Anesthesia is the introduction of substances in the body that are designed to cause temporary sensitivity suppression. The anesthetic is the substance with which it temporarily suppresses sensitivity. Examples of anesthetics: lidocaine, prilocaine, mepivacaine, hostacaine, articaine, bupivacaine, procaine, cocaine, tetracaine.
Dental anesthesia is indicated when the physician performs therapeutic acts that can be painful. The purpose of anesthesia is to make the treatment session to be as comfortable as possible and to reduce or eliminate patient’s anxiety and pain. Not all dental procedures are requiring anesthesia, but the most common are dental extractions, endodontic treatments and treatment of microbial tissue affections.
The principle of action of anesthesia
Local anesthetics act by stopping nerve conduction by reducing the flow of sodium ions in the cytoplasm of neurons. Sodium calling into neuron potassium ion is no longer able to go out, so it inhibits depolarization of nerve and anesthesia appears. The effect and duration of anesthesia depends on several factors: weight, body fat, the concentration of anesthetic, anesthetic gap between PH and the anesthesia.
The maximum dose of an anesthetic which can be administered is between 70 mg – 500 mg, also taking into account the patient’s age, state of health, the type of anesthetic and the presence or absence of vasoconstrictor. The maximum dose is not lethal dose, but has toxic effects on the body resulting in headache, hypotension, tremors, convulsions, incoherent speech.
Types of Anesthesia
1. Local anesthesia is done with local anesthetics and temporarily eliminates pain by acting only in a specific area of the oral cavity. This type of anesthesia is most commonly used in dental treatment in cases like: filling of deep carious lesions, teeth preparations for coverage with crowns, endodontic treatments or other surgical interventions.
In turn, local anesthesia is 2 types:
– Topical – anesthetics in the form of spray, pastes, gels, powders, liquids, ointments applied directly to mucosal tissue in order to prepare it for the injectable anesthesia or extraction of temporary teeth in children.
– By injection – local anesthetic solution is injected into the tissues that will surgically intervene or around them or injecting anesthetic at distance from the place of intervention. This can be intramucosally, intragingival, plexus (only one tooth anesthetized), truncal, intraligamentary, intrapapillary, intraseptal, intraosseous, intrapulpal.
2. Regional anesthesia numbs an area of the body, but the patient is conscious.
3. Sedation may be oral, gas or intravenous. Most often is used sedation in parallel with local anesthesia for a soothing intervention.
– For gas sedation it is used inhaled gas similar to that of general anesthesia, but in smaller doses so that after removing the mask of gas, the patient recovers in a few minutes without pain, help that was given by local anesthetic.
– Sedatives and oral fluids or the form of suppositories are administered to children during dental procedures to relax them.
– Deep sedation and general anesthesia are used for complex interventions when patients are unable to control their reactions. Patients will be in a state of depressed consciousness and they may feel the pain, so a local anesthetic is required
4. General anesthesia causes loss of sensation and lack of consciousness. It is rarely used in dentistry and is indicated in cases in which local anesthesia is not efficient or not cannot be achieved. The anesthetic is introduced intravenously or by inhalation of anesthetic gas, but it is necessary an endotracheal intubation too and monitoring the patient’s vital functions permanently.