Local Anesthesia Lecture Notes PDF

LOCAL ANESTHESIA MOHAMED ABDELHALEEM A Lecture contents: Objective introduction Types of thyroid gland diseases Diagnosis Complications Treatment dental management Oral/Orofacial manifestations The issues Aims: Learning outc...

LOCAL ANESTHESIA MOHAMED ABDELHALEEM A Lecture contents: Objective introduction Types of thyroid gland diseases Diagnosis Complications Treatment dental management Oral/Orofacial manifestations The issues Aims: Learning outcomes //////////// /////// AIMS: LEARNING OUTCOMES Learning outcomes : Upon completion of this local anesthesia course, the student will be able to: 1. Understand the theoretical, practical and pharmacological aspects of local anesthesia. 2. Evaluate a patient's medical history, physical status, indications and contraindications for the use of local anesthesia. 3. Identify and locate the anatomical structures related to the administration of local anesthesia. 4. Gain clinical proficiency in the administration of the differents types of injections. 5. Recognize and manage any adverse reactions and medical emergencies related to the administration of local anesthesia.  INTRODUCTION Many dental operations and procedures such as extraction , major oral surgery and often cavity 2 USES OF LOCAL ANESTHESIA: preparation are both painful and prolonged and nowadays all these procedures are performed 3 INDICATIONS OF LOCAL ANESTHESIA without pain by the using of local anesthesia.  Pain: - unpleasant physical sensation experienced followed the application of noxious stimuli; although the supporting tissues of the teeth can themselves INTRODUCTION give rise to pain most of the nerve endings in the periodontal membrane are properioceptive. 2 USES OF LOCAL ANESTHESIA: Anesthesia: - means loss or abolition of all modalities of sensation which includes pain and touch. 3 INDICATIONS OF LOCAL ANESTHESIA Analgesia: means loss of pain sensation only. Parasthesia: - means altered sensation (tingling sensation} and this may occur when a damaged nerve is regeneration or when a local anesthesia is either  Relative analgesia:- is a sedation technique in which the patient remains conscious but mental relaxation is induced by inhalation of a mixture INTRODUCTION nitrous oxide, oxygen and air. local anesthesia used when necessary. 2 USES OF LOCAL ANESTHESIA: Depolararizatson : - when a stimulus excites a nerve this will lead to an increase in 3 INDICATIONS OF LOCAL ANESTHESIA permeability of the membrane to Na ions ,the rapid influx of Na ions to the interior of the nerve will cause depolarization of the nerve membrane from the resting level to its firing threshold.  the Local anesthesia (L.A ): could be defined as a loss of sensation in a INTRODUCTION circumscribed area of the body caused by a depression of excitation In nerve ending or Inhibition USES OF LOCAL ANESTHESIA: of the conduction process in peripheral nerves. 2 An important feature of local anesthesia is 3 INDICATIONS OF LOCAL ANESTHESIA that it produces this loss of sensation without inducing loss of consciousness. In this one major area, local anesthesia differs dramatically from general anesthesia.  Local anaethetic agents : üare drugs that block nerve conduction when applied locally to nerve tissue inappropriate INTRODUCTION concentration. üacton all types of nerve fibers,sensory or 2 USES OF LOCAL ANESTHESIA: motor ü it affects the axonal membrane of periphera 3 INDICATIONS OF LOCAL ANESTHESIA nerve General anaesthetics :act on the synaps of central nervous system  General anaestheia : is the loss of all forms of sensations with the loss of motor reflexes and loss INTRODUCTION of consciousness. In dentistry , only loss of pain sensation is desirable 2 USES OF LOCAL ANESTHESIA: (analgesia) Analgesia : it is loss of pain sensation without loss 3 INDICATIONS OF LOCAL ANESTHESIA of other sensations and without loss of consciousness. Analgesia is apart of anaesthesia  Many methods are used to induce local anesthesia 1- Mechanical trauma (compression of tissues) 2- Low temperature INTRODUCTION 3- Anoxia or hypoxia 4- Chemical irritants 2 USES OF LOCAL ANESTHESIA: 5- Neurolytic agents such as alcohol and phenol 6- Chemical agents such as local anesthetics 3 INDICATIONS OF LOCAL ANESTHESIA -However, only those methods or substances that induce a transient and completely reversible state of anesthesia have application in clinical practice  The effect of a local anesthetics on nerve fiber has been shown to be dependent on : - INTRODUCTION 1- The duration of exposure of local anesthesia. 2 USES OF LOCAL ANESTHESIA: 3 INDICATIONS OF LOCAL ANESTHESIA 2- Concentration. 3- Volume of the solution.  Uses of local anesthesia: 1 INTRODUCTION Ødiagnostic uses ØTherapeutic uses: 2 Uses of local anesthesia Øpreoperative uses Øpostoperative uses 3 Indications of local anesthesia  a- diagnostic uses administration of (t. A) can be a useful way of finding the source of patients pain an example of this is the pain of pulpitis which can be very difficult for both the patient INTRODUCTION and the dentist to isolate because of its tendency to be 1 referred to other parts of the mouth or face, so (L. A ) can distinguish between maxillary and mandibular sources, 2 Uses of local anesthesia and even between individual upper teeth provided they are not immediately adjacent ,another example is a patient with myofacial pain who is convinced that an 3 INDICATIONS OF LOCAL ANESTHESIA upper tooth is causing the problem ( L. A) may help this patient and the surgeon in this situation to eliminate the tooth as the cause of pain and may thus avoid its un necessary treatment.  B- Therapeutic uses: (L. A) can in themselves constitute part of a treatment for painful surgical conditions, for 1 INTRODUCTION example the use of block technique to eliminate the pain of dry socket can be helpful to the management of this very painful 2 Uses of local anesthesia condition particularly in the first few days. Blocks of the inferior dental nerve, mental 3 INDICATIONS OF LOCAL ANESTHESIA nerve ,or infraorbital nerve can also be used for the treatment of trigeminal neuralgia when pain breakthrough.  c- preoperative uses the provision of pain - free operative surgery is by far the most common use of (L. A ) and 1 INTRODUCTION provides effective and safe method for almost all outpatient dentoalveolar oral surgical procedures, it can in conjunction with sedation 2 Uses of local anesthesia techniques allow more difficult procedures to be carried out with out the additional risks of 3 INDICATIONS OF LOCAL ANESTHESIA general anesthesia and this is particularly of value in patients with significant cardio - vascular or air way diseases.  c- preoperative uses con. Additionally however, (L. A ) Is often given to patients undergoing oral and maxillofacial surgery under general anesthesia this serves the following purposes 1 INTRODUCTION 1-It reduce the depth of general anesthesia needed 2 Uses of local anesthesia 2- It reduce the arrhythmia which are noted on electrocardiogram during the surgery when 3 INDICATIONS OF LOCAL ANESTHESIA significant stimulation is taking place /this can be seen for example when a tooth is being elevated 3-It also provides local homeostasis to the operative site and provides immediate postoperative analgesia.  D- postoperative uses: After surgery with either local or 1 INTRODUCTION general anesthesia the continuing effect of the anesthesia is a most 2 Uses of local anesthesia beneficial way of reducing patients discomfort ,it help to reduce or even 3 INDICATIONS OF LOCAL ANESTHESIA eliminate the need for stronger systemic analgesic.  Indications of local anesthesia:- Local anesthesia is indicated in almost all the dental procedures, 1-It is used to render the teeth and supporting tissue INTRODUCTION and structures insensitive to painful procedures. 2- It is used in oral surgery for extraction of teeth and 2 Uses of local anesthesia fractured roots, and for all other surgical procedures as surgical removal of teeth, apicoectomy, incisions and 3 INDICATIONS OF LOCAL ANESTHESIA:- drainage of localized abscesses, removal of cysts. ranula and salivary calculi, and for all other surgical procedures.  Indications of local anesthesia:- con. 3- Local anesthesia is used also for the conservative INTRODUCTION treatment as for cavity preparation , crown and bridges abutment preparation , pulp treatments as root canal filling, pulpotomy or pulpectomy. 2 USES OF LOCAL ANESTHESIA 4- Local anesthesia is used for the surgical treatment of the periodontal diseases, deep scaling and prophylaxis 3 INDICATIONS OF LOCAL ANESTHESIA:- treatment ,mucogingival surgical procedures. it is also used some time in prosthodontic treatment and some of the orthodontic treatments 4 CONTRA INDICATIONS OF Contraindications of local anesthesia LOCAL ANESTHESIA These can be divided into two groups : 5 ADVANTAGES OF FOCAL ANESTHESIA 1 Absolute contraindications DISADVANTAGES OF FOCAL 2 -Relative contraindications : 6 ANESTHESIA  1 Absolute contraindications such as A - history of allergy to local anesthetic agent ØLocal anesthetic agents related to the same chemical group should not be used however , local anesthetic 4 CONTRA INDICATIONS OF agents in the different chemical group can be used. In LOCAL ANESTHESIA case, a patient gives history of allergy to an amide ADVANTAGES OF FOCAL ANESTHESIA local anesthetic agent , an ester local anesthetic local 5 anesthetic agent can be used. B-documented allergy to other constituents of the local 6 DISADVANTAGES OF FOCAL ANESTHESIA anesthetic solution When the patient has a history of allergy to any of the constituents of the local anesthetic solution the solution containing the constituent should be avoided , an alternate solution should be used , if possible.  2 -Relative contraindications : A - fear and apprehension : where the patient is CONTRA INDICATIONS OF uncooperative or refuse for the local anesthesia. 4 LOCAL ANESTHESIA B - presence of acute Inflammation or suppurative ADVANTAGES OF FOCAL ANESTHESIA infection at the site of insertion of the needle where 5 their will be increase chances for the spread of infection with the passages of the needle from the 6 DISADVANTAGES OF FOCAL ANESTHESIA abscess area to the deeper tissue. C - infant or small children : these patients lack reasoning and understanding  2 -Relative contraindications con. : D- mentally retarded patients : these patients are unable to cooperate. 4 CONTRA INDICATIONS OF LOCAL ANESTHESIA E -patient with significant medical disease as cardiovascular disease ,hepatic dysfunction , renal 5 ADVANTAGES OF FOCAL ANESTHESIA dysfunction , and clinical hyperthyroidism. F - restricted mouth opening : when the patient DISADVANTAGES OF FOCAL 6 ANESTHESIA cannot open his mouth sufficiently, in situations such as trismus, also in partial or complete ankylosi of the temporomandibular joint. H - major surgical procedures.  Advantages of focal anesthesia CONTRA INDICATIONS OF LOCAL 1- No special preparation of the patient is needed 4 ANESTHESIA 2- No complicated apparatus or bulky gas cylinders are needed 5 ADVANTAGES OF FOCAL ANESTHESIA 3- There is no risk of respiratory obstruction 6 DISADVANTAGES OF FOCAL 4- Anesthesia duration for at least an hour ANESTHESIA 5- The patient remains a wake and cooperative and need no after care  Advantages of local anesthesia CONTRA INDICATIONS OF LOCAL 6- Seriously ill patient such as those with heart 4 ANESTHESIA disease can usually tolerate local anesthesia without any risk. 5 ADVANTAGES OF FOCAL ANESTHESIA 7- An anesthetist and other additional trained personnel not required. DISADVANTAGES OF FOCAL 6 ANESTHESIA 8- Technique is not difficult to master, A 9- Percentage of failure is small. 10- No additional expense to the patient  Disadvantages of focal anesthesia No true disadvantages to the use of local CONTRA INDICATIONS OF LOCAL 4 ANESTHESIA anesthesia when the patient Is normal and there is no contraindications to its use so in 5 ADVANTAGES OF FOCAL ANESTHESIA every instance when satisfactory anesthesia can be achieved and the patient is 6 DISADVANTAGES OF FOCAL ANESTHESIA cooperative, local anesthesia is the method of choice.  Component (content) of L.A cartidge: 1 local anesthetic drug or agent 7 PHARMACOLOGY OF LOCAL ANESTHESIA 2. vasoconstrictor drug 3. Antioxydent/reducing agent 8 4. Preservative/bacteriostatic 9 5. Ringer's solution 6. Fungicidal 7. distilled water  Component (content) of L.A cartridge: 1 local anesthetic drug or agent Local anesthetic drugs ( agents ): 7 PHARMACOLOGY OF LOCAL ANESTHESIA Local anesthetics are drugs which upon topical 8 application or local injection cause reversible loss of sensory perception , especially of pain in 9 a restricted area of the body , it provides pain control during dental therapy , it interrupts propagation of impulse preventing it from reaching the brain.  Component (content) of L.A cartridge: 1 local anesthetic drug or agent Properties of an ideal local anesthetic agent A - potency and reliability : - the first requirement of such a substance is that when administered correctly and in 7 PHARMACOLOGY OF adequate dosage it consistently produces effective local LOCAL ANESTHESIA anesthesia. B - reversibility of action : - the action of any drugs used 8 to obtain local anesthesia must be completely reversible within a predictable time. C - safety : - all local anesthetic agent must have a wide 9 margin of safety from the poisonous side-effects which are collectively known as toxicity. D - lack of irritation : - no injury to or irritation of the tissues should result from the injection of a local anesthetic agent. For this reason local anesthetic solutions should be isotonic and have a PH compatible with that of the tissues.  Component (content) of L.A cartridge: 1 local anesthetic drug or agent Properties of an ideal local anesthetic agent E-Rapidity of onset (Ionization) The pKa of local anesthetic determine it’s speed of action.The closer pKa of local anesthetic is to 7 PHARMACOLOGY OF LOCAL the PH of tissue(7.4), the more rapid the onset. ANESTHESIA (PROPERTIES) F - duration of effect: the degree of protein binding of local anesthetic agent determine the duration of anesthetic.A 8 greater degree of protein binding at the receptor site will create a longer duration of anesthetic.bupivacaine, tetracaine 9 and etidocaine are all highly protein bound, they are long- acting local anesthetic. Vasoconstrictors will also determine the duration of L.A. G- penetration of mucous membrane : - ideally the drug should have the property of penetrating mucous membrane. H-sterility  Component (content) of L.A cartridge: 1 local anesthetic drug or agent 7 PHARMACOLOGY OF LOCAL ANESTHESIA (CLASSIFICATION) Classification of local anesthetics Aspect: 8 They differ in two impotant aspects 1. Their ability to induce hypersensitivity reaction 9 2. Thier pharmacokinetics-fate and metabolism Amides Esters long acting short acting metabolized by liver enzyme metabolized in the plasama (pseudocholinesterase)and tissue Excreted in urine Excreted in urine  Component (content) of L.A cartridge: 1 local anesthetic drug or agent Classification of local anesthetics 1- on the basis of chemical structure Ester and Amide 7 PHARMACOLOGY OF LOCAL 2- on the basis of duration of action ANESTHESIA (CLASSIFICATION) a - short –acting less than 30 minutes 8 as articaine , lidocaine , prilocaine b - long acting longer than 90 minutes 9 as bupivacaine. Intermediate acting:lasts about 60 minutes 3-- on the basis of occurrence in nature a - naturally occurring e.g. cocaine b - synthetic compound e.g. procaine , lidocaine.