 Hello everyone welcome back to another session in dentistry and more. So we are continuing our local anesthetic sessions So this session is about local anesthetic agent components So what are the components and its function in a local anesthetic agent? So we'll start straight away. So we have the basic local anesthetic agent can be xylokane or Lignokane the second one is vasoconstrictor Commonly used one is adrenaline which is in the dilution of 1 is to 80,000 and the third one is reducing agent which is there are product used is sodium meta by sulphate and Preservative is medial paraben then fungicide is thymine and vehicle Can be either distilled water or sodium chloride? So the first component is a basic local anesthetic agent The commonly used in dentistry xylokane and lignokane So it is 2 percentage. So it is a dilution factor. There's nothing but 2 gram in 100 ml So that is a weight by volume measurement So this is the component which produces local anesthesia The next thing is vasoconstrictor. So what is the role of vasoconstrictor? So From the name we get the idea. It is to constrict the vessels So commonly used is adrenaline or epinephrine It is to counteract the vaso-dialyteri action by Constricting the blade vessels. So what it does is it decreases the blood flow to the injection area and The absorption of the local anesthetic into the cardiovascular system is slowed which results in lower anesthetic level and thereby minimizing the risk of local anesthesia toxicity So it also increases the duration of anesthesia by Allowing the local anesthesia to remain around the nerve for a longer period of time So on a short it does three jobs. One is decrease the blood flow Decrease the blood flow to the injection area then decrease the toxicity because it slows the absorption into cardiovascular system and Also increases the duration so that it stays around the nerve for a longer period of time So what is the role of vasoconstrictor? We learned so what is the Overdossage result in so if we use more Vasoconstrictor more concentration of vasoconstrictor what happens is it will Taken up to the bloodstream which causes increase in the systolic and diastolic blood pressure at it increases the cardiac output and stroke volume So these actions lead to an overall decrease in cardiac efficiency. So always when we Do local anesthesia for a cardiac patient or someone with cardiac disease? We should always remove the adrenaline from the local anesthetic agent we give just plain local anesthesia to avoid the side effects of vasoconstrictor with respect to such patients and Regarding the dilution factor. So this is one is to 80,000 that means one gram per 80,000 milliliter. Oh, we can say point eight milli gram per ML that is the amount per unit volume. Okay, so that is a dilution factor. So that much diluted Quantity we are using in LA agent. That is a adrenaline or epinephrine So the next component is reducing agent or antioxidants The product is sodium metavisulfate. So this vasoconstrictor has one problem Because it is very unstable in solution and may oxidize especially on prolonged exposure to sunlight so once it is Oxidized the color will become brown and That is an indication that the solution must be discarded So we need to prevent that so in order to prevent that we add sodium metavisulfate as a reducing agent Okay So this reducing agent will compete for this available oxygen and the shelf life of the local anesthesia Or local anesthetic solution will increase. So reducing agent are compounds which Donates electron because it is very highly reactive Components so which donates electrons and become reduced and oxidizing agents which accept electrons and oxidized so Hope you all remember that red ox reaction the oxidation and reduction Reduction so reduction where it is donating electron oxidation where it is accepting electron So reducing agent we add this to increase the shelf life Okay, because this will compete for available oxygen. Oxygen is very bad for this vasoconstrictor Next we have preservative preservative is medial paraben or Caprile hydro cuprino toxin So modern LA solutions are very stable basically and often have a shelf life of two years or more so their sterility is maintained by the inclusion of small amount of preservatives such as medial Hydro cuprino toxin and Also, we have another one which is methyl paraben, but it has some disadvantages That is it is producing some allergic reaction for few people Next we have fungicide fungus in the past the some solutions It tended to become cloudy due to the proliferation of Minute fungus so in order to avoid that most of the solutions nowadays Add a little bit of thymol, which is a fungicide to prevent the occurrence of this fungal cloudy And vehicle which is distilled water or sodium chloride. So this anaesthetic agent and the additives refer to All the additives are dissolved in distilled water and sodium chloride. So this isotonic solution minimizes the discomfort during injection and There'll be also presence of sodium hydroxide to adjust the pH And the last component is nitrogen bubbles So there will be nitrogen bubbles within the cartridge It is to put To avoid the entrapment of oxygen. So if oxygen is there the problem is with vasoconstrictor So oxygen will destroy the vasoconstrictor that is adrenaline or epinephrine. So to avoid that There will be nitrogen bubble presence in the cartridge So these are the components of Local anaesthetic agent the basic component is xylokane or lignokine two percentage Then we have vasoconstrictor That is adrenaline and one is to 80,000 that is a dilution it decreases the blood flow to the site Decreases our systemic toxicity and increase the duration of action then the reducing agent which is anti-oxidant which is complete for the oxygen and Get reduced which is sodium meta by sulphate. Then we have preservative, methyl, paraben and capryl hydro Couponotoxin then fungicide thymol and all this will be added in the vehicle distilled water and sodium chloride We add sodium hydroxide to adjust pH and hydrogen bubble too Prevent the entrapment of oxygen. It's a very commonly asked Short essay or short not in oral surgery exam. So I'll come up with the next part of local anaesthesia Hope you understood this small concept. Thank you