Overview of LA techniques in Dentistry Flashcards
List uses of LA (5)
- Dental implants
- Extracting teeth for endo procedures
- Crown preps
- Fillings with rubber dams
- Scaling
Define pain
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
List the different types of LA (2)
- Ester
2. Amide
List the different vasoconstrictors used in LA (3)
- None
- Adrenaline
- Felypressin/Octapressin
List the preservatives used in LA (2)
- Bilisulphite
2. Propylparaben
Function of vasoconstrictors (2)
- Cause bv’s to constrict, prolongs effect of LA
- Control bleeding with haemostasis
- Helpful for managing bleeds for surgical/restorative point of view
Function of preservatives
Prolong shelf life
What component of LA are most people allergic to?
Adrenaline
How do we avoid inserting LA into a BV? (3)
> Aspirate to ensure the LA hasn’t been placed in a BV
If situated in a BV you must move it as the patient may experience an increased HR
Dangerous for patients who take drugs like cannabis/cocaine
Name a disadvantage of alternative vasoconstrictors (1)
Not as effective at retaining LA in the area
When should octapressin be avoided?
Avoid during pregnancy
Can induce labour
What preservative can lead patients to believe they have allergy issues?
Propylparaben
- Increased HR effects
What is the most popular type of LA injection?
Infiltration
Where is LA deposited in an infiltration injection
Around terminal branches of nerves
The purpose of infiltration
To anaesthetise soft tissues
Where is infiltration used?
To produce pulpal anaesthesia where alveolar bone is thin
- Maxilla
- Lower anteriors
Why can infiltration not be used when the alveolar bone is thick?
The LA solution has to be able to get through the bone to achieve successful pulpal anaesthesia
Bone is thin in the maxilla (allowing easier access to roots of the teeth) so the LA can penetrate through this bone easily
The bone in the posterior aspect of mandible is much thicker
What part of the mandible has thinner bone?
Thinner in the lower anterior aspect of the mandible
What LA can be used to inject posteriorly in the mandible?
Articaine
Function of a nerve block and where it is deposited
- Used to produce soft tissue anaesthesia
- Anaesthetic deposited beside the nerve trunk leads to abolished sensation distal to the site
When is a nerve block used?
- Used when bone is too thick to allow infiltration (i.e. mandible)
- Can be used when working on multiple teeth/on a large area as it minimises the amount of time you must puncture the mucosa
- Reducing anxiety around piercing and pain
- Don’t want to puncture often for those with haemostastic issues
List the LA’s that can be used in the maxilla (2)
- Buccal infiltration
2. Palatal injection
Compare infiltration and nerve block (4)
INFILTRATION
- LA deposited around terminal branches of nerves
- Only these nerves will be anaesthetised by LA
NERVE BLOCK
- LA deposited beside nerve trunk
- Within that area ALL the fibres distal to this site are covered by LA (larger spread)
What LA is used for the dental pulp in the maxilla?
Buccal infiltration
What LA is used for the buccal gingivae in the maxilla ?
Buccal infiltration
- Good for scaling/extracting teeth
- Vasoconstrictor helps decrease bleeding
What LA is used for the palatal gingivae in the maxilla?
Palatal injection
List LA’s that can be used in the dental pulp of the mandible (3)
- IAN
- Mental (incisive) nerve block
- Buccal/labial infiltration
List LA’s that can be used in the buccal gingivae of the mandible (4)
- (Long) buccal infiltration
- Infiltration
- Mental nerve block
- Buccal/labial infiltration
Where is IAN used in DENTAL PULP of the mandible? (2)
- Molars
- 2nd premolar
When is mental incisive nerve block used in DENTAL PULP of the mandible?
- Premolars
- Canine
Why is the use of the mental incisive nerve block population dependent?
- Within the Chinese population the mental nerve is situated further back within the mandible in comparison to rest of population
- Palpate for mental nerve so know where to deposit it
When is buccal/labial infiltration used in DENTAL PULP of the mandible?
- Canines
- Incisors
When is a (long) buccal infiltration used in the BUCCAL GINGIVAE of the mandible?
- Molars
- 2nd premolar
used alongside IAN as gingivae is supplied by the buccal nerve so need additional cover
When is
- Infiltration
- Mental nerve block
Used in the BUCCAL GINGIVAE of the mandible?
- 1st premolar
- Canines
When is buccal/labial infiltration used in the BUCCAL GINGIVAE of the mandible?
- Incisors
- Canines
What LA technique is used for the LINGUAL GINGIVAE in the mandible? (2)
- Secondary part of inferior alveolar end block given
2. Lingual infiltration
Why is it useful to withdraw 2-3mm when giving an IAN block?
Means you capture the lingual nerve too (which supplies the tongue on that side) so hit 2 nerves in one injection
- IAN
- Lingual nerve
When is lingual infiltration used? (3)
- Possibility for anterior aspect of the mandible
- Used posteriorly if needed as a top up for additional anaesthesia
- Endo procedures
What tissue is anaesthetised for the restoration of a tooth?
Dental pulp
What tissue is anaesthetised for an extraction?
Dental pulp
Gingivae
What tissue is anaesthetised for scaling?
Gingivae OR pulp and gingivae?
As if you are root planing on dentine it can be quite tender and sore
List the equipment that makes up LA (4)
- Syringe handle + rubber bung
- Syringe barrel (diff lengths)
- Cartridge of LA
- Make sure to check expiry date + batch for traceability reasons
State the length of syringe barrel used for infiltration
Short 25mm
State the length of syringe barrel used for IAN
Long 35mm
List examples of Local anaesthetic types used in dentistry (3)
- Lignocaine
- Articaine
- Citanest
How is rubber bung attached to the syringe handle?
Insert with wider end towards the handle
How is the LA needle assembled? (5)
- Cartridge of LA placed inside needle
- Syringe handle pressed into cartridge
- Safety mechanism- pull part of needle back, pull cap away and dispose
- Pull back down for 1 click (can be put down and pulled back later)
- If 2 clicks, is locked and can no longer be used
Adrenaline content in lignocaine
1:80,000
Adrenaline content in articaine
1:100,000
List advantages of articaine (3)
- Increased ability to diffuse through bone
- Don’t need to give IAN with it, can just use articaine + infiltration
- Not processed in liver so good alternative for those with liver disease that don’t want extra pressure on it
State an advantage of Citanest (with octapressin)
For those who don’t like adrenaline effects
List the steps involved for prepping a patient for LA (4)
- Check medical history
- If haemophiliac can’t give them IDB - Position in chair
- Dictated by what type of tx
- Most given with pt sitting upright for infiltration and blocks - Dry mucosa
- As if moist the topical anaesthesia will dilute and reduce efficacy - Apply a pea size amount of topical for 1-2mins on cotton wool
Why are most LA’s given sitting up?
Anatomy + reference points are much clearer
Justification for lying them down = if patient becomes hypertensive or faint they are already on their back
State the role of the bevel in an LA
Provide a cutting surface that offers little resistance to mucosa as the needle penetrates
Describe the injection technique for LA (4)
- Stretch mucosa (puncture it quickly)
- Position needle tip at target point
- Aspirate
- Safety plus mechanism for self aspirating - Inject slowly (no less than 30 secs as fast upregulates pain)
What is the correct bevel orientation required?
Bevel towards you during needle placement means the lumen is not obstructed
What is the point of the safety plus mechanism? (2)
- If blood enters, you’ve hit a blood vessel and you need to retract
- Take a new cartridge and start again (if you don’t replace cartridge, you won’t be able to ensure that you’ve avoided a BV the 2nd time)
Needle position for infiltrations (2)
- Bevel away from bone or you will penetrate periosteum
2. Periosteal injections are more likely to evoke a painful response
Needle position for IAN block
Makes no difference
How is an injection site identified for a buccal infiltration?
Identify the injection site in reflection of mucosa below the apex of the tooth
How is pulpal (infiltration) anaesthesia limited?
Limited to 1 or 2 teeth
- Infection
- Dense bone (may not be able to achieve anaesthesia there so need Articaine)
Advantages of pulpal (infiltration) anaesthesia
- High success rate
- Technically easy
- Atraumatic
Buccal infiltration technique (7)
- Stretch cheek and puncture mucosa with correct bevel of needle
- Advance needle until over the apex of the tooth
- If bone is contacted, withdraw slightly
- Aspirate
- If negative inject slowly
- If positive, reposition and repeat - Remove syringe from mouth and slide sheath down to 1st click
- Massage LA into tissues
- Wait 2 minutes for anaesthesia then test area
List blocks used in the maxilla (3)
- PSA
- MSA
- ASA
Where is PSA used in the maxilla?
Pulpal anaesthesia for 1st, 2nd and 3rd molars
Where is MSA used in the maxilla?
Canine
Premolars
1st molar
When is bone more likely to be contacted?
In the maxillary and premolar area as there are more boney prominences
Where is ASA used in the maxillary
Incisors
Canines
Areas for disposal of
- Rubber bung
- LA needle
- Clinical waste
2. Orange sharps bin (if it has contents then blue lidded sharps bin)
Examples LA injections performed as buccal infiltrations (2)
- Mental block
- Administer between apices of lower premolars, DO NOT put needle into foramen - Buccal injection
- Administer slightly distal to tooth being treated
Limitations of IAN block (2)
- Increased onset time
2. Increased lingual nerve injury
IAN block positioning technique (5)
- Thumb placed at anterior notch
- Needle entry junction of buccal pad of fat/pterygomandibular raphe
- Syringe lies over the contra-lateral 5-6
- Advanced until you hit bone (1cm of needle visible)
- If no bony contact reposition the syringe distally
What to do if you hit bone too soon with your IAN block (4)
- Reposition syringe barel mesially
- When in correct position withdraw from bony contact
- Aspirate
- Inject slowly, for lingual withdraw wile injection last 1/3rd of solution
Why should 1cm of the needle remain after the injection?
So that if the needle breaks it can be easily removed
List the important landmarks for an IAN block (4)
- Thumb on coronoid notch of mandibular ramus
- Fingers on posterior aspect of the mandible
- Barrel of syringe situated on the contralateral premolars
- Mandibular foramen is the site of anaesthetic deposition
List ways of confirming anaesthesia (4)
Ask the patient how it feels
- Rubbery
- Numb
- Tingly
- Swollen/fat
List ways of confirming anaesthesia for an IAN block (2)
- Tongue and lower lip extending to the midline on that side should feel different
- Ability to sense pressure remains but no pain
What can be used to test the mucosa for LA before an extraction/ an oral surgical procedure
Test the mucosa with a probe
