Flashcards in Midterm Deck (83):
T/F: The sodium channel has two gates, one for activation, and one for inactivation.
Initial depolarization widens the channel, opening the activation gate
Inactivation gate closes and allows the channel to reset - refractory period
What is the local anesthetic mode of action?
Block the influence of stimulation (depolarization) on Na+ permeability
What is the specific receptor theory of nerve blockade?
Anesthetic agent accesses and blocks channel from the intracellular side
Charged agents only block stimulated nerves
What is a phasic block?
Means only stimulated nerves are blocked
What are the three parts to the chemical structure of local anesthetic?
1. Aromatic group (hydrophobic)
2. Intermediate chain (amide or ester)
3. Amino group (hydrophilic)
The aqueous distribution constant (Q) reflects the ability to penetrate hydrophobic tissue and correlates with the _________ of the LA.
The dissociation constant (pKa) is the proportion of ionized to un-ionized molecules and correlates with the ___________ of the LA.
In what order do are sensations affected by LA?
1. dull pain
4. sharp pain
What is the normal pH of anesthetics?
T/F: Most anesthetic compounds come with a vasoconstrictor.
T/F: All local anesthetics are vasodilators.
This is why vasoconstrictors (epinephrine) are in the carps
T/F: Anesthetic that is bound to protein will have the strongest effect.
What are some conditions that will increase and decrease binding of LA to proteins?
Increase: MI, cancer, trauma, surgery, chronic pain
Decrease: Pregnancy, oral contraceptives, estrogen supplementation, acidosis, increasing dose
Unbound LA will distribute to the ______ first.
How long will it take unbound LA to distribute to the muscle?
__________ anesthetics are broken down by circulating plasma pseudocholinesterase.
___________ anesthetics are broken down by hepatic metabolism.
What will be the systemic vascular effects at moderate concentration of LA?
Decreased HR, cardiac output, PVR
The more ____________ an anesthetic is, the greater the risk for cardiac toxicity.
What processes decrease under sympathetic stimulation?
Disestive and secretory actions
Alpha receptors stimulate __________ or smooth muscle in blood vessels.
_________ receptors are found in the heart and produce cardiac stimulation.
What will happen under activation of alpha-1, beta-1, and beta-2 receptors?
Alpha-1: increase blood pressure
Beta-1: Increase heart rate
Beta-2: Decrease blood pressure
Why is antioxidant found in the LA carp?
To protect the vasoconstrictor
Why is HCl or NaOH found in some carpules?
pH adjusting agent
What are the 4 major reasons for adding vasoconstrictor to the carp?
2. Slow CV absorption -> lower toxicity risk
3. Stays where its put -> longer duration
What are the three types of sympathomimetic drugs (vasoconstrictors)?
1. Direct acting - directly on receptors
2. Indirect acting - use NE release
T/F: Epinephrine is a direct acting sympathomimetic drug.
T/F: A 1:50,000 concentration of vasoconstrictor is more potent than a 1:100,000 concentration.
What is the volume of a carp?
What is the maximum epinephrine dose for an ASA I patient per appointment? Patient with heart disease?
0.2 mg; 0.04 mg
T/F: The beta effects of epinephrine predominate.
Which antioxidant is added with epinephrine?
How many cartridges of 1:100,000 epinephrine can a patient with CV disease receive per appointment?
2 carps, 0.04 mg epi
If a patient is taking non-selective beta blockers what will be the effect of the VC?
Hypertension and bradycardia
Because cardiac changes will be blocked and alpha receptors will dominate
What could be an effect of VC taken with TCAs?
They will block reuptake of E and NE so effects will be exaggerated
What are the contraindications for using vasoconstrictors?
1. Severe CV disease (ASA IV)
2. Acute MI
3. Unstable angina
4. Cardiac dysrhythmias
5. Uncontrolled hyperthyroidism
What are some ways to deal with high stress patients?
1. Morning appt
2. Short wait
3. Nitrous oxide
4. Excellent LA
5. Short appt
T/F: Patients with a stable angina should be treated in a monitored setting.
Stable - be cautious with stress/epinephrine
Unstable - treat in monitored setting
How should a patient with controlled hypertension be treated?
Pressure should be monitored, should recheck 5 minutes after initial check
What are some ways to recognize uncontrolled hyperthyroidism?
Thin, heat intolerant, hyperdynamic, proptotic
When should dialysis patients be treated for dental problems?
The day after dialysis
T/F: Epinephrine should be avoided in cocaine abuse patients.
T/F: Patients taking tricyclic antidepressants or MAO inhibitors should have their BP monitored during treatment.
What are the four criteria for a syringe?
1. Provide aspiration
2. Durable, sterilizable
3. Inexpensive, light, simple
4. Wide variety of carps and needles
T/F: The higher the gauge, the thicker the needle.
Lower gauge = thicker
T/F: Cartilages should be stored in antiseptic to keep them clean.
Semi-permeable membrane - carps will get contaminated
T/F: Carps should be stored in a refrigerator.
T/F: Both hands should be used to recap the needle after LA has been administered.
One handed "scoop" technique
What structures are innervated by the inferior alveolar nerve?
1. Mandibular teeth to the midline
2. Body of mandible
3. Buccal mucoperiosteum anterior to 1st molars
What structures are innervated by the long buccal nerve?
Buccal mucoperiosteum of mandibular molars
What structures are innervated by the lingual nerve?
1. Anterior 2/3rds of tongue and floor of mouth
2. Lingual mucoperiosteum
Where in the mouth is infiltration very difficult?
Posterior mandibular teeth
Where is the point of insertion when administering LA via infiltration?
Point of intersection between the long axis of the tooth and the mucobuccal fold
The point of entry for an IA block is _________ to the coronoid notch and ___________ to the pterygomandibular raphe.
T/F: Bone should be contacted when giving an IA block.
Where should the barrel of the needle be resting when giving an IA block?
On the premolars opposite the side of injection
How much of the dental needle should be in the tissue during an IA block?
2/3 - 3/4 the length of the long needle
T/F: The needle tip will be slightly superior to the mandibular foramen during an IA block.
During an IA block, the needle penetrates the _________ muscle and enters the ______________ space.
If you touch bone too early how should you shift your angulation?
Switch so you are coming from canine region
How do you block the lingual nerve?
After IA block, slightly withdraw the needle and inject
If you are working on a lateral incisor and the patient still feels pain after an IA block, what is the likely problem?
Cross innervation from contralateral IAN - do slight infiltration
Where is the point of insertion for a LB nerve block?
Mucous membrane distal and buccal to most distal molar tooth
What will be numb with a mental nerve block?
Both incisor teeth and buccal mucosa
What is the Gow-Gates technique?
A way to get a true complete mandibular block
Aiming for the lateral side of the condylar neck
Have patient open wide, insert needle just distal to maxillary 2nd molar from opposite corner of the mouth, touch bone, aspirate, deposit
What is the advantage of the Vazirani-Akinosi technique?
Closed mouth technique
What is a concern for patients with bleeding disorders?
Deep injections are contraindicated
What teeth are innervated by the PSA?
Maxillary molars except the MB root of the first molar
What teeth are innervated by the MSA?
Premolars and MB root of first molar
What teeth are innervated by the ASA?
What nerves innervate the buccal soft tissues of maxillary teeth?
PSA, MSA, ASA
What nerve innervates the lingual soft tissues of teeth in the maxilla?
Anterior: nasopalatine nerve
Posterior: Greater palatine nerve
T/F: The needle tip should be past the apex of the tooth for infiltration.
What is the poi for a PSA block?
Height of MB fold over the second molar
T/F: There will be bone contact during a PSA block.
Insert about 1/2 of long needle and dispense
What is a common injury during needle insertion?
Pterygoid plexus hematoma
Where is the poi for a MSA block?
MB fold over 2nd premolar
What block will anesthetize the ASA, MSA, and infraorbital nerve?
Infraorbital nerve block
What is the poi for a infraorbital nerve block?
Over 1st premolar, should touch roof of the foramen
What are two important points for palatal injections?
1. Use topical
2. Pressure for blanching
Where is the POI for a greater palatine nerve block?
Just anterior to the GP foramen, often distal to second molar