Local Anesthetic Chaper 1-4
Which local anesthetic would be appropriate for a patient with a history of true bisulfite allergy?
4% prilocaine
Which nerve fiber type is responsible for pain related to temperature?
A delta
Patients who are overly tired or stressed at the time of their dental appointment will generally demonstrate what kind of pain reaction threshold?
A lower pain reaction threshold, which means that they have a low tolerance for pain
Patients who frequently miss dental appointments because of apprehension often demonstrate what kind of pain reaction threshold?
A lower pain reaction threshold, which means that they have a low tolerance for pain
What is the most distal arborization of the nerve endings called?
Dendritic zone
What does the specific protein receptor theory of the action of local anesthetics suggest?
Displaced Ca++ and local anesthetic drugs compete to bind to receptor sites within the ion channels of cell membranes.
What are the nerves that conduct signals away from the brain or spinal cord called?
Efferent nerves
What is the layer of connective tissue that surrounds each axon within a nerve called?
Endoneurium
Which drug, added to dental local anesthetics, is helpful for achieving hemostasis?
Epinephrine
What is the layer of connective tissue that surrounds the entire nerve called?
Epineurium
If more anesthetic is needed for a procedure, it is important to reinject the anesthetic after the mantel fibers have fully recovered.
False
Levarterenol is no longer available in the United States
False
Local anesthetics affect the CNS and CVS after biotransformation
False
Local anesthetics are vasoconstrictors and decrease the absorption of the drug by the blood
False
Prilocaine is biotransformed in the liver only
False
The higher the pKa of an anesthetic, the faster the onset of action
False
Which of the following is true regarding the nodes of Ranvier?
Found along myelinated nerve fibers between adjacent Schwann cells
What is another name for the elimination of the local anesthetic from the blood and tissues?
Half-life
Who was the first dentist to use "laughing gas" for dental procedures?
Horace Wells
Which component of the local anesthetic molecule renders the molecule water soluble?
Hydrophilic amino group
The difference between the legal wording that states that the dental hygienist may monitornitrous oxide and that the dental hygienist may administer nitrous oxide is best explained by which of the following statements?
In legal terms, someone with the authority to monitor nitrous oxide may change the nitrous oxide and/or oxygen settings; someone with the authority to administer nitrous oxide may turn on the apparatus.
Why is protein binding an important characteristic of local anesthetic drugs?
Increased protein binding allows more cations (RNH+) to bind to the receptor sites within the sodium channels, prolonging the presence of anesthetic at the site of action.
The time interval between the initial deposition of the anesthetic solution at the nerve site and complete conduction blockade is referred to as the:
Induction time
Which part of the chemical structure of a local anesthetic determines the pattern of biotransformation of the anesthetic
Intermediate chain
Jon presents to your dental office in pain with an abscessed tooth. Utilizing the Visual Analog Scale (VAS), Jon indicates that his pain level measures about 95 mm in length from the left hand end of the horizontal line. What is an appropriate translation of this action?
Jon is experiencing a significant amount of pain.
The most popular dental local anesthetic used in the United States today is which of the following?
Lidocaine
Which component of the local anesthetic molecule improves the lipid solubility, facilitating the penetration of the anesthetic through the lipid-rich membrane where the receptor sites are located?
Lipophilic aromatic ring
The creation of the loss of sensation in a circumscribed area, without loss of consciousness, best defines which of the following?
Local Anesthesia
The difference between the electrical charge on the outside of the cell and that on the inside of the cell is called what?
Membrane potential
The cell body of which neuron participates in impulse conduction and therefore is located at the terminal arborization?
Motor neurons
What are the endogenous chemicals that transmit signals from a neuron to a target cell across a synapse called?
Neurotransmitters
An unpleasant sensory and emotional experience is called what?
Pain
The neurologic experience of pain is referred to as what?
Pain perception
The personal interpretation and response to the pain message is called what?
Pain reaction
Lidocaine is said to have revolutionized pain control in dentistry. Why?
Patients experience fewer allergic reactions with lidocaine
What is the significant clinical difference between esters and amides?
Potential for allergic reactions
The use of anesthesia as needed is an important key to what?
Preventing fear associated with pain
The best method to manage an anxious patient is by:
Prevention
The nerve cell stage in which potassium returns to the inside of the cell and sodium returns to the outside of the cell is called what?
Refractory period
What is the propagation of action potentials along myelinated axons from one node of Ranvier to another called?
Saltatory conduction
As the action potential moves down the line, its strength decreases as it moves from one neuron to the next. The action potential in myelinated axons does not propagate as waves as in unmyelinated axons.
The first statement is false; the second statement is true
The function of the cell body is to transmit impulses. The cell body is responsible for protein synthesis and provides metabolic support for the neuron.
The first statement is false; the second statement is true.
Performing a complete health history review at every appointment helps practitioners recognize stressors and health conditions that may complicate dental procedures. Taking a patient's vital signs does not play an important role in assessing a patient's level of apprehension.
The first statement is true; the second statement is false
The liver is the organ responsible for the entire metabolic process of most amides. The rate of biotransformation is faster in patients with significant liver dysfunction.
The first statement is true; the second statement is false
Pain threshold is best described as which of the following?
The point at which a sensation starts to be painful and discomfort results
What factor/factors determine the severity of an overdose reaction to local anesthetic?
Time lapse between the administering of the local anesthetic to the overdose
Which of the following is a major route of delivery of local anesthetic drugs?
Topical
Local anesthetics easily cross the blood-brain barrier
True
The most potent local anesthetic is bupivacaine, which has the greatest degree of lipid solubility
True
The rate of systemic absorption of local anesthetics depends on the total dose, concentration, route of administration, vascularity of tissues, and presence or absence of a vasoconstrictor
True
The speed of recovery from local anesthetic is determined by the degree of binding to the receptor site of each anesthetic
True
ntravascular injections significantly increase the possibility of an overdose
True
In 1842, who was known for assisting a dentist by administering ether to a patient?
William Clarke
Which is the primary factor that determines the onset of action?
pKa of the anesthetic agent
What are the nerves that conduct signals from sensory neurons to the spinal cord or brain called?
Afferent nerves
Why is lipid solubility an important characteristic of local anesthetic drugs?
All options listed: A greater lipid solubility enhances the diffusion of the anesthetic drug through the nerve, A greater lipid solubility indicates a higher potency of the anesthetic drug, A greater lipid solubility allows for a lower effective dose of the local anesthetic drug
Considerations that have the potential of influencing a dental patient's pain reaction threshold include which of the following?
All options listed: Age, Culture, Fatigue
Tachyphylaxis is a term used to describe what phenomenon?
All options listed: An increased tolerance to a drug that is administered repeatedly, If the dental procedure lasts longer than the duration of the anesthetic and the mantel and core fibers have fully recovered, the reinjection of local anesthetic will be ineffective, Once the mantel fibers return to function, the patient experiences pain, yet administration of anesthetic does not alleviate the pain.
Local anesthetic agents used in dentistry:
All options listed: Cause loss of nociception, Prevent generation of a nerve impulse, Prevent conduction of a nerve impulse
What is another name for axons?
All options listed: Core bundles, Mantle bundles, Nerve fibers
What factor/factors influence(s) the duration of the effects of local anesthetics?
All options listed: Degree of protein binding, Vascularity of injection site, Addition or absence of a vasoconstrictor
Dissociation constant refers to which of the following descriptions?
All options listed: Determines the portion of administered anesthetic dose in the lipid-soluble state (RN), Determines the onset of anesthetic action as the increase of molecules crossing the nerve membrane decreases the time of the anesthetic's onset, The pH at which 50% of the molecules exist in the lipid-soluble form and 50% in the water-soluble form
The benefit of local anesthesia is not limited to pain control but could also include which of the following?
All options listed: Hemostasis, Time management, Patient-centered stress reduction
Procaine was used extensively in dentistry for a number of years; however, it was not the ideal local anesthetic. Why not?
All options listed: It took a long time to produce the desired anesthetic result, It wore off quickly, It had a high potential for triggering allergic reactions
The first objections to the use of inhalation sedation included which of the following?
All options listed: It was viewed as a religious offense, It was viewed as an unethical practice, It was viewed as a retardant to the health process
The axon is:
All options listed: Made up of cytoplasm, Surrounded by a multiple lipid membrane
An astute practitioner looks for signs of patient anxiousness. These signs may include which of the following?
All options listed: Overwillingness to cooperate with clinician, History of emergency dental care only, Elevated blood pressure and heart rate
The relationship between relative amounts of ions inside and outside the nerve membrane is known as which of the following?
Concentration gradient
Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order "to get everything done at one time." A review of Sam's health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that it has actually gone down since the beginning of the appointment. What thoughts should be going through your mind at this time?Why do you think Sam's blood pressure decreased from the beginning of the appointment?
All options listed: Sam became more comfortable during the appointment, Symptoms of a CNS and CVS overdose are biphasic, Symptoms of a possible overdose change from a stimulation phase to a depression phase
Considering the human needs paradigm, freedom from fear and stress includes which of the following?
All options listed: The need to receive appreciation, attention, and respect from others The need to be free from emotional discomfort The need to feel safe
Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order "to get everything done at one time." A review of Sam's health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that it has actually gone down since the beginning of the appointment. What thoughts should be going through your mind at this time?Reflecting on your experience with Sam, what other factors may contribute to an incident similar to Sam's?
All options listed: The use of topical anesthetics plus intravascular injections, An injection that is administered too rapidly, The perio infection and inflammation
Dental anxiety may be attributed to which of the following?
All options listed: Unpleasant dental experiences in the past, Learned dental fear from a parent
Early methods of pain control included which of the following?
All options listed: Use of opium, Scaring off of demons, Roots, berries, and seeds
Which description best describes the mechanism by which local anesthetic drugs work?
Anesthetic drugs bind to the sodium channels, the influx of sodium is interrupted, the action potential cannot rise, and the signal conduction is inhibited.
What does the membrane expansion theory of the action of local anesthetics suggest?
Anesthetics that are highly lipid soluble cause the lipoprotein matrix of the nerve membrane to expand, narrowing the sodium channels, thus preventing depolarization
The newest amide to arrive on the dental market in the United States is which one of the following?
Articaine
Which anesthetic drug has a short half-life of 45 minutes and is the least toxic of the anesthetics?
Articaine
Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order "to get everything done at one time." A review of Sam's health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that it has actually gone down since the beginning of the appointment. What thoughts should be going through your mind at this time?Considering Sam's health history, what anesthetic drug may have been a better choice?
Articaine with epinephrine
A highly effective analgesic and antipyretic compound, introduced in 1899 and still used today, is commonly referred to as what?
Aspirin
What is the inability to hydrolyze ester local anesthetics and other chemically related drugs called?
Atypical pseudocholinesterase
What is the name of the portion of the sensory neuron that is easily excited and has the most negative action potential threshold?
Axon hillock
Anesthetic recovery is a slower process than induction because the anesthetic binds to the receptor site in the sodium channel, releasing the anesthetic slowly into the systemic circulation.
Both the statement and the reason are correct and related
Which receptors have inhibitory actions from adrenergic drugs on smooth muscle?
Beta receptors
The A alpha nerve fiber type is the smallest and the most numerous nerve fiber. The A delta nerve fiber type is primarily responsible for dull, aching pain.
Both statements are false
After absorption of the local anesthetics into the bloodstream, they are distributed throughout the body to all tissues. Highly vascular organs such as the brain, heart, liver, kidneys, and lungs have higher concentrations of anesthetics
Both statements are true
Ester local anesthetics have a high probability of producing an allergic reaction compared to amide local anesthetics. A patient who has an allergic reaction to one ester agent is likely to experience hypersensitivity to all ester anesthetics
Both statements are true
Opium was used as an early method for pain reduction. Later, when converted to morphine, it became even more effective when injected into the bloodstream.
Both statements are true
Tasks for neurons include receiving, processing, and sending information. They communicate with other neurons through axons and synapses.
Both statements are true
The absorption of epinephrine is retarded because of the drug's vasoconstricting properties. It may take several hours for absorption to be completed
Both statements are true
The lipoprotein sheath that surrounds many neurons is called the myelin sheath. The myelin sheath is composed of Schwann cells.
Both statements are true
The smaller-diameter nerve fibers associated with supraperiosteal injections are more sensitive to local anesthetics. The larger-diameter nerve fibers of the IA and PSA require a larger volume of local anesthetic for successful nerve blockage.
Both statements are true
Esters, benzocaine, tetracaine, and procaine are hydrolyzed in the plasma by the enzyme pseudocholinesterase and by liver esterases. Procaine is metabolized to PABA and is the major metabolic by-product responsible for allergic reactions
Both statements are true.
Adding vasoconstrictor to local anesthetics can result in reduced systemic toxicity and increased duration of anesthetic because the vasoconstrictor reduces the rate of absorption
Both the statement and reason are correct and related
The main difference between motor neurons and sensory neurons is the location of which body part?
Cell body
The first local anesthetic used in dentistry was which of the following?
Cocaine
Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order "to get everything done at one time." A review of Sam's health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that it has actually gone down since the beginning of the appointment. What thoughts should be going through your mind at this time?Based on Sam's physical symptoms, what should you consider?
Sam may be experiencing a cardiovascular crisis
What do local anesthetic drugs inhibit in order to prevent nerve cell stimulation?
Sodium influx
The physical and emotional response to a specific situation is referred to as which of the following?
Stress
At the synaptic knobs of neuron cells, what type of action is required to have the electrical impulse cross the synapse of one cell to another cell?
The action of either electrical or chemical synapses
What characteristic of local anesthetic drugs determines the speed of nerve recovery?
The degree of protein binding
