L115. An Overview of LA Techniques Flashcards
L115: What is pain?
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
L115: Why do we administer LA?
To manage pain
L115: What are the three main components of a LA?
- LA;
- Vasoconstrictor;
- Preservative.
L115: What are the two major types of LAs and of these, which ones are mainly used now?
Esters and amides
L115: What are the two major vasoconstrictors used in LAs?
- Adrenaline;
- Felypressin.
(or none!)
L115: What are the advantages of LAs containing vasoconstrictors?
- LA will stay in the area for a longer time;
- Controlled bleeding;
- Contributes to maintaining homeostasis;
- Bloodless field to work in.
L115: Which vasoconstrictor tends to be more effective for prolonging the LA at site?
Adrenaline
L115: What vasoconstrictor should be avoided if patients are pregnant or have heart conditions?
Felypressin
L115: What are the two major preservatives used in LAs?
- Bisulphite;
- Propylparaben.
L115: What are the advantages of LAs containing preservatives?
Prolonged shelf life
L115: Which LA preservative do people more commonly have an allergy to?
Propylparaben
L115: For patients with a true allergy to LA, where should they be treated?
Referred to anaphylactic clinic
L115: What are the two types of LA injections?
- Infiltration;
- Nerve block.
L115: How and where do infiltration LAs work?
- Used for pulpal anaesthesia where alveolar bone is thin;
- e.g. maxilla, lower anteriors and soft tissues;
- LA deposited around terminal branches of nerves.
L115: How and where do nerve block LAs work?
- Used for pulpal anaesthesia where alveolar bone is too thick to allow infiltration technique of LA administration;
- e.g. mandible, multiple teeth and large areas;
- LA deposited beside nerve trunk.
L115: When administered, nerve block LAs anaesthetise all nerve fibres x, to it?
Distal
L115: In the maxilla, pulpal anaesthesia is achieved by what type of LA injection?
Buccal infiltration
L115: In the maxilla, buccal gingivae anaesthesia is achieved by what type of LA injection?
Buccal infiltration
L115: In the maxilla, palatal gingivae anaesthesia is achieved by what type of LA injection?
Palatal injection
L115: In the mandible, anaesthesia of the molars ( + second premolar) is achieved by what type of LA injection?
Inferior dental block (IDB/ IAN)
L115: In the mandible, anaesthesia of the premolars ( + canine) is achieved by what type of LA injection?
Mental (incisive) nerve block
L115: In the mandible, anaesthesia of the canines and incisors is achieved by what type of LA injection?
Buccal/ labial infiltration
L115: In the mandible, buccal gingivae anaesthesia of the molars ( + second premolar) is achieved by what type of LA injection?
(Long) buccal infiltration
L115: In the mandible, buccal gingivae anaesthesia of the premolars ( + canine) is achieved by what type of LA injection?
Infiltration or long buccal or mental nerve block
L115: In the mandible, buccal gingivae anaesthesia of the canines and incisors is achieved by what type of LA injection?
Buccal/ labial infiltration
L115: In the mandible, lingual anaesthesia is achieved by what type of LA injection?
Secondary part of IDB, lingual infiltration
L115: If carrying out a restoration of a tooth, what type of LA is required?
Pulpal
L115: If carrying out an extraction of a tooth, what type of LA is required?
Pulpal and gingivae
L115: If scaling teeth, what type of LA is required?
- Gingivae;
- Pulpal;
- Both.
(depends on procedure!)
L115: What equipment is required to administer a LA?
- Syringe handle and bung;
- Syringe barrel and needle;
- LA cartridge.
L115: What are the two lengths of needles used in LAs?
- Short (25mm);
- Long (35mm).
L115: What must you check before using an LA cartridge?
Expiry date (record in notes along with batch number)
L115: In the UK, what is the typical volume of solution in one LA cartridge?
2.2mL
L115: In the UK, what is the typical ppm of adrenaline in one LA cartridge?
1 in 80,000
L115: In the UK, what are the three main LAs used in dentistry?
- Lignocaine (lidocaine);
- Articaine;
- Prilocaine.
L115: Which LA has been clinically shown to have increased ability to diffuse through bone?
Articaine
L115: Which LA is typically mixed with felypressin (vasoconstrictor), instead of adrenaline?
Prilocaine
L115: When checking a medical hx, what medical condition means that a patient cannot receive an IDB injection?
Haemophilia
L115: How should topical LA be applied?
- Dry mucosa (so that LA doesn’t dilute);
- Pea sized amount on cotton wool for 1-2 minutes.
L115: Why is it important to relax the patient and manage their anxiety?
- If stressed, more likely to feel pain;
- Breathing techniques and muscle relaxation can help to reduce the perception of pain.
L115: What typical injection technique should be used to administer a LA?
- Stretch mucosa;
- Puncture mucosa quickly;
- Position needle tip at target point;
- Aspirate;
- Inject slowly (min. 30 secs).
L115: Why is it important to aspirate?
To check whether you have entered a blood vessel or not, do not want to inject LA into blood vessel as will affect heart.
L115: Why must you inject LA slowly?
- To reduce pain;
- Too quick = high pressure;
- Can also cause damage to tissues.
L115: What are the limitations of infiltration anaesthesia?
- Pulpal anaesthesia limited to one or two teeth;
- Presence of dense bone/ infection may reduce the effectiveness.
L115: What are the positives of infiltration anaesthesia?
- High success rate;
- Technically easy;
- Atraumatic.
L115: What are the different parts of the alveolar nerve in the maxilla?
- PSA: posterior superior alveolar;
- MSA: middle superior alveolar;
- ASA: anterior superior alveolar.
L115: What sharps bin should an empty LA cartridge be discarded into?
Orange
L115: What sharps bin should an LA cartridge containing solution be discarded into?
Blue
L115: When administering an IDB, what landmarks do you use to identify the site of injection?
- Coronoid notch of the mandibular ramus;
- Posterior border of the mandible;
- Pterygomandibular raphe;
- Lower premolars of the opposite side.
L115: What is the pterygomandibular raphe?
Skin and connective tissue
L115: Why is it beneficial to ask the patient to open wide when administering an IDB?
- Tissue becomes taught;
- Can identify landmarks more easily.
L115: Describe the stages of administering a LA.
- Thumb on coronoid notch;
- Fingers on posterior border of the mandible;
- 3/4 of the way back between thumb and raphe;
- Advance needle until bone is contacted;
- 3/4 of needle should go in;
- Withdraw needle 1mm;
- Aspirate (check for blood);
- If negative, deposit 3/4 of cartridge;
- Retract 2-4mm of needle, deposit remaining 1/4 for lingual anaesthesia.
L115: If bone is not contacted when advancing the needle, what has most likely happened?
Needle positioned too posterior (reposition before injection)
L115: If you contact bone before 3/4 of the needle is advanced, what has most likely happened?
Needle positioned too anterior (reposition mesially before injection)
L115: What words can be used to describe a patient’s sensations when anaesthetised?
- Rubbery;
- Numb;
- Tingly;
- Swollen/ fat.
(with an IDB, this should extend to tongue and lower lip)
