Overview of LA Techniques p200 Flashcards
infiltration
local anaesthestic deposited round the termonal branches of nerves
used for soft tissues to the area adminstered (benefits of vasoconstrictor)
produce pulpal anaesthesia if alveolar bone is relatively thin
(maxilla and lower anteriors)
block
anaesthestic deposited beside the nerve trunk
abolishes sensation distal to site
used to produce
- soft tissue anaesthesia
- produce pulpal anaesthesia to teeth where bone is too thick to allow infiltration techniques to work successfully
- mandible
- anaesthesia to multiple tissues using single injection
general injection technique
- stretch mucosa
- puncture mucosa quickly > use distraction (wriggle toes)
- position needle tip at target point
- aspirate
- inject slowly (no less than 30 secs)
- bevel of needle should be towards you so it doesn’t occlude when it hits bone
Maxillary anaesthesia types
buccal infiltration
palatal infitration
intraligamentary injection
infraorbital nerve block
ant, middle and post superior alveolar nerve block
buccal infiltration anaesthetises
dental pulp and buccal gingivae
buccal infiltration technique
Patient sitting up and at 45* angle
Dentist infront and to the side which they are anaesthetising
Draw imaginary line along muco-buccal fold and one up long axis of tooth
Aim to anaesthetise just above the apex (DISTAL TO IT)
1. Stretch Cheek
2. Puncture mucosa with correct bevel of needle
3. Advance needle until over the apex of the tooth
4. If contact bone withdraw slightly
Aspirate -> if negative, inject slowly
-> if positive, reposition and repeat
uses of buccal infiltration
mental block
between apices of lower premolars
buccal injection, lower buccal gingivae
anterior superior alveolar nerve block affects
teeth 1,2, 3
middle superior alveolar nerve block affects
teeth 4, 5, and mesio-buccal of root of 6
posterior superior alveolar nerve block affects
all of 6 (bar MB root), 7 and 8
what nerve may some people not have
middle superior alveolar nerve
so ant 1-4 and post 5-8
palatal infiltration anaesthesises
palatal mucoperiosteum not pulp
2 nerves that can be affected in palatal infiltrations
nasopalatine nerve
greater anterior palatine nerve
nasopalatine nerve innervates
mucoperiosteum of teeth 1, 2, 3 (ant 1/3)
greater anterior palatine nerve innervates
mucoperiosteum of teeth 4, 5, 6, 7 and 8 (post 2/3)
how to do a palatal infiltration
Midway between the gingival margin of the tooth and the median palatine raphe (e.g midline of palate)
Along the long axis of tooth
Hit vault of palatine bone within 2mm of insertion
* injection for the maxillary third molar should be at palatal root of maxillary second molar to avoid anaesthesia of lesser palatine nerves which supply the soft palate = gagging
For Nasopalatine inject at incisive papilla
issue with palatal infiltration
often painful
use CHASING technique
Labial or Buccal first (give time to work) through interdental papilla
- Use mirror to check for blanching of palatal mucosa at the respective area
Anaesthetise the blanched area
Use short needle!!
Can use topical beforehand
LA characteristic
bad taste
no flavour added to reduce allergy risk
intraligamentary injection anaesthetises
PDL
i.e. if pulp and periodontal nerve of tooth being worked on
down long axis of tooth
can use intraosseous anaesthesia with stabident
increased age means
increased maxillary and mandibular bone density
so poorer diffusion of anaesthetic
inferior alveolar nerve block anaesthesis
- all teeth in quadrant
- most of tongue on respective side
- labial/buccal mucosa until 2nd premolar
buccal molar mucosa is unaesthetised
anatomy of IAN
M= Masseter R = ramus AV = inferior alveolar vein IAA = inferior alveolar artery SML = spheno mandibular ligament MP = medial pterygoid muscle LN = lingual nerve B = buccinator PMR = pterygomandibular raphe SCM = superior constrictor muscle P = parotid gland TT = tendon of temporalis L = lingula.
IAN needle passes through
Buccinator muscle and into the pterygomandibular
space where it is directed to an area of bone just superior to the
Lingula
neurovascular bundle for IAN
The Inf Alv N. Inf Alv Vein, and Inf Alv Artery are wrapped together by a fibrous sheath in a neurovascular bundle, which occupies a spooned-out depression on the medial surface of the ramus
lingual nerve location realtive to IAN
superior and medial
amount of LA used for IDB
2/3 cartridge
leave last 1/3 for lingual nerve - deposit on retration (1-2mm)
technique for IDB
- Thumb placed at anterior notch, fingers concavity of ramus outside mouth
- Needle entry junction of buccal pad of fat/Pterygomandibular raphe
- Syringe lies over contra lateral 5-6
- Advanced to bony contact (1cm of needle visible)
- If no bony contact reposition syringe distally
- Roughly 2/3 up nail of thumb horizontally (if thumb in coronoid notch)
buccal nerve block anaestheses
buccal mucosa of lower 6, 7, 8
(not number by IDB)
buccal nerve block technique
- Injection distal and buccal to last molar near anterior border of ramus of mandible
- At level of occlusal plane
- Must be done when operating on any of those teeth
mental nerve block anaesthetises
pulpal anaesthesia for mandibular teeth anterior to the mental foramen
- pre-molars, canine, lateral and central incisor
buccal mucous membrane anterior to the mental foramen
skin of lower lip and chin
mental nerve block technique
Inject at mucobuccal fold at mental foramen located between the apices of the two premolars/canine and deposit into the foramen
Down long axis of teeth
incisive nerve block anaesthetises
- buccal soft tissue
- similar to mental nerve block
use of incisive nerve block
soft tissue biopsy
maxillary nerve
mandibular nerve
complications and contraindications to LA classes
psychogenic causes
drug interactions
allergies
toxicity
pregnancy
pscychogenic complications of LA
- fainting
- bradycardia
- vagal event
pscychogenic complications of LA caused by
lack of oxygenated blood to brain
clincial features of psychogenic complications of LA
- lightheadedness
- pallor
- beads of sweat on face
- bradycardia
- pupil dilation
- nausea
management of psychogic complications from LA
- lie flat and raise legs
- loosen neck clothing (improve room for ventilation)
- sweet drink?
possible drug interactions with LA
- monoamine-oxidase inhibitors (antidepressants)
- tricyclics
- Beta blockers
- non-potassium sparing diuretics
- cocaine
MAOI interaction with LA
most adrenaline metabolised bu catechol-A-Methyl transferase system
if on MAOI it retains adreanline (i.e. not metabolised)
tricyclics interaction with LA
hypertension due to uptake of adrenaline at symptomatic nerve terminals (limit pt to 2 cartridges)
Beta blockers interaction with LA
Beta2 adrengic receptors blocked = increase in vasodilation
non-potassium sparing diuretics interaction with LA
can cause Hyperkalemia due to adrenalines Potassium lowering action = potentioal arrythmia/muscle weakness
cocaine interaction with LA
increased adrenergic activity - Catecholamines (adrenaline) bind to receptors and increase symp activity
allergies to LA
true allergies are v rare (usually due to latex bung)
sometimes methylparaben preservative in LA
clincal signs of LA toxicity
- convulsions
- loss of conciousness
- respiratory depression
- circulatory collapse
pregnancy and LA
felypression (octapressin) has the theoretical potential to induce labour
(acts like oxytocin)
LA effect on cardiovascular system
low level = stimulant
high levels = circulatory collapse
LA effect on CNS
depressant leading to unconciousness and resp arrest
LA and methamoglobin
can cause Methemoglobinemia
- reduced ability of blood cells to release O2 to tissues
cyanosis associated with lethargy and resp distress
prilocaine, articaine and benzocaine
safe dose
maximum allowable dose mg/kg
adrenaline affect on sympathetic nervous system
heart
- increased rate
- increased force
- increased output
- increased excitability
blood vessels
- coronary dilation
- skin contraction
- muscle dilation
blood pressure
- increased systolic pressure
- decreased diastolic pressure
- overall - llittle effect
lungs
- bronchal muscle relaxation
Facial palsy due to LA
hit parotid gland in IDB
affects whole side of face
will wear off with time
stroke
upper spares upper
central lesion so can still use forehead on affected side unlike iatrogenic
what not to use for IDB
articaine
local complication of LA
trismus
facial palsy
prolonged anaesthesia (multiple passes? chemical trauma?
trismus due to LA tx
hit medial pterygoid
treat with diazepam and ibuprofen
systemic diseases to avoid LA
- Cardiovascular disease (use <3 x2.2ml)
- hyperthyroid >thyroid crisis
- phaechromocytoma (hypertension)
- drugs
