve ending
Nerve block blocks the main trunk

29

Describe a good technique for administering LA

Check patients medical history
Position patient in the chair
Dry the mucosa of the selected site of injection
Apply a pea-sized amount of topical anaesthetic to the mucosa for 1-2 minutes
Pull the mucosa tight and puncture the mucosa quickly
Aspirate
Drip LA solution in slowly

30

When is a posterior SAN block used?

For pulpal anaesthesia of the maxillary 6s, 7s and 8s

31

When is a middle SAN block used?

For pulpal anaesthesia of the maxillary 3s, 4s, 5s, and 6s

32

When is an anterior SAN block used?

For pulpal anaesthesia of the maxillary 1s, 2s and 3s

33

Name the important landmarks of an IAN block

Coronoid notch of the ramus
Posterior border of the mandible
Pterygomandibular raphe
Lower premolars on the contralateral side

34

Describe good technique for an IAN block

Advance the needle until you get mandibular contact, withdraw slightly (~1mm)
Aspirate and inject 2/3s of solution then withdraw (~2-4mm)
Inject last 1/3 to anaesthetise the lingual nerve

35

What is the mental nerve and where does it lie

The terminal branch of the inferior alveolar nerve that comes through the mental foramen that sits between the apices of the mandibular 4s and 5s

36

What does a mental nerve block anaesthetise?

The skin in the chin and lip region as well as the buccal mucosa and the teeth from the lower 4 to the midline

37

What is an infraorbital nerve block?

Anaesthesia of the terminal branch of the maxillary division of the trigeminal nerve (CNV2) that passes through the infraorbital foramen

38

What does an infraorbital nerve block anaesthetise?

Sensation to the lateral aspect of the nose, sensation to the skin in this area as well as the maxillary incisors and canines

39

Describe a modified technique for palatal anaesthesia

Give buccal/labial infiltration first
Inject into the interdental papilla next, slowly advancing the needle into the palatal portion of the interdental papilla until the palatal tissues blanch
Inject into the blanched area on the palatal side

40

Why is a modified technique used for palatal anaesthesia?

More time consuming but less painful for the patient

41

What is intraligamentary anaesthesia and when is it used?

Injection of LA into the PDL
Used in oral surgery due to potential damage to the PDL
Often the second option

42

What is the downside to intraligamentary anaesthesia?

Usually only anaesthetises one tooth - may slightly numb the adjacent tooth

43

What is intraosseous injection and when is it used?

Use a stabident perforator and or raise a buccal flap and create a hole through the buccal plate using a small round bur
Last resort but highly effective

44

What are the advantages of topical jet injectors?

Good for patients with bleeding disorders as the mucosa is not being pierced to induce bleeding
Good for those that are scared of needles

45

What are the disadvantages of topical jet injectors?

Expensive
Potential soft tissue damage (operator dependent)
Loud sound
Taste of solution poorly tolerated

46

What are the alternative techniques for an IAN block?

Gow Gates - open mouth technique
Akinosi - closed mouth technique

47

Describe the Gow Gates technique?

Patient lying flat
Aim for the condylar process
Needle inserted into the soft palate past the last standing molar - needle should touch the neck of the condyle

48

What is the advantage of the Gow Gates technique?

With 1 injection, it anaesthetises the IAN, lingual nerve, mylohyoid nerve and long buccal nerve

49

When is the akinosi technique used?

For patients with severe trismus who cant open their mouth - patients should be able to open further after this
Used more often than Gow Gates

50

Describe the akinosi technique

Pull cheek away from teeth and insert needle parallel to the occlusal plane just above the gingival margin of the maxillary molars until the beginning of the needle starts at the level of the 7 or 8
Inject into the area between the maxilla and the ramus of the mandible

51

What is the wand?

A short, fine needle that releases LA solution at a constant pressure when the operator presses on the foot pedal

52

When is the wand used?

Most commonly in paediatrics
Used in intraligamentary anaesthesia - constant pressure reduces chance of the patient experiencing pain
Used for modified PDL injections where the wand tip is inserted into the PDL space, parallel to the long axis of the tooth

53

How should you check for successful anaesthesia?

Ensure patient knows they should still feel pressure, no pain
In anaesthetised area, patient should feel rubbery, numb, tingly and swollen
Consider probing the PDL space to see if the patient can feel it

54

What feelings should patients with IAN block experience?

Tongue and lower lip should be numb to the midline

55

In what diseases should LA dose be altered?

Liver and kidney disease

56

What are the systemic complications of LA?

Psychological
Drug Interactions
Allergy
Toxicity

57

Give examples of psychological LA complications

Fainting, palpitations, pallor, weakness, bradycardia, nausea, pupil dilation, restlessness

58

What causes psychological LA complications?

A lack of oxygenated blood to the brain

59

How should psychological LA complications be managed?

Manage a faint by laying the patient flat, raising their legs, loosen tight clothing around the neck, improve ventilation and give the patient a sweet drink if they have not eaten

60

What drugs commonly interact with LAs?

MAOI’s (antidepressants)
Tricyclics (antidepressants)
Beta blockers
Non-potassium sparing diuretics
Cocaine

61

What should happen if a patient has a suspected LA allergy?

Very rare
Send patient for a patch test - these patients often can’t get treated in a GDP setting

62

Describe toxicity to LA and its effects

Occurs if too much LA is given
Causes circulatory collapse, respiratory depression and loss of consciousness

63

Give examples of local complications of LA

Failure to achieve anaesthesia
Prolonged anaesthesia
Pain during or after injection
Trismus
Blanching
Nerve paralysis
Broken needle infection
Soft tissue damage

64

What is trismus and when does it often occur?

Mouth opening is severely restricted
Can occur following an IAN block
Result of damage to the medial pterygoid

65

What are the different treatments for trismus?

Reassurance
Muscle relaxants ie - diazepam
Therabite or trismus screw to physically open the jaw
Anti-inflammatories ie - ibuprofen

66

Describe facial palsy

Affects the entire facial nerve on one side
Patient cant move any of the muscles on the affected side of the face

67

What causes facial palsy?

LA injection into the parotid gland, which CNVII passes through

68

How is facial palsy managed?

Reassure the patient that it is temporary and cover the eye with a patch until blinking reflex returns to prevent the eye from drying out

69

What are the differences between facial palsy and a stroke?

In a stroke, only the lower portion of the face becomes paralysed
Patient can raise their eyebrows and wrinkle their forehead as the temporal branch of CNVII is spared

70

How are the branches of the facial nerve tested?

Ask the patient to close their eyes tightly, smile, raise their eyebrows, frown and puff their cheeks to determine if the issue is a facial palsy or a stroke

71

What is the maximum safe dose for lidocaine?

2% with 1:80,000 adrenaline - 5mg/kg

72

What is the maximum safe dose for prilocaine?

3% with octapressin - 8mg/kg

73

What is the maximum safe dose for articaine?

4% with 1:100,000 adrenaline - 7mg/kg