Overview of Local Anaesthetics Flashcards
what do you consider when choosing your anaesthetic?
type (ester/amide), vasoconstrictor (adrenaline/felypressin), preservative (propylparabens/bisulphites)
who do you never give felypressin to?
pregnant women
where is LA deposited in infiltration techniques?
around terminal branches of nerves
what is infiltration used for?
anaesthetise soft tissues, produce pulpal anaesthesia where alveolar bone is thin, maxilla, lower anteriors
where is LA deposited in a block technique?
beside nerve trunk
what is block used for?
soft tissue anaesthesia, where bone too thick for infiltration, mandible
what tissues do you anaesthetise for tooth restorations?
dental pulp, soft tissues (matrix band/rubber dam placement, haemostatic management in fixed pros)
what tissues do you anaesthetise for extractions and surgical procedures?
pulp, gingiva and surrounding soft tissue
what tissues do you anaesthetise for scaling?
gingivae, pulp
in the maxilla what type of injection do you use to anaesthetise the pulp and buccal gingivae?
buccal infiltration
in the maxilla what type of injection do you use to anaesthetise the palatal gingivae?
palatal injection
for anaesthetising the pulp of lower molars and second premolar what injection is used?
IDB
for anaesthetising the pulp of lower premolars and canines what injection is used
mental (incisive) nerve block
for anaesthetising the pulp of lower canines and incisors what injection is used
buccal/labial infiltration
for anaesthetising buccal gingivae of lower molars and second premolar what injection?
long buccal infiltration
what injection for buccal gingivae of lower first premolar and canine?
infiltration or long buccal or mental nerve block
what injection for buccal gingivae of lower incisors and canines?
buccal/labial infiltration
how do you anaesthetise lingual gingivae?
either second part of IDB by pulling out 1-2mm and injecting again to numb lingual nerve or use a lingual infiltration
what makes up an LA needle?
syringe (and bung), needle (and barrel), cartridge of LA solution)
what is the aspirating technique
pull back on syringe handle to see if needle is sitting in a blood vessel
what is the bevel
the point or tip of needle
what is the gauge?
diameter of lumen of needle, smaller the number the greater the internal diameter
what do greater gauge needles result in?
less deflection so greater accuracy, reduces risk of breakage, easier for aspiration
what is the length of a short needle
20-25mm
what is the length of a long needle and what is it used for?
30-35mm for IDB
what part of the needle should never be inserted and why?
the hub as it is the weakest point and most likely to fracture here
what is the first step of LA preparation
collect syringe handle and needles
what is the second step of LA preparation
collect selected LA cartridges
check batch, expiry date and insert into notes
what is the third step of LA preparation
unpack everything
lay out so you can see everything
what is the fourth step of LA preparation
record details for decontamination, put everything in the notes that you unpackage and pull off
what is the fifth step of LA preparation
make up syringe handle
thumb ring and finger rest, attach silicone ring (bung) place broader end towards handle
what is the sixth step of LA preparation
load cartridge of local anaesthetic solution in needle barrel
place aluminium cap end into needle
what is the seventh step of LA preparation
connect syringe handle and local anaesthetic needle with cartridge
rubber bung goes into cartridge end and clicks into place, check for attachment by tugging
what is the eighth step of LA preparation
prepare needle for use
pull back safety sheath and remove cap then pull sheath down so it clicks once
how do you prepare the patient
medical history, position in chair, dry mucosa, apply topical for 1-2mins, breathing exercise to reduce pain perception
what is the infiltration technique
stretch mucosa, puncture quickly, position needle tip at the target point (apex of tooth), bevel of needle towards bone, aspirate, inject slowly (no less than 30 seconds)
what does infiltration anaesthesia give?
pulpal anaesthesia to one or two teeth, soft tissue anaesthesia, supra-periosteal
what is the limitations to an infiltration
infection can limit effect, dense bone may limit effect
how do you do a buccal infiltration
stretch cheek, puncture mucosa, advance needle until over the apex of the tooth, aspirate, inject, remove syringe, click down once, massage LA into tissue, wait 2 mins
how do you do a palatal infiltration?
use short needle, apply pressure behind injection site with mirror handle, insert needle at 45 degrees angle, inject small amount, blanching occurs
what does a posterior superior alveolar nerve block achieve?
LA in first, second and third molars
how do you perform a posterior superior alveolar nerve block?
insert needle mesio-buccally over maxillary 2nd molar,
how do you perform a middle superior alveolar nerve block?
insert needle mesio-buccally over 2nd premolar
what does a middle superior alveolar nerve block achiever
anaesthetic over 1st molar, premolars and canine
what does an anterior super alveolar nerve block achieve?
anaesthesia of maxillary incisors and canine on side of delivery
how do you perform anterior superior alveolar nerve block
mesio-buccal fold over 1st premolar
what does the greater palatine nerve supply?
posterior portion of hard palate and overlying soft tissue from first premolar to midline
what does the nasopalatine nerve supply?
anterior portion of hard palate bilaterally from 4-4
how do you dispose of sharps
handle off, everything in box with needle double clicked, if cartridge still has LA then it goes into blue lid box
where is the mental nerve?
between apices of lower premolars
how do administer lower buccal infiltration
slightly distal to tooth to be treated
what are the landmarks for IDB?
coronoid notch of mandibular ramus, posterior border of mandible, pterygomandibular raphe, lower premolar teeth of opposite side,
where do you place your hands for an IDB?
finger of non-working hand on posterior border, thumb of non-working hand on coronoid notch
where does the cartridge go when doing IDB?
over premolars on opposite side
what is the limitations of IDB?
increased onset time, increased lingual nerve injury, no change in intravascular injection
where do you inject with an IDB?
6-10mm above occlusal plane, inject halfway between ptergomandibular raphe and coronoid notch
if you have no bone contact with IDB how do you reposition
distally over premolars
if you have bone contact too soon with IDB how do you reposition
mesially over premolars
how do you confirm anaesthesia
ask patient how it feels (rubbery, numb, tingly, swollen, fat)
