Local anaesthetic 2 Flashcards
What is Felypressin and why do we use it?
Brand name octapressin. A vasoconstrictor. It is an alternative to adrenaline (chosen for hypertensive patients)
Compare infiltrations to Blocks
Blocks inject the trunk of the nerve.
Infiltrations inject at the terminal branches of the nerves.
Blocks use a 35mm needle(yellow cap).
Infiltrations use a 25mm needle(blue cap).
How does Bone density affect infiltrations?
Dense bone prevents infiltration from working. The bone is too thick for the LA to penetrate (e.g posterior mandible)
4% articaine can be used to provide an infiltration on the mandible.
When would you choose a nerve block over an infiltration?
When you are working on many teeth (infiltrations can only numb 1 or 2 teeth)
Or on dense bone
What LA technique would you use to anaesthetise the Dental pulp of the maxilla?
Buccal infiltration
What LA technique would you use to anaesthetise the Buccal gingivae of the maxilla?
Buccal infiltration
What LA technique would you use to anaesthetise the palatal gingivae of the maxilla?
Palatal infiltration
How would you anaesthetise a lower molar or second premolar
Pulp- inferior alveolar nerve block
Gingivae- Buccal infiltration
Lingual- Lingual infiltration
How would you anaesthetise a lower premolar or canine
Pulp- Mental nerve block
Gingivae- mental nerve block
Lingual- lingual infiltration
How would you anaesthetise the lower canines and incisors.
Pulp - buccal/ labial infiltration
Gingivae- buccal/ labial infiltration
Lingual- lingual infiltration
You are restoring a tooth, what tissue(s) should be anaesthetised
dental pulp
You are extracting a tooth, What tissue(s) should be anaesthetised?
Pulp and gingivae
You are scaling a tooth, What tissue(s) should be anaesthetised?
gingivae or Pulp and gingivae (if doing root surface debridement)
Compare clicking the barrel closed once and clicking the barrel closed twice.
1 click- closed for safety- can still be re-opened
2 click- closed permanently- cannot be re-opened and goes to sharps.
Why do we record the batch number of the LA cartridge ?
For tracking purposes.
Why do we dry the patient’s mucosa before administering topical A?
As a wet mucosa would dilute the Topical anaesthetic
Blood is present in the cartridge after aspiration. How do you respond?
Do not inject the LA. Change cartridge and reposition the needle.
Why do we inject the LA slowly?
As injecting it quickly would force the LA in and upregulate the pain response.
Why is the needle beveled?
To provide a cutting surface that offers little resistance when penetrating and withdrawing the needle.
Where is the needle positioned for a buccal infiltration?
At the apex of the tooth on the distal side.
Where is the needle positioned for a mental block?
Between the apices of the lower premolars (but not in the mental foramen)
Where is the needle positioned for a posterior superior alveolar nerve block?
Mesial buccal fold of the 2nd maxillary molar
Where is the needle positioned for the middle superior alveolar nerve block?
Mesial buccal fold of the 2nd maxillary premolar
Where is the needle positioned for the anterior superior alveolar nerve block?
Mesial buccal fold of the maxillary first premolar (Infra orbital foramen).
What needle is used in an inferior alveolar nerve block?
35mm
Why is the tissue tightened before adminstering LA?
To make the tissue easier to penetrate
What are the landmarks for an Inferior alveolar nerve block?
thumb- coronoid notch
Finger- posterior border of the mandible shown by the pterygomandibular raphe.
Discuss the vertical and horizontal positioning of an IAN?
vertical 6-10mm above the teeth
Horizontal- 3/4 of the way between the thumb and the pterygomandibular raphe
How do you know that the needle is in the correct position?
You contact the bone when 3/4 of the needle has disappeared
1/4 of the needle has disappeared before bone contact how do we fix this?
needle is too anterior (reposition mesially)
All of the needle has disappeared and there is no bone contact. How do we fix this?
needle is too posterior (re-position distally)
Compare the main types of LA used?
Mepivicaine -3 % - works for a shorter period of time. (no vasoconstrictor)
Lignocaine- 2%
Articaine- 4% (proccessed in the plasma)
Prilcaine=-3%
What anaesthetic would be selected as the ‘Go to’ drug.
Lignocaine- gives good level of LA without the risks of 4% articaine.
What are the systemic complications of LA?
Psychogenic/stress
- drug interactions
- allergy
- induced pregnancy (due to felypressin)
Collapsing
Toxicity
What are the clinical features of anxiety?
- pallour
- beads of sweat
- shaking
How do we manage a patient who is anxious?
lay patient flat and lift their legs
Loosen neck clothing
Improve ventillation
Give them sugar (may be due to lack of food)
What drugs interact with LA adrenaline?
- antidepressants M.A.I.Os and tricyclates
- Beta blockers
- Non pottasium sparing diuretics
- Coccaine
Give the max safe dosage, Mgs in a cartridge and max cartridges for Mepivicaine
max safe dosage- 3mg/kg cartridge- 66 max cartridges- 6
Give the max safe dosage, Mgs in a cartridge and max cartridges for Lignocaine
max safe dosage- 5mg/kg cartridge- 44 max cartridges- 7
Give the max safe dosage, Mgs in a cartridge and max cartridges for Articaine
max safe dosage- 7mg/kg cartridge- 88 max cartridges- 5
Give the max safe dosage, Mgs in a cartridge and max cartridges for Prilocaine
max safe dosage- 8mg/kg cartridge- 66 max cartridges- 8
How does adrenaline affect the heart?
Increases heart rate
increases heart force
increases heart output
Increases heart excitability
Discuss the dangerous of adrenaline
- Worries of increasing blood pressure in patients with cardiac disease
- Hyperthyroidism
- Phaeochromocytoma (extra adrenaline causes hypotension.
- Patients on diuretics (increased adrenaline decreases K+ conc in plasma. This is already low in patients on thiazide diuretics.
What causes prolonged anaesthesia?
Direct trauma from the needle
Multiple passes with the same needle
Injecting the LA into the nerve
What is trismus? Give its presentation cause and management
Muscle spasm
Presentation: Patient unable to open mouth
Cause: Injection to medial pterygoid
Management: Reassurance Muscle relaxants e.g. Diazepam
Give the presentation/ cause diagnosis and management of facial palsy?
Presentation: Full paralysis
Cause: injection into parotid gland
Diagonsis: test the facial nerve
Management : Reassurance Cover with eye patch until blinking reflex returns
What is an alternative technique for palatal anaesthesia?
The chasing technique. (You numb an area which then blanches. You then inject that area) Eventually this numbs the palate.
When would you use intra-osseus anaesthesia?
When the LA is not working for the dental pulp but works for everything else. So you drill a hole in the already numb alveolar bone and inject the LA directly.
How does the akinosi technique help treating patients with trismus?
The trismus may be caused by the excessive pain. So by killing the pain- it enables the patient to open their mouth allowing the usual LA technique.
compare the wand to a hand syringe?
A wand administers the local anaesthetic at a lower constant pressure.
When do you use a nasopalatine block?
When anaesthetising upper maxillary anterior teeth.
Compare Articaine to lignocaine?
Articaine is processed in the plasma and has a lower risk of systemic toxicity (The drug is hydrolysed quicker in blood)
Lignocaine- This is the drug of choice. It is also anti-arrhythmic so should not be used if the patient has heart block or a pacemaker.
Compare the two options for surface anaesthesia?
Physical e.g. ethyl chloride (which reduces the temperature of the skin to give local anaesthetic)
Pharmacological e.g. benzocaine (topical anaesthetic )
Compare EMLA cream to Ametop gel?
EMLA cream is an euteric mixture of prilocaine and lidocaine that is placed for 45 minutes.
Ametop gel is a tetracaine 4% gel and this has a faster onset
Compare the depth of tissue of an intra-oral topical agent to that of the wand?
An intra-oral topical agent can anaesthetise tissue 2-3mm deep.
A wand can anaesthetise tissue 1cm deep. (much deepr)
What is transcutaneous electrical nerve stimulation?
Where probes on either side of the area needing numbed block large myelinated nerve fibres. This also closes the gate to the central transmission of unmyelinated nerve fibres.
Compare the mental foramen of an adult to a child.
A child’s foramen faces anteriorly (to the front)
An adults foramen faces posteriorly (to the back)
How do we treat toxicity.
- Stop dental treatment.
- Provide basic life support.
- Call for medical assistance
- Protect patient from injury.
- monitor vital signs.
What is the most common complication of LA for children?
Self inflicted trauma and ulceration.
Where is the needle positioned for a lingual infiltration?
In the reflected mucosa below the tooth in question.
What is a hyperaemic pulp and how do we deal with it?
This is a tooth that won’t go numb after our LA injections.
To treat this we use:
Intrapulpal or intraligamentary injections
Compare intra-pulpal and intra-ligamentary injections
Intrapulpal- you inject LA directly into the root and you need access to the canals for this- useful if you are struggling with anaesthesia pre-root canal.
Intra-ligamentary - The needle is inserted into the PDL space and injected so it goes into the alveolar bone.
What are the difficulties with giving a patient intraligamentary LA?
- It is painful
- It is difficult to ensure you are in the PDL space
- Small risk of injecting the IDN
- LA only lasts a short period of time.
