Local Anaesthetics Theory - Part 2 PDF

Local Anaesthetics Theory – part 2 Tutor: Lucy Harrison Module: FCSP, Year 1 Key GDC learning outcomes 1.1.5 1.1.8 Describe relevant and 1.1.6...

Local Anaesthetics Theory – part 2 Tutor: Lucy Harrison Module: FCSP, Year 1 Key GDC learning outcomes 1.1.5 1.1.8 Describe relevant and 1.1.6 Describe the properties of appropriate dental, oral, Describe relevant and relevant medicines and craniofacial and general appropriate physiology and therapeutic agents and anatomy and explain their explain its application to discuss their application to application to patient patient management patient management management 1.7.4 Manage patient anxiety and 1.7.5 pain through effective Manage patient pain through communication, reassurance the appropriate use of and relevant behavioural analgesia techniques Aims and Objectives Deliver safe and effective local Describe and identify related oral anaesthesia to patients anatomy and nerve supplies To relate how to safely deliver infiltrations and IDBs Investigate the legal framework for LA delivery in dentistry Highlight the potential complications of LA delivery Nerve supply Patient preparation  Legal Valid prescription Any contraindications Medical History Has patient taken their medication Previous reactions to LA Has patient eaten as usual? Food Vaso-vagal attack prevention Why using LA- comfort/efficiency Explain Sensation Procedure LA anxiety/phobia PatientCalm atmosphere Distraction techniques Appropriate language Operator Positioning Visibility LA equipment What can affect the patients pain threshold?  Anxiety  Psychological makeup  Previous experience  Physical environment  Culture  Emotional state  Age  Distraction Hypnosis Gate Control Alternative theory stimulus Calm atmosphere Infiltrations  What nerves are we wanting to anaesthetise? Pterygopalatine nerves Positioning Patient supine, comfortable and well supported Patient at correct height for operator Light directed into sulcus area Application of topical anaesthetic agent Apply on Leave for Dry a cotton 2-3 mucosa wool roll minutes  Buccal infiltration technique 1. Estimate position of apex of the tooth 2. Pull surface mucosa taut Good Retraction Poor Retraction  Buccal infiltration technique 3. Insert needle through mucosa at 25 degrees to the bone 4. Aim for the apex of the tooth 5. Keeping roughly parallel to long axis of tooth Buccal infiltration technique 6. Smoothly allow needle to glide through taut mucosa Avoid contacting bone, if contacted withdraw 1-2mm Needle should be bevel to bone Buccal infiltration technique 7. Aspirate, especially if injecting around upper second/third molars Check cartridge Buccal infiltration technique 8. Deliver solution gently and low 9. Very little pressure required on the plunger 10. Withdraw needle smoothly 11. Make needle safe Buccal infiltration technique 0.5ml - 1ml of solution per site for infils for perio work 2.2ml of solution for restorations Pulpal analgesia should be established within 2-5 minutes Soft tissue analgesia 1-2 minutes WAIT Buccal infiltration technique Particular care required: Labial aspect of upper incisors – VERY SENSITIVE (use lots of topical and inject very slowly) Labial aspect of lower incisors – attachment of mentalis and depressor labii inferioris muscles Buccal infiltration video Supplementary Injections  Palatal infiltrations  Lingual infiltrations  Intrapapillary  Palatal Infiltration 1. Topical application/pressure on area first 2. Infiltrate the palatal mucosa of the appropriate tooth 3. Inject at 90 degrees to the mucosa at about 1-1.5cm from gingival margin half way between gingival margin and midline of palate 4. Considerable resistance IT CAN HURT A LOT 5. Deposit 0.2 ml of solution Palatal infiltration Used for:  Deep restorations  Subgingival PMPR (Professional Mechanical Plaque Removal)  Extractions of deciduous maxillary dentition Palatal infiltration video Intrapapillary Injection Useful for achieving palatal analgesia in children and nervous patients 1. Direct needle at right angles to interdental papilla 2. Insert needle into centre of papilla at level of attachment to periosteum 3. Deposit 0.25ml of solution 4. Check palatal mucosa has blanched Inferior Dental Block (IDB) Innervation of mandible Basic anatomy of the mandible RETROMOLAR FOSSA The pterygomandibular space  The facial nerve If needle goes in too deeply analgesic solution is deposited outside the pterygomandibular space in the deep lobe of the parotid gland. Facial nerve is blocked causing paralysis of the facial muscles Temporary facial palsy On which side of the mouth was the IDB administered? IDB Technique 1. Patient can be supine or upright (if large tongue or obese patient, try upright position) 2. Need good lighting 3. Ideally use topical analgesia 4. Patient’s mouth should be wide open to allow good visualisation of the anatomical landmarks 5. Sit in appropriate position to patient IDB Technique Select long needle 35 mm, 27 gauge  IDB Technique (1) and palpate external 6. Use finger or thumb to locate the retromolar fossa oblique ridge 7. Identify pterygomandibular raphe: (2) with finger or thumb (3) Look for ‘crease’ in mucosa between 1 and 2 (4) Point of entry is + IDB Technique 8. Position barrel of syringe over contra-lateral premolars. Correct level for mandibular foramen is identified by bisecting the thumb/fingernail and drawing an imaginary line 1cm above occlusal plane. IDB Technique 9. Insert needle smoothly and slowly into the pterygomandibular space, aiming for the mandibular foramen 10. Inject to a depth of 2.0-2.5 cm 11. Do NOT insert the full needle – 5mm of needle must ALWAYS be visible. 12. If mandibular bone is contacted, withdraw needle 1 mm and aspirate IDB Video IDB Technique- positive aspiration  If blood present upon aspiration  Withdraw needle 1 or 2 mm  Aspirate again  If no blood, continue with injection  If positive again, reposition and repeat aspiration IDB Technique 13. Once you are sure that the tip of the needle is not in a vein, then slowly deliver the anaesthetic solution 14. Withdraw needle quickly and smoothly and re-sheath needle to make it safe 15. Sit patient up for a rinse IDB makes yellow area numb.  Anatomical variations Bone struck too soon – withdraw, swing needle round to midline, advance for 7 mm, swing back to original position and proceed Electric shock sensation in tongue or lip means lingual nerve or mandibular nerve respectively touched by needle – must withdraw 1-2mm from mandibular nerve Incisive and Mental Block Useful if you want anaesthesia of several anterior teeth (incisors, canine and first premolar) Aim for mental foramen (between apices of first and second premolar) May provide unreliable anaesthesia for central incisor and may still need a lingual infiltration  Incisive and Mental block procedure 1. Check position of mental foramen on radiograph (if one available) 2. Patient ideally supine, good lighting 3. Apply topical LA 4. Ask patient to open wide 5. Unsheathe needle (30 gauge short) 6. Place tip of needle in reflection of buccal sulcus between root apices of LL4 and LL5 7. Aspirate- if not positive. Slowly inject at least 1ml solution 8. Withdraw needle and re-sheath safely  Do not give Articaine For IDBs OR Incisive and Mental block Needle stick injury Before contact with patient… No transfer of infection can occur if the needle has not contacted the patient  Double lock cover on needle  Remove gloves, wash with soap and dress wound if necessary  Inform senior tutor on clinic  New syringe/needle/cartridge and holder  New gloves No additional reporting needs to happen After contact with patient… Potential transfer of infection from patient to operator from the needle  Double lock cover on needle  Gloves off and WASH the wound under running water or rinse mucous membranes appropriately  Report to senior tutor on clinic  Check medical history to confirm if known blood-borne virus  Contact Occupational Health or A&E (out of hours) for advice  Patient blood sample  Record in notes  Datix incident report Link to Action Plan for a Sharps/Needlestick Injury Health and Safety Representative(s) (uclh.nhs.uk) Legal framework Who can change the LA agent? LA is a Prescription Only Medicine (POM) Need a written prescription for each specific agent from a recognised prescriber- a dentist The Human Medicines Regulations 2012 Patient group directive (PGD) – gives a legal framework that allows registered health professionals – including Dental Hygienists and Therapists to administer specified medicines without the need for a prescription What Constitutes a Prescription (Rx) for LA? Type of LA Route of Dosage Date Eg: Administration Eg: Check the Rx is Eg: One Cartridge in date for each Lidocaine Infiltrations 2.2 ml etc course of tx. Articaine IDB Notice to dental therapists and dental hygienists: legal change effective 26 June 2024 From 26 June 2024, an amendment to the Human Medicines Regulations made it possible for dental hygienists and therapists to supply and administer certain prescription-only medicines (POMs) under exemptions, without the need for a prescription from a dentist or a patient group direction (PGD). While specified medicines can legally be supplied and administered under exemptions, dental hygienists and dental therapists must undertake the appropriate training to ensure they are competent to use this new mechanism. There is no obligation for dental hygienists and dental therapists to administer and supply these medicines under exemptions. The changes do not give any prescribing powers to hygienists or therapists, or Post operative Post-injection precaution Never leave your patient alone after an injection A reaction may occur at any time  Including faint  Anaphylaxis Post- Operative Instructions Duration of Anaesthesia Usually, a few hours Avoid Hot food/drinks, biting lips/cheeks Do not poke/prod area With finger/tongue No smoking For duration of LA  Documentation of LA A dated signed entry must be made on the patient’s record every time LA is given:  Type of LA agent and vasoconstrictor  Amount of solution administered  Site of injection  Any unusual effects  Post operative instructions given verbally POIV LA - 2ml lidocaine 2% with epinephrine 1: 80,000, buccal infiltration UL7, UL4, UL2. POIGV Complication of LA Unwanted effects may occur as a result of:  Injecting an inappropriate solution  Injecting too much solution  Injecting into the wrong site Complications can be divided into: 1. Local 2. General Local complications Failure to go numb Most common complication  Flaccid Pain during injection Site of Too much No topical LA Blunt needle Too fast Too hot/cold Psychological mucosa injection solution Bleeding into the tissues following puncture of the Haematoma formation blood vessel May cause pain, trismus May become infected Intravascular injection systemic toxic effects failure of analgesia Skin blanching Due to vasospasm of artery Bleeding At point of injection Stops by itself Other Infection Lip/soft tissue trauma Trismus Visual disturbances Local complications Prolonged impairment of sensation SERIOUS COMPLICATION 1 in 14,000 IDBs cause permanent injury Seek help immediately Facial paralysis (IDB) Needle breakage Post anaesthetic reactivation of herpes simplex virus General complications  Psychogenic  Toxicity of LA agent  Overdose  Reduced tolerance  Intravascular adrenaline  Allergy- anaphylaxis  Drug interactions  Bleeding risk  ID blocks and lingual infiltrations may be contraindicated or used with caution depending on bleeding risk.  Risk relates to the act of injection, not the LA agent. Examples include patients with genetic bleeding disorders e.g. haemophilia  Patients taking anticoagulants or antiplatelet drugs e.g. warfarin, clopidogrel  Alcoholics (reduced liver function)  Patients with liver disease.  Failure of anaesthesia  Too long a delay before commencing treatment  Too little solution administered  Intravascular injection (aspirate)  Inaccurate placement of needle point (IDBs)  Anatomical variations  Incorrect choice of technique  Anxiety/fear/negative experience  Poor storage of LA (too hot/ in sunlight) Presence of infection Never inject into an area of inflammation/infection Inject mesial and distal to the area If LA fails… Don’t overdose Get advice Summary Today we have…  Described and identified related oral anatomy and nerve supplies  Understand how to safely deliver infiltrations and IDBs  Investigated the legal framework for LA delivery in dentistry  Highlighted the potential complications of LA delivery Any questions? Reference List Evers, H. (1990) Introduction to Dental Local Anaesthesia. 2nd Edition. Switzerland: Mediglobe SA. Yapp, K.E., Hopcraft, M.S. and Parahos, P., (2011) Articaine: a review of the literature, British Dental Journal volume, 210, pp. 323–329. Available from: https://www.nature.com/articles/sj.bdj.2011.240 [Accessed on 5th January 2023].