WREB Study Guide with complete solutions.

WREB Study Guide with complete solutions.Local anesthesia depresses excitation in nerve endings or inhibiting the conduction of what nerves? periphreal LA differe from other drugs in that most other drugs are absorbed in the blood stream but LA stop their action once absorbed where? systemic circulation 00:03 01:17 Why are vasoconstrictors added to LA? decrease blood flow at injection site, constrict blood vessels and allows for a longer working time more profound anesthesia and less bleeding Why are additives and preservatives added to LA? prolong the shelf life by using antioxidant properties What are two examples of additives and preservatives? sodium bisulfite and sodium metasulfite Asthma patients are sensitive to what additive? sulfites If a person is allergic to sodium bisulfite do you use vasoconstrictor? No What does a yellow brown tint indicate? oxidation What should you do if there is oxidation in the carpule? dispose of it. Are LA's vasodilators or vasoconstrictors? vasodilators except cocaine its a vasoconstrictor What phase of nerve conduction has positive ca+ on the outside and negative on the inside with no movement of ions? resting state What phase of nerve conduction has increase permeability to NA+ ions becomes less negative within the nerve? deolarization slow phase What phase of nerve conduction has enough stimulous to make nerve fire with influx of sodium? rapid depolarization What phase of nerve conduction returns to resting state which Na goes out of the nerve and k returns in the nerve. influx of K+ Repolarization What is the site of action for a LA? nerve membrane LA are alkaloid bases meaning they are? wea combine with acids to form water soluble salts. Base form is lipophilic and non ionized or hydrohillic and ionized? lipophilic and non ionized. ph of normal tissue is 7.3 to 7.4 ph of local anesthesia is 5.5 ph of local anesthesia with epinephrine is 3.3 ph of inflamed tissue is 5.5 to 5.6 when there is an inflamed area it means less or more anesthesia is absorbed causing a slower or faster onset of action...meaning it reduces the potency of the drug and poor anesthesia. slower onset, less anesthesia Esters hydrolyzed to ______________in the blood by pseudocholinesterase. PABA Amides metabolized by the ___________ except prilocaine which is metabolized in the ___________ liver, lungs What should you avoid in patients who have liver failure? amides Where do amides and esters excrete? kidneys People who have kidney trouble renal disease have a hard time excreting which LA? mepivicaine. Which LA do we want to avoid if a patient is allergic to a sulfa? articaine What happens if a patient is allergic what happens to them? rash or anaphylaxis Do amides cause allergic reactions? No Vasoconstrictors have an alpha or beta effect on vasoconstrictor causing constriction of blood vessels? alpha Vasoconstrictors exert their action directly on the what receptors? adrenergic An overdose amount of vasoconstrictor would produce what effect alpha or beta? Beta affect heart and smooth muscle reactions, vasodilation and bronchodilation Persistent anesthesia or altered sensation well beyond the expected duration is called paresthesia how do you give a patient facial paralysis deposit anesthesia near the facial (cranial 7) nerve in capsule of paratid gland prolonged spasm of the muscles of mastication is called trismus Trismus happens most offten with what injections? psa and ianb What is the treatment for trismus heat therapy for twenty min every hour or anti inflammatory analgesic diazepam 10mg how can you give a patient a hematoma nicking an artery when is a hematoma most likely to occur what injection? psa, ia, mental, io outside of face is psa can you get a hematoma on the palate? no how do you treat hematoma? ice for 2 min with reasure burning on injection what is the cause ph of la solution more acidic, rapid injection, contamination of LA, la too hot if you are allergic to one ester are you allergic to all? yes What is common preservative in fruit and vegies? sodium bisulfite If a person has a allergic reaction to a sodium bisulfate is it the LA or the Vaso? Vaso Can you have an allergy to epinephrine? no What is the most dramatic and acutely life threatening allergic reaction? Anaphylaxis If a patient has a non lifethreatning reaction what do you do benedryl/diphenydramine 50mg for 4 days if the patient has a life threatning anaphylaxis immediate reaction what do you do activate ems, administer oxygen, epi 0.3 mg every 15 min, 50 mg diphenhydramine what is an increased tolerance to a drug that is administered repeadatly trachyphlaxis What initiates nerve conduction dendric zone what is not involved in impulse transmission? cell body What are terminal branches that distribute incoming signals to various CNS nuclei responsible for processing axon what is term for the ability of the impulse to jump quickly from one node to the next? salutatory conduction What are the smallest nerve fibers cfibers what are the largest fibers the most rapid conducting axons and transmite sharp dental pain a fibers what fibers are not involved in transmitting dental pain b fibers what fibers cause dull or burning pain c fibers Afferent or sensory nerves conduct impulses to the CNS Efferent or motor neurons conduct messages from the CNS to the periphery of the body What starts the afferent nerve conduction? dendric zone What is a long nerve fiber that runs the whole length of the nerve? axon What is the axon incased nerve membrane called axolemmas and are surrounded by myelin sheath What is the gelatinous substance inside the axon membrane called axoplasm What is the theory that postulates that the local anesthetic interferes with the sodium channel and blocks the sodium transfer necessary for nerve conduction? specific receptor theory The anesthetic must permeate how many mm of the nerves length to profoundly block the generation of nerve impulse. 8-10mm If an injection is done two times and still does not produce pain control why is that? because of a lower ph of the tissues, edema, hemmorrhage or transudation of surrounding areas. Why is anesthesia not as effective when there is an infection? ph of the tissue is too low to allow anesthetic to penetrate the nerve What is the largest fiber A fiber The smallest fiber C fiber Which fiber does not have a myeline sheath c fibers. What fibers are most easily blocked by local anesthesia c fibers. because no myelin sheath makes it easier to access the nerve. What can happpen with toxic blood levels? anesthesia depress the CNS and cause patient to have convulsions. Ester anesthetics are metabolized in the blood stream by pseudocholinesterase Esters are contraindicated in patients who report they have atypical pseudocholinesterase production Where are amides metabolized liver Why are vasoconstrictors added to local anesthetics? decrease the absorption of the drug, prolong the anesthetic effect reduce risk of toxisity What are the most commonly used vasoconstrictors used in dentistry? epinephrine and levonordefrin Epinephrine is good for hemostatis What is the recommended topical form of lidocaine? 200mg What is the most commonly chosen anesthetic today lidocaine with 1:100,000 ei. Why is 3% mepivicaine without vasoconstrictor used patients who cannot take a vasoconstrictor or for short procedures. What do you use if you want pulpal anesthesia for longer apointments or when post operative pain is anticipated? Bupivicaine Why is Bupivicaine not recommended to children or handicapped patients? increased risk of postoperative injury (chewing on a numb lip) Why would there be mild burning sensation during administration of anesthesia? ph of solution, too warm, contamination. Does an artery or vein cause hematoma? artery What is treatment for trismus? Heat therapy 20 minutes every hour. and analgesic and muscle relaxants if necessary.