ID Blocks

Question 1

What is meant by block anaesthesia?

Answer 1

Solution is deposited at the nerve trunk of the ID nerve before it enters the mandibular foramen.

the whole distribution of the nerve is anesthetised.

Question 2

Numbing time and numbing duration

Answer 2

Takes longer to build up but also lasts longer than LIA

Question 3

Indications of ID block

Answer 3

• PMPR of lower arch
• RSD
• restorations of lower 5-8
• extraction of deciduous molars

Question 4

Treatment Planning

Answer 4

• introduce LA on upper teeth first if possible
• gain pt’s confidence
• blocks can be more uncomfortable to give and have higher failure rate

Question 5

Anatomy for ID block

Answer 5

• ID nerve part of man div of trigeminal nerve V
• lingual nerve
• long buccal nerve

Question 6

Where does lingual nerve innervate?

Answer 6

• lingual gingivae

- anterior 2/3 of tongue

Question 7

Where does the long buccal nerve innervate?

Answer 7

• buccal gingivae of molars

Question 8

From which foramne does the ID block enter and exit the mandible?

Answer 8

• enters from mandibular foramen

- exits from mental foramen

Question 9

How far from target nerve must the solution be deposited?

Answer 9

Within 1mm

Question 10

How far is the needle inserted into the soft tissue for IDB?

Answer 10

Half to 2/3

Question 11

Techniques for IDB

Answer 11

• Direct*
• Indirect
• Cow-gates
• Akinosi closed mouth

Question 12

Why should you never do a bi-lateral IDB?

Answer 12

• extreme discomfort
• difficulty swallowing
• difficulty with speech
• asphyxiation

Question 13

Contraindications for IDB

Answer 13

• infection at site of injection
• pt’s who may bite lip/tongue
• pt’s who can’t sit still/co-operate
• clotting defects/blood thinners

Question 14

For patients on warfarin, when is IDB possible?

Answer 14

If INR is 3.5 or lower, but must be very cautious and have considered all other alternatives

Question 15

Which nerves are anaesthetised with IDB?

Answer 15

• ID nerve
• incisive nerve
• mental nerve
• lingual nerve (as it runs along ID nerve)

Question 16

Which areas are anaesthetised with IDB?

Answer 16

• lower teeth to midline
• body of mandible
• buccal gingivae of molars
• lingual tissues and periosteum
• ant 2/3 of tongue
• FOM

Question 17

Equipment

Answer 17

• aspirating syringe
• 27 gauge needle 35mm long (yellow)
• anaesthetic cartridge

Question 18

What is the target area for IDB?

Answer 18

ID nerve as it passes down towards the mandibular foremen but before it enters the bone of the mandible.

Question 19

Positioning

Answer 19

• 8 o’clock and face pt
• pt semi-supine/supine
• pt mouth wide open throughout admin

Question 20

Landmarks

Answer 20

• coronoid notch
• pterygomandibular raphe
• occlusal plane of lower posterior teeth - aim to inject 1cm above this

Question 21

Parameters for point of injection

Answer 21

• height - coronoid notch
• ant/post placement - 2/3 to 3/4 bet coronoid notch and pterygomandibular raphe
• depth - contact with bone 20-25mm

Question 22

Procedure for IDB and lingual anaesthesia

Answer 22

1) slowly insert needle to contact bone (20-25mm)
2) withdraw 1mm to prevent subperiosteal injection and trapping nerve
3) aspirate
4) deposit 1.5ml over 1min
5) withdraw short distance and re-aspirate
6) deposit 0.1ml then withdraw completely
7) wait 3-5 mins before starting procedure

Question 23

Signs of success

Answer 23

• tingling and numbness of lower lip (mental)

- tingling and numbness of tongue (lingual)

Question 24

Buccal Nerve anaesthesia

Answer 24

• target buccal nerve as it passes over ant border of ramus

Question 25

Buccal Nerve Landmarks

Answer 25

- lower molars - sit at 8 o'clock - needle to periosteum - inject 0.3ml

Question 26

Failure of IDB

Answer 26

- anaesthetic given too low - inject higher - deposited too anteriorly - insufficient solution injected

Question 27

Other IDB Complications

Answer 27

- no contact with bone due to over insertion | - transient facial paralysis - injected facial nerve

Question 28

Transient Facial Paralysis

Answer 28

- facial nerve has been accidently anaesthetised - explain to pt - protect eye as may not be able to blink - should wear off 20-40mins - LA in parotid gland - drooping of eye/corner of mouth - inability to blink/smile

Question 29

Pain on Insertion

Answer 29

- don't contact bone forcefully - withdraw needle slightly before injecting - don't inject into bone - inject slowly

Question 30

Premature bone contact

Answer 30

- 1/2 or less needle depth at contact - needle to far anterior on ramus - withdraw needle slightly to adjust posn

Question 31

Haematoma

Answer 31

- swelling of tissues on medial side of ramus - apply pressure and cold for at least 2 mins - avoided by aspirating, careful technique and checking MH for clotting issues

Question 32

Trismus

Answer 32

- muscle soreness/limited movement of lat pterygoid muscle - treat with mild analgesics/heat therapy - should subside in 24hrs - if severe seek dentist's advice

Question 33

Lip and Cheek biting

Answer 33

- soft tissue anaesthesia lasts longer than pulpal anesthesia - self inflicted trauma can occur - prevent by POI - don't use IDB for uncoop pts - for smokers, advise caution against cig burns, smoke on other side

Question 34

Broken Needle

Answer 34

- faulty needle - bending needle - sudden movement from pt - keep mouth open with hand and remove any fragments with tweezers - if needle lost, inform patient, record incident, refer pt

Question 35

Stop before you Block

Answer 35

- never event i.e. giving IDB on wrong side - all blocks must be supervised - review notes and procedure - confirm correct side - confirm before you give IDB on correct side