LA4- Maxillary anaesthesia anatomy and techniques Flashcards
what does choice of technique depend on?
- Patient
- Nature ,location and duration of planned procedure
- LA drug
what foramen does the CN Vb exit through?
retundum
what foramen does the CN Vc exit through?
ovale
what nerve innervates the anterior teeth (incisors and canines)?
anterior superior alveolar nerve
what nerve supplies the premolars and the mesio-buccal root of the upper 1st molar?
middle superior alveolar nerve
what nerve supplies the molars?
posterior superior alveolar nerve
what nerves supply the palate?
- incisive branch of nasopalatine nerve
- greater palatine
- lesser palatine nerve
Name 3 local anaesthetic techniques.
- Topical anaesthesia
- Infiltration anaesthesia
- Regional (block) anaesthesia
what are the supplementary techniques to LA?
– Intraosseous anaesthesia – Intraligamentary anaesthesia – Intrapapillary anaesthesia – Intra-pocket anaesthesia – Computer controlled anaesthesia
what are the uses of topical (surface) anaesthesia?
– aid to pain-free injections – very minor surgical procedures – abscess incision – rubber dam clamps -impressions
what are different techniques of topical anaesthesia?
– solutions
– Sprays
– Pastes/gels
– refrigeration – ethyl chloride
what are the 2 main techniques of LA?
- infiltration
- regional (block)
what are the characteristics of the infiltration technique?
- Easy
- Safe
- Low risk of intravascular administration
- Low risk of nerve injury
- Local Haemostasis
- Local diffusion required
- Acts on nerve ‘endings’ rather than trunk
what are the characteristics of the regional (block) technique?
- Can be difficult
- Less safe
- Higher risk of IV admin.
- Higher risk of nerve injury
- Acts on nerve trunk
- Widespread effect from single injection
- Can deposit away from infected areas
what is infiltration?
Deposition / diffusion of LA solution close to, or in the target tissue
what is the efficacy of infiltration governed by?
the ability of the solution to reach the target ( tooth apex)
what needle is used in infiltration?
short needle (25mm-blue cap)
where will infiltrations work?
- thin porous bone
- DIFFICULT - thicker bone due to zygomatic process /divergent roots
where will infiltrations not work?
very dense outer cortical bone
what is infiltrations useful for?
-Pulpal anaesthesia for most upper teeth
– Soft tissue anaesthesia where you put it – buccal. or palatal
when is infiltration difficult?
pulpal anaesthesia upper 1st molars
how does infiltration spread its effect?
ability of solution to diffuse -relatively localised anaesthesia
what is needed before infiltration anaesthesia?
medical history
what equipment is needed for infiltration?
- short needle
- appropriate anaesthetic – normally lidocaine in maxilla
during infiltration, what is the patients position?
– operator preference / patient comfort
– supine (less likely to faint) or upright
Describe the gels technique of topical anaesthesia.
- idenitfy site - site of minor soft tissue procedure
- dry site with 3 in 1
- apply gel - usually on cotton wool roll
- remove cotton wool
how long does it take for topical anaesthesia to work?
between 3 and 5 minutes
-then deliver the injection or perform procedure ( be efficient as topical will not last but don’t rush)
when injection needle, how are soft tissues retracted?
use mirror if possible
Describe the injection of the needle
- hold tissues taught
- bevel facing bone and syringe as 45 degrees to bone
- gently insert needle until bone is contacted
- and withdraw needle by 1mm so its off the surface of the bone
- aspiration
why is aspiration used?
reduce the risk of intravascular injection:
• Failure of LA
• Systemic side effects
what is aspiration?
- Increase pressure inside cartridge (push plunger)
- Then decrease pressure inside cartridge (pull)
- Suction draws what is at needle tip into cartridge
- If blood – likely to be in a vessel
- If no blood – less likely to be in a vessel
what happens if there is clear aspiration?
slowly inject solution
how long does it take to inject 1ml of LA solution?
1 minute
how are pain free injections carried out?
- Topical anaesthetic
-Taught tissue – quick, precise needle
penetration
-Slow injection ~1ml/minute – drizzle! - 2 stage injection for upper anteriors
why are palatal infiltrations uncomfortable?
tightly keratinised mucosa on the palate almost immediately touch bone
what anaesthetic is used for tooth extraction?
- buccal/labial infiltration
- palatal infiltration
what nerves are normally blocked in palatal block anaesthesia?
greater palatine nerve
incisive nerve
why is block anaesthetic in the maxilla used?
– Surgery involving palatal soft tissues in quadrant
– Reduces dose cf. multiple palatal infiltrations
– More comfortable than multiple palatal infiltrations
