La revision
- 1. LA REVISION - I Dr.V.RAMKUMAR CONSULTANTDENTAL&FACIOMAXILLARYSURGEON REGNO:4118 TAMILNADU-INDIA(ASIA)
- 2. Local anesthesia has been defined as a loss of sensation in a circumscribed area of the body caused by a depression of excitation in nerve endings or an inhibition of the conduction process in peripheral nerves.
- 3. Properties deemed most desirable for a LA solution – It should not be irritating to the tissue. It should not cause any permanent alteration of nerve structure. Its systemic toxicity should be low. It must be effective regardless of whether it is injected into the tissue or applied locally to mucous membranes.
- 4. The time of onset of anesthesia should be as short as possible. The duration of action must be long enough to permit completion of the procedure. It should be relatively free from producing allergic reactions. It should be stable in solution and readily undergo biotransformation in the body.
- 5. Electrophysiology of nerve conduction
- 6. Exitation of nerve segment leads to an increase in permeability of the cell membrane to Na ions At firing threshold permeability increases dramatically
- 7. Reversed polarity Repolarization (the action potential is terminated)
- 8. Mode and site of action of LA LA interfere with the excitation process in a nerve membrane in one or more of the following ways Altering the basic resting potential of the nerve membrane Altering the threshold potential (firing level) Decreasing the rate of depolarization Prolonging the rate of repolarization
- 9. Where do local anesthetics work? Various theories – Acetylcholine theory Calcium displacement theory (most popular) Surface charge (repulsion) theory Membrane expansion theory Specific receptor theory
- 10. How LA work?
- 11. Ca++ which exist in bound form within the cell membrane are thought to exert a regulatory role on the movement of Na+ ions Displacement of Ca++ ions from the Na+ channel receptor site Ca++ Ca++ Ca++ Ca++
- 12. Binding of LA molecule to this receptor site produces – Blockade of the Na+ channel – and results in conduction blockade
- 14. Classification of LA 1…Esters Benzoic acid Paraaminobenzoic acid Butacaine Cocaine Ethyl aminobenzoate (benzocaine) Hexylcaine Piperocaine Tetracaine Chlouopeocaine Procaine Propoxycaine
- 15. 2…Amides Articaine Bupivacaine Dibucaine Etidocaine Lidocaine Mepivacaine Prilocaine Ropivacaine 3…Quinoline Centbucridine
- 16. Half life of LA Lidocaine – 1.6 hours Bupivacaine – 3.5 hours
- 18. Vasoconstrictors are drugs that constrict blood vassals. Advantages – Decreases blood flow to the site of administration. Absorption of LA into the CVS is slowed. Minimizing the risk of LA toxicity. Increasing the duration of action of LA.
- 19. Classification Catecholamines Noncatecholamines Epinephrine Amphetamine Norepinephrine Methamphetamine Levonordefrin Phenylephrine Felypressin (vasoconstrictor), a synthetic analogue of the polypeptide vasopressin.
- 20. Maximum doses of LA Lidocaine with epinephrine 7 mg/kg of body weight for the adult (not to exceed a dose of 500 mg). Lidocaine without epinephrine 4.4 mg of body weight for the adult (not to exceed a dose of 300 mg). Same dose for children.
- 21. Calculation of number of cartridges (for70 kg) Lidocaine with epinephrine According to manufacturer – 20 mg/ml i.e. in 1 ml - 20 mg Considering cartridge as 1.8 ml i.e. in 1.8 ml - 36mg(1.8×20) or in 1 Cartridge - 36 mg Not to exceed a dose of 500 mg So total no of cartridges 500/36 = 13.88 cartridges
- 22. Lidocaine without epinephrine According to manufacturer – 20 mg/ml i.e. in 1 ml - 20 mg Considering cartridge as 1.8 ml i.e. in 1.8 ml - 36mg(1.8×20) or in 1 Cartridge - 36 mg Not to exceed a dose of 300 mg So total no of cartridges 300/36 = 8.33 cartridges
- 23. Armamentarium
- 24. Tow types of armamentarium Major components Syringe Needle Cartridge Other components Topical antiseptic Topical anesthetic Applicator sticks Cotton gauze (2×2 inches) Hemostat
- 25. Syringe – It is the vehicle whereby the contents of the anesthetic cartridge are delivered through the needle to the patient.
- 26. Needle – The needle permits the local anesthetic solution to travel from the dental cartridge into the tissues surrounding the needle tip.
- 27. Cartridge – Is a glass cylinder containing the local anesthetic drug.
- 28. Topical anesthetic -
- 29. Applicator sticks –
- 30. Cotton gauze (2×2 inches) –
- 31. Hemostat –
- 32. LA REVISION – II
- 33. Types of Local anesthetic injection Local infiltration – Small terminal nerve endings in the area of the dental treatment are flooded with local anesthetic solution. Example: administration of LA into an interproximal papilla.
- 34. Field block – LA solution is deposited near the larger terminal nerve branches so the anesthetic area will be circumscribed.
- 35. Nerve block – LA is deposited close to a main nerve trunk.
- 36. Common Techniques of Anesthesia (Maxillary / Mandible) 1…Supraperiosteal (infiltration) 2…Periodontal ligament injection (intraligamentary injection)
- 37. 3…Intraseptal
- 39. Techniques of maxillary anesthesia Posterior superior alveolar nerve block
- 40. Infraorbital nerve block
- 41. Middle superior alveolar nerve block Is present in only about 28% of the population
- 42. Palatal anesthesia Greater palatine nerve block
- 43. Nesopalatine nerve block
- 44. Techniques of mandibular anesthesia Inferior alveolar nerve block
- 45. Lingual nerve block – After depositing LA solution for inferior alveolar nerve pull the needle half way out, aspirate and deposit the LA solution for lingual nerve Advantage – nicking of soft tissue will be avoided.
- 46. Buccal nerve block – a. Parallel with occlusal plane on the side of injection but buccal to it. b. Distal and buccal to the last molar.
- 47. Mental nerve block
- 48. Mandibular nerve block: the GOW-GATES technique
- 49. VAZIRANI-AKINOSI closed-mouth mandibular block
- 50. Complications of local anesthesia Local complications Needle breakage Persistent anesthesia or paresthesia Facial nerve paralysis Trismus Soft-tissue injury Hematoma Pain on injection Burning on injection Infection Edema Sloughing of tissues Post-anesthetic intraoral lesions Systemic complications Vasodepressor syncope Over dosage (toxic reaction) Allergy Psychogenic reactions
- 52. Needle breakage Causes – Weakening of the dental needle by bending it before it’s insertion. Sudden unexpected movement by the patients. Prevention – Use a 25-gauge needle. Use long needle requiring penetration (> 18 mm).
- 53. Persistent anesthesia or paresthesia Causes – Trauma to any nerve. Injection of contaminated LA solution. Hemorrhage into or around the neural sheath (Bleeding increases pressure on the nerve) Prevention – Strict adherence to injection protocol. Proper care and handling of dental cartridges.
- 54. Causes – Transient facial nerve paralysis is commonly caused by the introduction of LA into the capsule of the parotid gland. Prevention – Adhering to protocol with the IANB . A needle tip should be in contact with the bone. Management – Reassure the patient Contact lance should be removed An eye patch should be applied to the affected eye. “tincture of time” is the recommended medicine.
- 55. Trismus Causes – Trauma to muscles or blood vessels. Contaminated LA solution. Hemorrhage. A low grade infection. Excessive volumes of LA solution. Prevention – Practice atraumatic insertion and injection technique. Management – Heat therapy, physiotherapy. Warm saline rinses. Anti-inflammatory, Analgesics, Muscle relaxants, Antibiotics.
- 56. Soft-tissue injury Causes – Common in younger children and mentally or physically disabled children or adults. Prevention – Proper instruction and education of guardian
- 57. Hematoma Causes – The effusion blood into extravascular spaces due to nicking of blood vessel (artery or vein) during injection. Prevention – Use a short needle for PSA nerve block. Minimize number of needle penetration. Management – Direct pressure should be applied to the site of bleeding. Do not apply heat to the area for at least 4 to 6 hours.
- 58. Pain on injection Causes – Careless injection technique. Prevention - Proper technique. Use of sharp needle. Use of topical anesthetic. Inject LA slowly.
- 59. Burning on injection Causes – pH of the solution (pH = 5 acidic) Rapid injection of LA. Contamination of LA cartridges Prevention – Slowing the injection ( ideal rate 1 mm per sec.)
- 60. Infection Causes – Contamination of needle. Injecting LA solution into an area of infection. Management – Rx treatment consist of those procedures to manage Trismus.
- 61. Edema Swelling of tissue is a clinical sign of the presence of some disorder. Causes – Trauma, Infection, Allergy, Hemorrhage. Prevention – Complete medical evaluation of the patient before drug administration.
- 62. Sloughing of tissues Prolonged irritation or ischemia of gingival soft tissue may led to – Epithelial desquamation Sterile abscess
- 63. Post-anesthetic intraoral lesions These are recurrent aphthous stomatitis and Herpes simplex. Management – Primary management is symptomatic.
- 64. Systemic complications Vasodepressor syncope Over dosage (toxic reaction) Allergy Psychogenic reactions
- 65. Thank You