LA Symposium Flashcards
infiltration vs block
infiltration = terminal branches of nerves. for soft tissues of area and pulpal anaesthesia in maxilla and lower anterior teeth if alveolar bone is thin
block = beside nerve trunk, abolishes sensation distal to site, for soft tissue/pulpal where bone is too thick i.e. mandible and for multiple tissues in 1 injection
what anaesthetises dental pulp and buccal gingivae
buccal infiltration
where and what nerves does palatal infiltration anaesthetise
palatal mucoperiosteum NOT PULLP ETC and nasopalatine nerve (anterior 1/3) and greater anterior palatine nerve (posterior 2/3)
what impacts diffusion of anaesthetic
increased age due to increased maxillary and mandibular bone density
what does IDB anaesthetise
- all teeth in quadrant (inferior alveolar nerve)
- most of tongue and lingual gingivae on respective side (lingual nerve)
- lower lip and chin on one side (mental nerve)
buccal molar mucosa unanaesthetised - need long buccal
how to anaesthetise the lingual nerve
using last 1/3 of cartridge after withdrawing 1-2mm from IDB. this catches lingual surface of teeth and soft tissue
where is lingual nerve located in relation to inferior alveolar nerve
anterior and medial to inferior alveolar nerve
buccal nerve block / long buccal - why and how
why - for lower 6 7 8 that is not numbed in IDB
how - distal and buccal to last molar near anterior border of ramus at level of occlusal plane
what kind of injection anaesthetises premolars/canines/incisors and skin of lower lip and chin
mental nerve block i.e. everything anterior to mental foramen
calculation for safe dose
max allowed dose mg/kg x weight in kg/10 x 1/concentration of LA
cause and treatment of trismus
cause - hitting medial pterygoid
treatment - diazepam and ibuprofen
iatrogenic damage from LA
facial palsy from depositing LA in parotid gland as CN VII runs through here
intra oral topical anaesthesia
benzocaine 20% flavoured gel
lidocaine 2% gel / 10% spray / 5% ointment
extra oral topical anaesthesia
EMLA cream - 5% prilocaine and lidocaine. needs to be applied for 1hr
Ametop gel - tetracaine 4% gel. faster onset than EMLA
quicker half life - lidocaine or articaine
articaine - 20 mins
lidocaine 1.5-2hrs
if contraindications are sickle cell anaemia and other haemoglobinopathies what is the drug
articaine
contraindications of lidocaine
heart block w no pacemaker, impaired liver function, hypotension
max dose lidocaine 2% plain / w epinephrine
4.4mg/kg
max dose prilocaine 4% / 3% w felypressin
6mg/kg
max dose mepivicaine 3% plain / 2% w epinephrine
4.4mg/kg
max dose articaine 4% w epinephrine
7mg/kg
what axons are more susceptible to LA and why
smaller diameter axons as they have fewer layers of sodium channels
reducing agent in LA preparations
sodium metabisulfide - no longer used
what preparations are esters
benzocaine
what preparations are amides
lignocaine (aka lidocaine)
prilocaine
articaine
bupivicaine
what are vasoconstrictive agents
adrenaline / octa- or felypressin
action and effects of adrenaline
- binds to alpha receptors in peripheral vasculature for vasoconstriction
- tachycardia due to impact on beta 1 adrenergic receptors in heart wall
- increase in HR + BP
what should you never give for IDB
articaine
landmarks for IDB
coronoid notch
pterygomandibular raphe
posterior border of ramus
symptoms of adrenaline overdose
sweating / pallor / anxiety / weakness / palpitations / trembling / headache / dizziness
trismus vs facial palsy
t - limited mouth opening, onset within hrs of IDB, lasts weeks - months, damage to medial pterygoid (needle too low / forceful administration
fp - complete unilateral facial palsy, onset within mins of IDB, lasts hrs, LA injected into parotid
how does damage to medial pterygoid happen
needle too low
excessively forceful administration
what reducing agents cause reactions
sodium metabisulfates = corn allergy
methyl parabens = blueberry allergy
to reduce pain in anxious patient
- topical - benzocaine 20% or xylocaine 5%
- slow delivery rate
- reassurance and relaxation
- distraction
why aspirate
injecting adrenaline into blood vessel can cause cardiovascular or CNS toxicity as well as tachycardia and hypertension. potentially lethal
extraction of 14. what LA technique would you use
infiltration (distal to apex of tooth) to catch posterior, middle and anterior branch of alveolar nerve
use a shorter 25mm blue needle
bevel to bone
3 branches of maxillary nerve
zygomatic, pterygopalatine ganglion, infraorbital
3 trunks of mandibular division
main trunk
posterior trunk
anterior trunk
why may your anaesthetic not work
necrosis
infection
handler technique
anatomy of patient
3 divisions of trigeminal arise from
trigeminal ganglion found in middle cranial fossa
CNV1 exits middle cranial fossa via
superior orbital fissure
CNV2 exits middle cranial fossa via
foramen rotundum
CNV3 exits middle cranial fossa via
foramen ovale
after exiting skull where does each branch of CNV go
V1 - orbit
V2 - pterygopalatine fossa
V3 - infratemporal fossa
sensory innervation of CNV3
general sensation of anterior 2/3s of tongue
tempoauricural skin
lower lip and chin
mandibular teeth
motor innervation CNV3
muscles of mastication
relationship between lingual nerve and chorda tympani
fibres from facial nerve (CNVII) via chorda tympani travel in lingual nerve (branch from CNV3) and carry:
taste - to anterior 2/3s of tongue
parasympathetic - to submandibular and sublingual glands via synapse at submandibular ganglion
relationship between lingual nerve and chorda tympani
fibres from facial nerve (CNVII) via chorda tympani travel in lingual nerve (branch from CNV3) and carry:
taste - to anterior 2/3s of tongue
parasympathetic - to submandibular and sublingual glands via synapse at submandibular ganglion
function of CNV2 (maxillary)
sensory - lower eyelid, cheek, side of nose, part of nasal cavity, upper lip, hard and soft palate, maxillary teeth and gingivae
5 branches of maxillary nerve that exit pterygopalatine fossa
- greater & lesser palatine nerves exit via palatine canal
- posterior superior alveolar nerve exits via pterygomaxillary fissure
- infraorbital nerve exits via inferior orbital fissure
- nasopalatine nerve exits via sphenopalatine fossa
- pharyngeal nerve exits via palatovaginal canal
anterior trunk CNV3
motor = deep temporal nerves, nerve to lateral pterygoid, masseteric nerve sensory = buccal nerve (not to be confused with buccal branch of facial cranial nerve)
posterior trunk CNV3
sensory = lingual nerve, auriculotemporal nerve mixed = inferior alveolar nerve - once it enters mandible via mandibular foramen it is only sensory, the motor parts come off the mylohyoid muscle
main trunk CNV3
motor = branch to tensor tympani, branch to tensor veli palatini, nerve to medial pterygoid sensory = meningeal nerve (sensory to dura mater)
inferior alveolar nerve branches in relation to oral cavity
branches include: incisive nerve to lower anterior teeth and mental nerve to skin of chin and lower lip
lower teeth and gingivae general sensory supply
premolars + molars = inferior alveolar nerve
incisors + canines = incisive branch of IAN
palatal gingivae = lingual nerve
buccal gingivae = buccal nerve
anterior gingivae = mental nerve from IAN
anterior 2/3s tongue
general sensation supplied by lingual nerve from CNV3
taste supplied by CNVII (facial nerve) via chorda tympani which travels with lingual nerve
posterior 1/3 tongue
both touch and taste supplied by glossopharyngeal CNIX
