Local Anaesthetic Overview Part 2

Question 1

What are advantages of safety syringes?

What are disadvantages?

Answer 1

1. Single use
2. Sterile until opened
3. Lightweight

Disadvantages:

1. Requires additional training
2. May feel awkward to first time user

Question 2

What name is given to the first part of the needle that enters the patient?

Answer 2

Bevel

Question 3

What is the most fragile part of the needle?

Answer 3

The hub

Question 4

What is the function of the bevel?

Answer 4

1. Defines the point or tip of the needle, providing cutting surface to penetrate the mucosa with as little resistance as possible

Question 5

How does the angle of the bevel affect the passage of the needle through tissue?

Answer 5

> angle of bevel with long axis of needle > will be the deflection as the needle passes through tissue

Question 6

What does the gauge number represent?

Answer 6

The diameter of the lumen of the needle

Question 7

How does the gauge number relate to the needle diameter?

Answer 7

greater gauge = smaller diameter

Question 8

What are the advantages of a gauge needle?

Answer 8

1. Gauge needles result in less deflection as they pass through tissues which results in greater accuracy
2. Gauge reduces risk of breakage
3. Gauge results in easier aspiration
   - resistance to flow is greater for smaller gauges needles

Question 9

What length do short/long needles measure from hub to tip?

What are the different lengths used for?

Answer 9

Short - 20-25mm
- used for infiltration

Long - 30-35mm
- used for inferior alveolar nerve block

Question 10

List the 5 components of an LA cartridge

Answer 10

1. Cylindrical glass tube
2. Stopper (plunger bung)
3. Aluminium
4. Diaphragm
5. Solution (2.2ml)

Question 11

Describe the equipment you would need to gather for a LA injection

Answer 11

1.syringe handle and bung

2. Syringe barrel
   - short 25mm for infiltration
   - long 35mm for inferior alveolar nerve block
3. Cartridge

Note: check expiry date and batch

Question 12

What are the 3 LA used in clinic and what are the colour codes?

Answer 12

1. Lignocaine
   - blue
2. Articaine
   - gold
3. Citanest

Question 13

What are the components of a syringe handle?

How are these put together?

Answer 13

1. Finger rest
   - slides onto thumb ring
2. Thumb ring
3. Rubber ring
   - attaches to bottom of the thumb ring with the BROADER END FACING TOWARDS THE TOP

Question 14

How do you prepare your safety syringe needle for use

Answer 14

Pull back the safety sheath (no further than 1 click

• remove blue cap from needle
• make the needle safe by re-sheathing

Question 15

How do you prepare a patient for LA injection?

Answer 15

1. Position them in chair
   - this is usually dictated by the type of treatment and technique
2. Dry the mucosa - gauze or cotton wool roll
3. Apply topical for 1-2 minutes
   - pea size on cotton wool

Question 16

What topical gels are normally used ?

Answer 16

1. Benzo gel

2. Xylonor, gingival gel

Question 17

What can you do to help the patient cope with injections?

Answer 17

Show them breathing exercises to help them relax

• reduces tension
• reduces perception of pain

Question 18

Describe the correct injection technique when using LA

Answer 18

1. Stretch mucosa
2. Puncture mucosa quickly
   - use distraction
3. position needle tip at target point
4. Bevel of needle towards bone
5. Aspirate
   - this is to check you are not injecting IV
6. Inject slowly
   - no less than 30 seconds
7. Make needle safe

Question 19

How many teeth does pulpal anaesthesia effect when using infiltration?

Answer 19

1-2 teeth per injection

- also gives soft tissue anaesthesia

Question 20

What are limitations of infiltration anaesthesia?

Answer 20

1. Infection may limit effect

2. Dense bone may limit effect

Question 21

What are advantages of infiltration anaesthesia?

Answer 21

1. High success rate
2. Technically easy
3. atraumatic

Question 22

Describe the correct technique used for buccal infiltration of LA

Answer 22

1. Stretch cheek
2. Puncture mucosa With correct bevel of needle
3. Advance needle until over the apex of the tooth
4. If you contact bone, withdraw slightly
5. Aspirate
   - if negative inject slowly
   - if positive reposition and repeat

Question 23

Describe what should be done after the LA has been delivered (buccal infiltration)

Answer 23

1. Remove syringe from mouth
2. Slide sheath down to first click
3. Can replace cartridge if there is need for further injections
4. Massage local anaesthetic into tissues
5. Wait for 2 minutes for anaesthesia
6. Test

Question 24

Describe how to carry out a palatal infiltration of LA

Answer 24

1. Short needle
2. Area of needle penetration is 5-10mm palatal to the centre of the crown
3. Apply pressure directly behind the injection site with a cotton swab or mirror handle if desired
4. Insert needle at 45 degree angle to the injection site, with the bevel angled toward the soft tissue
5. While maintaining pressure behind the injection site, advance the needle and slowly deposit anaesthetic as soft tissue is penetrated
6. Advance needle until contact is made with bone

Question 25

What causes resistance to deposition of local anaesthetic palatally?

Answer 25

The tissue is very firmly adherent to the underlying periosteum in this region

Question 26

How much LA is required to cause adequate palatal anaesthesia?

Answer 26

0.2-0.4 ml

Question 27

What palatal blocks are available in the maxilla and what areas are affected by them?

Answer 27

1. Greater palatine - posterior portion of hard palate and overlying soft tissues as far as - first premolar and medially to midline 2. Nasopalatine - anterior portion of hard palate (soft and hard tissue) bilaterally from mesial of right first premolar to the mesial of left first premolar

Question 28

Where do you inject to perform a mental nerve block and what must you NOT do?

Answer 28

1. Between apices of lower premolars - massage the LA 2. Do NOT try to put needle in foramen

Question 29

Where should you inject LA for a buccal injection in the lower arch?

Answer 29

Administer to the buccal gingivae slightly distal from the tooth to be treated

Question 30

How do you prepare for an inferior alveolar nerve block?

Answer 30

1. Prepare the equipment and patient as for buccal infiltration - but use 35mm needle 2. Identify site for LA 3. Patient opens mouth - wide stretch - easier land marks - taut tissue

Question 31

What anatomical landmarks are important to look for when performing an inferior alveolar nerve block?

Answer 31

1. Coronoid notch of the mandibular Ramus 2. Posterior border of mandible 3. Pterygomandibular raphe 4. Lower premolar teeth of the opposite side 5. The site of anaesthetic deposition is in the region of the mandibular foramen

Question 32

(for IDB) Where should the needle be placed in relation to the occlusal plane of the teeth below?

Answer 32

6-10 mm above the occlusal plane

Question 33

Describe how to find the correct location for an inferior alveolar nerve block

Answer 33

1. Thumb placed at anterior notch 2. Needle entry at junction of buccal pad of fat/pterygomandibular raphe 3. Syringe lies over contra lateral 5-6 4. Advance to bony contact (1cm of needle visible) 5. If no bony contact, reposition syringe distally 6. If bony contact too soon, reposition mesially 7. When in correct position, withdraw from bony contact 8. Aspirate 9. Inject slowly - for lingual anaesthesia withdraw while injecting last 1/3 of solution

Question 34

How do you confirm anaesthesia with the patient?

Answer 34

1. Ask the patient how it feels - rubbery - numb - swollen/fat - tingly For Inferior alveolar nerve block - tongue and lower lip extending to the mid line on that side should feel different - ability to sense pressure remains