Local Anaesthetic

Question 1

what is in a LA

Answer 1

type - ester or amide
vasoconstrictor - felypressin or adrenaline
preservative - propylparaben, bisulphite

Question 2

what is mainly used in the maxilla to achieve anaesthetic

Answer 2

pulp and buccal mucosa - buccal infiltration

palatal mucosa - palatal injection

Question 3

what is used in the mandible to achieve anaesthetic

Answer 3

pulp - posterior - IADB, middle - mental block, anterior - buccal infiltration
buccal mucosa - long buccal infiltration
lingual mucosa - lingual infiltration when administering IADB

Question 4

what types of injections are commonly used and what is the difference

Answer 4

infiltration - anaesthetising terminal nerve ends

block - anaesthetising nerve trunk, any branches distal to this are blocked

Question 5

what are the steps required prior to injecting

Answer 5

check patients medical history - no contraindications
check batch number and expiry date of LA
record these
set up equipment, with safety plus system
dry mucosa
apply topical for 1-2 minutes
calm the patient and reassure, distraction and breathing

Question 6

what is the technique for administering LA

Answer 6

stretch mucosa, have needle orientated with bevel away from bone, quickly pierce mucosa, once in correct place, aspirate, then slowly drip the LA in

Question 7

why must aspirate be carried out

Answer 7

checks for blood in the cartridge, if so, in a blood vessel, must come out, change cartridge, and re-orientate

Question 8

what size of needles are used

Answer 8

25mm - infiltration

35mm - block

Question 9

where should a buccal infiltration be administered

Answer 9

reflect the mucosa, into the mucosa below apex of tooth - if lower - slightly distal

Question 10

what are the positives and limitations of buccal infiltration

Answer 10

positives - easy technique, atraumatic, can get good topical anaesthetic
limitations - dense bone, periapical abscess

Question 11

what are the landmarks in an IADB

Answer 11

coronoid notch, posterior border of ramus of mandible, pterygomandibular raphe, premolars on the opposite side

Question 12

where are you aiming to deposit the LA in an IADB

Answer 12

mandibular foramen

Question 13

how should the LA needle be orientated in IADB

Answer 13

handle along the premolars on the opposite side, needle 1cm above the occlusal surface of molars

Question 14

how can the lingual nerve be anaesthetised during IADNB

Answer 14

after 3/4 of cartridge is deposited, take the needle out 3-4mm, then deposit the remainder of cartridge, this should target the lingual nerve

Question 15

how can you confirm anaesthesia

Answer 15

numb, tingly, shouldnt extend past the midline, if doing extraction, could probe the PDL, but if restoration, could do damage

Question 16

what is the % of lidocaine used and what is its safe dosage

Answer 16

2% lidocaine with 1 in 80,000 adrenaline

5mg/kg safe

Question 17

what is the % of prilocaine used and what is its safe dosage

Answer 17

3% prilocaine with felypressin/octapressin

8mg/kg safe

Question 18

what is the % of articaine used and what is its safe dosage

Answer 18

4% articaine with 1 in 100,000 adrenaline

7mg/kg

Question 19

what are the dangers of articaine

Answer 19

high percentage, unsure of the damage to nerves, shouldnt be used as a block until confirmed

Question 20

give some examples of systemic complications with LA

Answer 20

psychogenic stress - increase HR, blood away from brain, may cause unconsciousness
allergy, toxicity, drug interactions - beta blockers, cocaine, antidepressants

Question 21

what are some examples of local complications with LA

Answer 21

trismus - damage to medial pterygoid muscle
nerve damage - injecting into nerve, prolonged anaesthesia
facial palsy - into soft tissue, diffuse through to parotid and through facial nerve
intravenous - worsened systemic complications, anxiety, increased HR, pale