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Local Anesthetics Dental hygiene II Midterm

Terms in this set (35)

Know where Prilocaine is biotransformed (broken down)
Liver
Kidneys
Lungs
Know the two types of adrenergic receptors and which one predominates.
Alpha
Beta
Beta actions predominate.
List which organs are primarily affected by Beta 1 and Beta 2 receptors.
Beta 1: primarily affect the heart.
Beta 2: primarily affect the lungs.
Know the single most important improvement in dental local anesthetics syringes.
The addition of the aspirating harpoon for safety reasons.
'Traveling down an axon in one direction toward the synapse' would be a description of:
An action potential in a neuron
Know what kind of action is required to have electrical impulse cross the synapse of one cell to another cell.
The action of either electrical or chemical synapses.
Name some responses that a body could have to fear:
Increased blood pressure
Muscular tension
Anxiety
Irritability
Hyperventilation
What are the active ingredients used in Oraqix? Can they be used in injectables.
2.5% Lidocaine and 2.5% Prilocaine gel mixture.
Gel mixtures are not used in injectables.
Whats the importance of the pKa number.
The pKa number is the primary factor that determines the onset of action. The lower the pKa number the faster or shorter the time it takes to start numbing. And vice-versa. The higher the pKa number the slower or longer the time it takes to start numbing. There is a chart in the textbook.
The closer the pKa number of the anesthetic i.e., 7.7, is to the pH of the tissue of the body i.e.,7.4, the more profound the numbing action will be.
Compare the pain associated with a lower pH and a higher pH.
--The lower pH (acidic) of inflamed tissues will produce a more uncomfortable injection with a slower onset of action.
--The higher pH (more alkaline) of healthy tissues will produce a more comfortable injection with a faster onset of action.
Which local anesthetic molecule improves the lipid solubility which allows penetration of the nerve membrane.
The Hydrophilic amino group
Know the name of the layer of connective tissue that surrounds each axon within a nerve cell.
Endoneurium
Know which local anesthetic is the most potent and has the greatest degree of lipid solubility.
Bupivacaine
What are the factors that influence the duration of the effects of local anesthetics.
Vascularity of the injection site
Addition or absence of a vasoconstrictor
Degree of protein binding
Name the nerve cell stage in which the nerve cell is at rest at -70mv.
Polarization
The primary effects of local anesthetics occur during what phase.
Depolarization phase
In a resting neuron, what positive ion is most abundant outside the plasma (nerve) membrane?
Sodium (Na+)
List other names for an axon.
Core bundles- fasciculi located near the center of the nerve.
Mantle bundles- fasciculi located near the outside rim of the nerve.
20% Benzocaine topical is more concentrated than 5% Lidocaine topical plus all of the amide injectables of 2%, 3, & 4%.
T/F
True
20% Benzocaine is an ester. It is available in a cream, gel/ointment, spray and patch. T/F
True
How much time 4% Articaine with 1:200,000 epinephrine provides for pulpal anesthesia.
60-75 minutes
State which anesthetic would be chosen for a patient with a sensitivity to Epinephrine and a need for 30 minutes of pulpal anesthesia.
3% Mepivacaine plain
List some clinical observations of Methemoglobinemia.
-A bluish skin tone, nail beds and lips.
-Patient needs Methylene Blue I.V. which can reverse the condition in 15 minutes.
-Can be hereditary.
-Condition from breakdown of Prilocaine
Rule of thumb: The larger the gauge number, the smaller the lumen (opening).
The smaller the gauge number, the larger the lumen (opening).
T/F
True
Hyper-responder: persons who over-respond to LA. They stay numb for a longer amount of time than expected.
T/F
True
List the different solutions available for Mepivacaine.
3% Mepivacaine plain or (HCL)
2% Mepivacaine w/levonordefrin 1:20,000
Know how many minutes of pulpal anesthesia one gets from 2% Lidocaine w/epi 1:100,000.
60 minutes
Know which part of its chemical structure determines if a local anesthetic will be an ester or amide.
The intermediate carbon chain
Describe what happens to the local blood vessels in the area of injection immediately after a plain local injection.
Vasodilation of the blood vessels and increased blood flow to the site of injection.
Name the two local anesthetics with the least vasodilatory properties:
Mepivacaine (plain)
Prilocaine (plain)
Define relative and absolute Contraindications
-Relative Contraindication: Local anesthetic may be administered, but only after careful weighing of the risk versus the benefit to be gained.
-Absolute Contraindication: Local anesthetic must NOT be administered under any circumstance.
Know about Benzocaine:
-We use 20% Benzocaine gel/ointment as the preferred topical.
-It is an ester but is not water soluble so most of it stays in one place on the tissue to numb. Because of this we do not have to worry about much of it entering our system and causing an allergic reaction by turning into PABA.
-Also because of the above the tissue gets the full numbing power of the topical.
-The onset of action is rapid.
-The duration of action is 5 to 15 minutes.
-It is much more concentrated at 20% than injectable amides which are at 2%, 3%, and 4%.
-Adverse reactions are associated with tissue discoloration, sloughing, or burning/stinging.
-Can allow for a pain-free injection, and a pain-free application.
Name the solution that used to be added to the cartridge of local anesthetic to prevent bacterial growth.
Methylparaben
Describe 'negative pressure', negative aspiration, and 'positive aspiration'.
-Negative pressure is produced when the thumb ring of a syringe is pulled back by the clinician, causing retraction of the rubber stopper.
-Negative Aspiration is produced when there is a clear air bubble entering the cartridge, or no return, after negative pressure is applied to the cartridge.
-Positive aspiration is when blood is drawn into the cartridge during an aspiration from accidentally being in a blood vessel.
Know the maximum recommended dosage of epinephrine per appointment for the patient's below:
-Healthy patient: 0.2 mg of epinephrine per appointment
-Medically compromised patient: 0.04 mg of epinephrine per appointment (or a cardiac dose of 2 cartridges)
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