Local Anaesthesia Flashcards
What preservatives are commonly used in LA?
Bisulphite and Propylparaben
What Vasoconstrictors are often used in LA?
Adrenaline and felypresssin
What is the function of adrenaline and felypressin in a LA?
They are vasoconstrictors which provides homeostatic control to the area. This diminishes the blood flow to the area and slows down the absorption therefore prolonging the effect of the anaesthesia.
What is the difference between a nerve infiltration and a block?
Infiltration- anaesthetic deposited around the terminal branches of the nerve
Block- anaesthetic deposited beside nerve trunk
When is it suitable to use an infiltration?
- anaesthetise soft tissues
- pulpal anaesthesia where alveolar bone is thin (Maxilla and lower anterior)
When is it suitable to use a nerve block?
- soft tissue anaesthesia
- anaesthetise teeth where the alveolar bone is too thick to allow infiltration (mandible)
How would you anaesthetise the dental pulp, buccal and palatal gingivae of a maxillary tooth?
Anaesthesia of the dental pulp
-Buccal infiltration
Anaesthesia of the buccal gingivae
-Buccal infiltration
Anaesthesia of palatal gingivae
-Palatal injection
How would you anaesthetise a lower anterior tooth?
Anaesthesia of the dental pulp
-Buccal/ labial infiltration
Anaesthesia of the buccal gingivae
-Buccal/ labial infiltration
Anaesthesia of Lingual gingivae
-Lingual infiltation
How would you anaesthetise Lower Premolars and canines?
Dental pulp - Mental (incisive) nerve block Buccal Gingivae - buccal infiltration or buccal/ mental nerve block Lingual Gingivae - Lingual infiltration
How would you anaesthetise lower molar or second premolar teeth?
Dental Pulp - Inferior alveolar nerve block Buccal gingivae - Buccal infiltration (long) Lingual Gingivae - Lingual nerve block (second part of IAN block if given)
What are the benefits of using a needle with a bigger gauge?
- less deflection through tissues (more accurate)
- easier aspiration
- reduce risk of breakage
What is the bevel of the needle?
Defines the point or tip of the needle, providing cutting surface to penetrate mucosa with as little resistance as possible
> angle of bevel with the long axis of the needle the > will be the deflection as the needles passes through tissue
What length of needle would you use for an infiltration?
25mm (short needle)(blue)
what length of needle would you use for a block?
35mm (long needle)(yellow)
how would you assemble a syringe and anaesthetic ready for use?
- collect syringe handle and needles
- collect LA cartridge (check batch number and expiry date)
- unpack everything and record details for decontamination
- make up syringe handle and attach the rubber bung to end
- Load cartridge of local anaesthetic solution in needle barrel
- Connect Syringe Handle and Local Anaesthetic needle with cartridge
- pull back safety sheath ready for use (clicks into place
- remove plastic needle cap
Injection technique for a buccal infiltration
- dry mucosa with cotton wool and apply topical anaesthesia on cotton wool (1-2 minutes)
- retract tissue with mirror and puncture mucosa with bevel facing towards bone
- needle should be parallel to the axis of the tooth and the needle should puncture the skin in the gingival sulcus adjacent to tooth that you want to be numb
- aim for the apex of tooth if you hit bone retract and reposition
- aspirate and deposit anaesthetic slowly (30s)
- massage anaesthetic and allow a few minutes for it to work (test)
- allow patient to rinse once distributing anaesthetic
Injection technique for a palatal infiltration
- dry mouth with cotton wool and numb with topical anaesthesia
- allow a few minutes for this to work
- select a short needle
- place the bottom end of your mirror in patients mouth and apply pressure behind the injection site
- aim for needle penetration 5-10mm palatally from the centre of the crown
- 45 degree angle to the long access of the tooth (parallel)
- advance until you hit bone and aspirate
- inject no more that 0.2-0.4ml or until you see blanching
injection technique for a IAN Block
- Dry with cotton wool and use topical anaesthesia to numb the injection site
- Thumb placed at coronoid notch and fingers cupping the angle of the mandible
- long Needle entry junction of buccal pad of fat / pterygomandibular raphe
- Syringe lies over contra lateral 5-6
- Advanced to bony contact (1cm of needle visible)
- If no bony contact reposition syringe distally
- If bony contact too soon, reposition syringe barrel mesially
- When in correct position withdraw from bony contact
- Aspirate
- Inject slowly
- For lingual anaesthesia withdraw while injection last 1/3 of solution
Injection technique for a mental nerve block
- numb area
- aim for between the apices of the lower premolars
- aspirate and then inject slowly
How would you gain consent for a LA?
“im going to be extracting your upper right 5 today so in order to do this i will have to numb up your tooth with local anaesthetic “ is that okay?