which has thicker cortical plate, maxillary or mandibular? CORRECT ANSWER mandibular (this decreased the amount of the local anesthesia molecules that can
... [Show More] penetrate to nerves during infiltration injections)
due to the thickness of cortical bone, which is a good option for local anesthetic in the mandibular arch during infiltrations? CORRECT ANSWER Articaine (Septocaine) is sometimes effective for mand. infiltrations (4% vs. 2% for lidocaine) due to the increased number of molecules
hematomas are most common with which type of injection, and why? CORRECT ANSWER PSA due to nicking a vessel in the pterygoid plexus of veins
what is the TX for a hematoma? CORRECT ANSWER pressure, cold compresses on/off, NSAIDS, and time.
a positive aspiration when administering a PSA is due to what? CORRECT ANSWER aspirating hemorrhage caused by injection
what are the three most common locations for hematomas to occur? CORRECT ANSWER 1. PSA
2. IA
3. mental
blanching of the tissue following/during an injection is caused by what? CORRECT ANSWER vasospasm/vasoconstriction caused by epinephrine or brushing against autonomic nerves stimulation vasospasm
the pterygomandibular space/triangle is bordered by what anatomical structures? CORRECT ANSWER ramus, lateral pterygoid muscle, and medial pterygoid muscle
the pterygomandibular space/triangle is identified intra-orally by what? CORRECT ANSWER pterygoid hamulus (palpation), coronoid notch (palpation), and pterygomandibular raphe (visual)
the mandibular foramen lies approx. __________________________ of the distance from the anterior border of the ramus to the posterior border CORRECT ANSWER 1/2 to 2/3
Antero-posteriorly, the greater palatine foramen is located between the ___________________________. CORRECT ANSWER middle of the maxillary second molar and the middle of the third molar in about 80-90% of patients.
all arteries leading to the oral cavity receive blood from what? CORRECT ANSWER external carotid (most are direct or indirect branches from the maxillary artery with the exception of the lingula -- this is a direct branch from the external carotid)
veins from the oral cavity will drain into what? CORRECT ANSWER internal jugular (both internal and external drain into the brachiocephalic veins which drain to the superior vena cava
do myelinated or un-myelinated nerves create faster impulse? CORRECT ANSWER myelinated (impulses jump from node to node -- node of ranvier)
what is saltatory conduction? CORRECT ANSWER the process of nerve impulses jumping from nodes of ranvier along a myelinated nerve
what is the resting potential charges of a nerve? CORRECT ANSWER inside is negative and outside is positive
what molecules are predominately outside/inside at resting potential? CORRECT ANSWER Na+ outside and K+ inside
what is depolarization? CORRECT ANSWER Na+ channels open, Na+ flows in reversing polarity; K+ flows out to restore neutrality; the Na+ and K+ pumps restore polarity (resting potential)
what is the mechanism of action for local anesthetics? CORRECT ANSWER blocks the Na+ channels preventing depolarization
what is the basic structure of anesthetics? CORRECT ANSWER aromatic ring (lipid soluble), intermediate chain (amide or ester configuration), and terminal amine (able to ionize and become water soluble)
lipophilic vs. hydrophyllic CORRECT ANSWER lipophilic is lipid soluble and hydrophyllic is water soluble
what makes the terminal amine so important to the structure of local anesthetic? CORRECT ANSWER this allows the local anesthetic to the both lipid soluble and water soluble at the appropriate times (ex: hydrophyllic for dilution and pH control; lipophyllic in order to penetrate neuron cell membrane; hydrophyllic to block Na+ channels)
what is pKa and what does it do? CORRECT ANSWER the dissociation constant - this identifies the pH at which the anesthetic exists in a 50/50 ratio of the ionized to non-ionized (hydrophyllic to lipophyllic) molecules
lipid solubility of local anesthetics CORRECT ANSWER the different structure of the various anesthetics confers varying degrees of lipid solubility (the greater the lipid solubility of the basic molecule the more potent it is)
protein binding of local anesthetics CORRECT ANSWER the greater degree of protein binding, the more molecules you have waiting in reserve for later action (the more proteins bound, the longer the duration)
vasodilation and the local anesthetics CORRECT ANSWER with the exception of cocaine, all anesthetics are vasodilators (undesirable as this promotes quicker vascular uptake/metabolism and therefore less anesthetic action)
what is biotransformation? CORRECT ANSWER metabolism
where are amides metabolized and where are esters metabolized? CORRECT ANSWER amides: liver (in order to be rendered water soluble so that they can be excreted in the kidneys)
esters: plasma by cholinesterase (more rapid than hepatic leading to shorter duration)
what is the only amide anesthetic that also contains an ester group, and how is it metabolized? CORRECT ANSWER Articaine (septocaine) this agent is metabolized both hepatically and by plasma cholinesterase
ester onset and duration CORRECT ANSWER slow onset with short duration
amide onset and duration CORRECT ANSWER fast onset and longer duration
are esters or amides more likely for toxicity? CORRECT ANSWER esters are more likely to cause toxicity
what does NaCl do to the anesthetic solutions? CORRECT ANSWER makes the solution isotonic
what does HCL do to the anesthetic solutions? CORRECT ANSWER lower the pH for the addition of epinephrine
what does epinephrine do the anesthetic solutions? CORRECT ANSWER reduce absorption rates at site of injection (increase duration/reduce blood levels - toxicity)
what do bisulfites do to the anesthetic solutions? CORRECT ANSWER reduce the oxidation of the epinephrine (longer shelf-life)
what does methylparaben do to the anesthetic solutions? CORRECT ANSWER agent used for its antibacterial action that is no longer contained in dental cartridges, only in multiple dose vials
what are all of the effects that result when epinephrine is added to a solution? CORRECT ANSWER increased heart rate, increased systolic pressure, lowers diastolic pressure
what is the MCD (maximum cardiac dose) of epinephrine? CORRECT ANSWER 0.04 mg (40ug)
what are the available options for lidocaine? CORRECT ANSWER 2% either with 1:100,000 or 1: 50,000 epi
what are the available options for mepivacaine? CORRECT ANSWER 3% plain or 2% with 1:20,000 levonordefrin
what are the available options for prilocaine? CORRECT ANSWER 4% plain and 4% with 1:200,000 epi
what are the available options for articaine? CORRECT ANSWER 4% with 1:100,000 epi only
what are the available options for bupivacaine? CORRECT ANSWER 0.5% with 1: 200,000 epi only
what is the shortest acting anesthetic and what is the longest acting anesthetic? CORRECT ANSWER shortest: mepivacaine
longest: bupivacaine [Show Less]