2. Overview of LA Techniques Flashcards
Function of LA
To prevent pain
Definition of pain
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
Function of vasoconstrictors in LA (2)
Increase length of action of LA
Encourage haemostasis
What is usually the source of LA allergy
Preservatives
Types of LA injections (2)
Infiltration
Nerve block
Process of LA infiltration
LA solution deposited around the terminal branches of nerves
Functions of LA infiltration (2)
Used to anaesthetise soft tissues
Used to produce plural anaesthesia where alveolar bone is thin
Process of LA nerve block
LA deposited beside nerve trunk
Functions of LA nerve block (3)
Abolishes sensation distal (more terminal) to site
Used to produce soft tissue anaesthesia
Used where bone is tooth thick to allow infiltration
Types of anaesthesia in the maxilla (3)
Anaesthesia of pulp - buccal infiltration
Anaesthesia of buccal gingiva - buccal infiltration
Anaesthesia of palatal gingiva - palatal injection
Types of anaesthesia in the mandible (3)
Anaesthesia of pulp - 6-8 (IDB), 3-5 (mental nerve block), 1-3 (buccal/labial infiltration)
Anaesthesia of buccal gingiva - 6-8 (long buccal infiltration), 3-5 (infiltration/long buccal/mental nerve block), 1-3 (buccal/labial infiltration)
Anaesthesia of lingual gingiva - secondary part of IDB if given/infiltration
The tissues to be anaesthetised depends on the procedure (3)
Restoration - dental pulp
Extraction - pulp/gingiva
Scaling - gingiva or pulp/gingiva
Types of syringe barrels and LA uses (2)
Infiltration - short 25mm 30G
IDB - long 30mm 27G
Important cartridge checks (2)
Check expiry date
Check batch number
Preparation of patient (4)
Check MH
Position in chair
Dry mucosa
Apply topical anaesthesia for 3-4mins
Types of topical anaesthetic (2)
2% lignocaine (minty)
20% benzocaine (bubblegum)
Injection technique (5)
Stretch mucosa Puncture mucosa quickly (use distraction) Position needle tip at target point Aspirate Inject slowly (no less than 30s)
Function of the bevel
To provide a cutting surface that offers little resistance to mucosa as the needle penetrates and withdraws from the tissue
Correct bevel orientation
Bevel towards operator during needle placement will leave the lumen unobstructed
Infiltration needle position (3)
Bevel away from bone
If bevel is towards bone, edge of the needle is likely to penetrate the periosteum
Periosteal injections are more likely to evoke a painful response
Definition of aspiration
Blood in cartridge
Importance of aspiration
Allows operator to check if they have perforated a BV (which would cause systemic effects)
Features of infiltration anaesthesia (2)
Pulpal anaesthesia limited to one/two teeth
Soft tissue anaesthesia
Advantages of infiltration anaesthesia (2)
High success rate
Technically easy
Atraumatic
Disadvantages of infiltration anaesthesia (3)
Infection Dense bone (mandible)
Blocks in the maxilla (3)
PSA
MSA
ASA
Sharps disposal (5)
Needle is double clicked to prevent reuse and removed from handle
Needle and sliding sheath are placed in sharps bin (orange bin)
LA cartridge placed in blue bin
Bung is removed from handle and placed in clinical waste (orange stream waste)
Handle and tag are kept to be decontaminated (in dirty room/box)
Important landmarks for IDBs (5)
Coronoid notch of mandibular ramus Posterior border of mandible Pterygomandibular raphe Lower premolar teeth of opposite side Site of anaesthetic deposition is in the region of the mandibular foramen
Limitations of an inferior position of IDB (3)
Increased onset time
Increased lingual nerve injury
No change in intravascular injection
Confirming anaesthesia tips (3)
Ask how it feels (rubbery, numb, swollen/fat)
For IDB - tongue/lip to midline should feel numb
Consider testing with probe
