DH102 MIDTERM Study Guide

This set of flashcards covers key concepts from the DH102 Midterm Study Guide, focusing on pharmacology, bioavailability, and procedural aspects of local anesthetics.

Where is Prilocaine biotransformed (broken down)?

In the liver, kidneys, and lungs.

What are the two types of adrenergic receptors and which one predominates?

Alpha and Beta; Beta actions predominate.

Which organs are primarily affected by Beta 1 and Beta 2 receptors?

Beta 1 primarily affects the heart; Beta 2 primarily affects the lungs.

What is the single most important improvement in dental local anesthetic syringes?

The addition of the aspirating harpoon for safety reasons.

What does 'traveling down an axon in one direction toward the synapse' describe?

An action potential in a neuron.

Which nerve supplies innervation to the second & third maxillary molar?

The PSA (Posterior Superior Alveolar nerve).

What kind of action is required to have an electrical impulse cross the synapse?

The action can be electrical or chemical.

What are some responses a body could have to fear?

Increased blood pressure, muscular tension, anxiety, irritability, hyperventilation.

What is the most common topical preparation for Lidocaine?

5% Gel / ointment.

Which structures lose sensation when the anesthetic agent covers the lingual nerve?

Floor of the mouth, half of the tongue, lingual gingival tissues of the mandibular teeth.

What are the active ingredients used in Oraqix?

2.5% Lidocaine and 2.5% Prilocaine gel mixture which cannot be used in injectables.

What is the importance of the pKa number?

The pKa number determines the onset of action; lower numbers indicate faster onset.

How does the pain differ between lower pH and higher pH in tissues?

Lower pH (acidic) results in more comfortable injections but slower onset; higher pH (alkaline) leads to faster onset.

Which local anesthetic molecule improves lipid solubility for nerve membrane penetration?

The hydrophilic amino group.

What is the name of the connective tissue layer surrounding each axon?

Endoneurium.

Which local anesthetic is the most potent with the greatest lipid solubility?

Bupivacaine.

What factors influence the duration of local anesthetics effects?

Vascularity of the injection site, addition of a vasoconstrictor, degree of protein binding.

What is the nerve cell stage called when the cell is at rest at -70mv?

Polarization.

During what phase do the primary effects of local anesthetics occur?

Depolarization phase.

What positive ion is most abundant outside the plasma membrane in a resting neuron?

Sodium (Na+).

What is the most dilute concentration of epinephrine studied?

1:200,000 is the weakest dilution of epinephrine.

What should be done while waiting for local anesthetic to take effect?

Observe the patient for possible signs of an adverse reaction.

What are other names for an axon?

Nerve fibers, core bundles, mantle bundles.

What is true about topical anesthetics?

They are available in both esters and amides; 20% Benzocaine is an ester, and 5% Lidocaine is an amide.

List three advantages of topical anesthetic agents.

Useful for minor oral injuries, minimizes pain during needle insertion, reduces gag reflex.

What is a disadvantage of using topical anesthetic agents?

Risk of toxicity due to over-the-counter availability.

What determines the severity of an overdose reaction to local anesthetic?

Time lapse between administration and overdose symptoms.

Which solution in local anesthetic cartridges can trigger bronchospasms and allergies?

Sodium bisulfite.

What best practices should be followed when administering local anesthesia?

Limit application area, know drug concentration, review patient history, use lowest effective concentration.

Why is the pterygoid plexus a concern when giving the PSA?

It is highly vascular and can lead to adverse effects with intravascular injection.

Why are local anesthetics with vasoconstrictors more acidic than plain formulas?

Due to the presence of sodium bisulfite, which is acidic.

Which needle gauge provides the least deflection when penetrating tissues?

Larger-gauge needles.

What are causes of endogenous release of epinephrine?

Apprehension about dental appointments, anxiety, injections of epinephrine.

What is the predictability of anesthesia duration in inflamed versus healthy tissues?

Less predictable in inflamed tissues due to increased vascularity; more predictable in healthy tissues.

How many times should a clinician aspirate before administering local anesthetic?

Twice.

What part of the maxilla articulates with the zygomatic bone?

The zygomatic process.

What is the difference between motor and sensory neurons?

Sensory (Afferent) neurons carry signals to the spine/brain; Motor (Efferent) neurons carry signals away to muscles.

What is the most commonly used vasoconstrictor?

Epinephrine.

List effects of epinephrine.

Raises blood pressure, affects alpha and beta receptors, dilates bronchioles, constricts peripheral blood vessels.

Define elimination half-life.

The time for 50% of the anesthetic to be eliminated from the blood and tissues.

What is the maximum recommended dosage of epinephrine for healthy patients?

0.2 mg per appointment.

What are negative pressure and positive pressure in the context of syringes?

Negative pressure is created by pulling back the thumb ring; Positive pressure occurs when blood is drawn into the cartridge.

How long should it take to deposit one cartridge of anesthetic?

Around 1.8 ml per 2 minutes.

What is the purpose of the colored band on a cartridge?

It signifies the anesthetic drug inside the cartridge.

What do local anesthetic drugs inhibit to prevent nerve cell stimulation?

Sodium influx.

What solution was used to prevent bacterial growth in local anesthetic?

Methylparaben.

What is true about Benzocaine?

20% Benzocaine gel is preferred as a topical anesthetic; it is not water soluble.

What is the significance of the Periodontal Ligament Injection?

It is used for reliable anesthesia of one tooth in the mandible.

What are the Nodes of Ranvier?

Gaps in myelinated nerve fibers where anesthetic can diffuse and take effect.

What is hemostasis?

The stopping of blood flow, effective with 1:100,000 epi.

What is the difference between relative and absolute contraindications for local anesthetics?

Relative indicates a careful risk-benefit balance, while absolute means local anesthetics must not be used.

Where is the excretion of local anesthetics primarily occur?

Mostly in the kidneys.

Which local anesthetics have the least vasodilatory properties?

Mepivacaine (plain) and Prilocaine (plain).

What happens to blood vessels immediately after a plain local injection?

Vasodilation and increased blood flow at the injection site.

What determines if a local anesthetic is an ester or amide?

The intermediate carbon chain.

How should local anesthetic cartridges be stored?

At room temperature.

How long does 2% Lidocaine with epi provide pulpal anesthesia?

60 minutes.

What solutions are available for Mepivacaine?

3% Mepivacaine plain and 2% Mepivacaine with levonordefrin 1:20,000.

What is another name for a vasopressor?

Vasoconstrictor.

What is the difference between hypo-responder and hyper-responder?

Hypo-responders experience shorter anesthesia duration; hyper-responders experience longer duration.

What does 'Gauge' refer to in needles?

The diameter of the needle lumen.

What are the gauges used in dentistry and what do they signify?

25-, 27-, and 30-gauge needles; larger gauge numbers mean smaller lumens.

What should be done with needles after several penetrations?

Needles should be changed every 3-4 penetrations.

What type of gas bubble is found under the cartridge cap?

A nitrogen gas bubble.

What are clinical observations of Methemoglobinemia?

Bluish skin tone and lips; requires Methylene Blue IV for reversal.

Where are esters and amides metabolized?

Esters are metabolized in blood plasma; amides are metabolized in the liver.

Why is severe liver disease a contraindication for local anesthetic administration?

Poor metabolism of the anesthetic raises the risk of overdose.

Which anesthetic should be used with patients who have uncontrolled hyperthyroid disease?

Any anesthetic with epinephrine.

Which nerve fibers have the fastest conduction velocity?

Large and myelinated nerve fibers.

What anesthetic is chosen for a patient sensitive to epinephrine needing 30 minutes of pulpal anesthesia?

3% Mepivacaine plain.

How much time does 4% Articaine with 1:200,000 epinephrine provide for pulpal anesthesia?

60 – 75 minutes.

Do local anesthetics cross the placenta and blood-brain barriers?

Yes.