W12: Local Anaesthesia

Question 1

Define Anaesthesia

Answer 1

Loss of all sensations in a circumscribed area of the body caused by depression of excitation in the nerve endings or inhibition of the conduction process in peripheral nerves.

Question 2

what are the nerves of the maxilla and what do the innervate briefly.

Each take 1

Answer 2

PSA: 2nd 3rd Molars, buccal gingiva, distobucall and palatal roots of mx 1st molar

MSA: MB root of MX first molar and premolars and associated buccal gingiva.

ASA: Canines and incisors and labial gingiva

Greater palatine: Palatal gingiva of post teeth. Post 2/3 of hard palate

Lesser palatine: mucosa of the soft palate and uvula on the given side

Nasopalatine: Palatal gingiva of incisors and canine and the ANT 1/3 of hard palate.

Question 3

What structures are important to consider when giving LA in the maxilla

Answer 3

Greater palatine A
Posterior superior alveolar A
PTerygoid plexus of veins

Question 4

Label this diagram.

Question 5

label

Question 6

label

Question 7

What are properties of the maxilla that is applicable for Local anasthesia administration

Answer 7

• Bone is thicker and denser near the apices of teeth.
• Zygomatic buttress may prevent diffusion of LA to Buccal roots of 1st MX molar

-Pterygoid venous plexus near the MX tuberosity

Thin bone with canals that allows for diffusion of LA

Question 8

what are the 4 main methods for LA administration

Answer 8

Buccal/Labial infiltration
Palatal Infiltration
Nasopalatine Block
Greater palatine Block

Question 9

Describe the steps to performing a LA buccal infiltration

Answer 9

1. Position Patient for optimal Visibility
2. Retract lip and cheek and apply topical Gel at the Height of the mucolabial fold at the level of the tooth.
3. Retract lip using mirror and insert needle with the bevel towards the bone.
4. insert needle 5mm till contact bone
5. Aspirate
6. Inject LA (1ml for Restoration) (2mm for Extraction)

Question 10

What are the advantages and disadvantages of the Buccal infiltration

Answer 10

Advantages:
- Simple technique
- Anaesthetizes all nerve ending irrespective of the nerve

Disadvantages
- Depends of the diffusion of the solution

• Bone thickness
• Localized infection may spread and LA doesn’t work
• Limited zone of anaesthesia

Question 11

Why is a palatal infiltration injection challenging

Answer 11

Its challenging in the ANT 1/3 due to the palate having little submucosal tissue and mucosa is tightly bound to the bone.

Question 12

How deep and how much LA is given for palatal infiltration

Answer 12

insert just enough to get the bevel inside the mucosa. Aprox - 0.5ml a few drops

Question 13

Describe briefly key points for successful administration of the Nasopalatine block infiltration

Answer 13

This will anaesthetize both left and right Nasoplatine nerves. SO all 1/3 of hard palate will be numb.

Apply topical as this is a very painful injection

Insert needle horizontally just lateral to the incisive papilla until the whole bevel is in and deposit 0.3-0.5ml (few drops)

REMEMBER TO ASPIRATE

DO NOT ENTER THE NASOPALTINE FORAMEN

Question 14

Describe the process and key tips for the greater palatine block injection

Answer 14

Locate the greater palatine foramen
- At the junction of the alveolar bone and horizontal process of palatine bone. @ last Molar. (7)

1. apply topical and insert bevel just anterior to the location of the foramen.
2. aspirate
3. administer 0.3-0.5 ml

Do not attempt to enter the Greater Palatine Foramen

Question 16

What are the nerves we anesthetize in the mandible and what do they innervate

Answer 16

IAN: all the teeth and supporting structures on the given side (Buccal)

Incisive: Anterior teeth and supporting structures, and buccal gingiva of the teeth anterior to mental Foramen

Mental: mucosa of the vestibulum and lower lip ant to mental foramen

Buccal : buccal gingiva of the molars and premolars

Lingual: mucosa of the floor of the mouth, Ant 2/3 of tongue. and lingual gingiva of all teeth.

Question 17

what are important structures to consider in the pterygomandibular space

Answer 17

Maxillary artery
- Middle menigeal, pterygoid, IAN, Buccal

Pterygoid venous plexus which help form the maxillary vein

Spenomandibular ligament

Question 18

what can occur if LA is injected into the maxillary vein/ Artery

Answer 18

Intravascular injection and hematoma. which can all lead to the spread of infection.

Question 19

what are key properties of the mandible

Answer 19

Very thick cortical bone (poster especially)

Very few nutrient canals

Large number of muscle attachemnts

close proximity to a number of blood vessels to the nerves we need to numb

foramina and present with location variations

Can have accessory nerve supply to structures

Question 20

what are the techniques of LA administration in the mandible

Answer 20

Ian block (lingual block)
buccal nerve block
mental nerve block
labial and lingual infiltration

Question 21

what are the hard tissue landmarks for Ian blocks

Answer 21

Coronoid Notch
Hamulus
Pterygomandibular rapie
Lingula

Question 22

what are the soft tissue landmarks for an Ian block

Answer 22

Coronoid notch
pterygotemporal depression
pterygomandibular fold

Question 23

describe the Ian block injection technique process

Answer 23

1) position patient sitting @ 45 degrees

2. palpate the coronoid notch/ ext oblique ridge with thumb

3) visualize the pteyrgomandibular fold

4) determine the level of the occlusal plane of MD teeth

5) apply topical

6) position barrel over the opposite side premolars, parallel to the lower occlusal plane

7) Needle enters is 1/2 way between the coronoid notch and pterygomandiular fold @ 1cm able the occlusal plane of teeth.

8) needle is pushed 2/3 of long need until contact with bone is felt (Medial Ramus lateral to the lingula.

9) Aspirate

10) administer 1.4-1.8 ml of LA solution (3/4) of cartridge

11) Withdraw needle towards opposite side premolars

12) after 5mm aspirate again

13) This is the site of the Lingual (administer 0.5 ml)

14) withdraw needle from the pterygomandibular space.

Question 24

why is a buccal infiltration needed along with an Ian block, particularly in extractions

Answer 24

This is because the buccal nerve is not close enough in the pterygomandibular space to be effected by the LA.

Question 25

Describe the process and landmarks for a buccal nerve block

Answer 25

1. Insert needle horizontally and superficially (2-5mm) in to the buccal mucosa. Just lateral and distal to the 2nd molar.
2. aspirate and administer 0.3ml of solution (1/8th of cartiridge)

leave enough in cartridge after Ian block

Question 26

Describe the process of an incisive nerve block

Answer 26

1. insert needle horizontally (2-5mm) into the muccobuccal fold starting just anterior to the foramen. (found between 1st & 2nd premolars)
2. Aspirate and administer 1ml (1/2 cartridge)
3. massage the area will help promote diffusion the solution through the foramen.

Question 27

Describe the process of the labial infiltration technique of the mandible

Answer 27

1. retract lip using hand mirror
2. apply topical at depth of mucosa labial fold at the level of the apex
3. short needle, insert 2-5mm aspirate and administer 1-2ml based on operation

Question 28

describe the process of a lingual infiltration

Answer 28

1. topical applied
2. insert needle superficially just below the attached lingual gingiva of tooth
3. aspirate and administer 0.3ml