LOCAL ANESTHESIA - CDCA BOARD EXAM ACTUAL 2025/2026
QUESTIONS AND 100% CORRECT ANSWERS | VERIFIED |
GRADED A+
EXAM OVERVIEW .
This comprehensive study guide is designed for candidates preparing for the CDCA Local Anesthesia Board Exam
for the 2025/2026 testing cycle. The examination is administered through ADEX (American Dental Examinations,
Inc.) and is required for dental hygiene and dental licensure in participating jurisdictions.
Exam Information:
• Exam Provider: CDCA-WREB-CITA (Commission on Dental Competency Assessments)
• Reference Materials: Candidates are responsible for understanding content in the Candidate Guide,
Candidate Manual, and clinical examination forms
• Required Textbook: Logothetis, Local Anesthesia for the Dental Hygienist, 3rd Edition (Elsevier)
• Course Preparation: Typically requires 40-80 hours of combined online self-study, interactive
presentations, and 3-day clinical training with 30+ injection experiences
Major Content Areas Covered:
• Neurophysiology and nerve conduction
• Pharmacology of local anesthetics and vasoconstrictors
• Anatomic landmarks and injection techniques
• Patient assessment and medical considerations
• Dosage calculations and maximum safe doses
• Local and systemic complications management
Section 1: Neurophysiology and Pain Pathways (Questions 1-20)
Q1: Describe the polarization of a nerve cell at rest:
• A. Inside positive, outside negative, with a difference of approximately +70 mV
• B. Inside negative, outside positive, with a difference of approximately -70 mV
• C. Inside neutral, outside positive, with no measurable difference
• D. Inside positive, outside neutral, with a difference of approximately -50 mV
Correct Answer: B [CORRECT]
,Rationale:
• At resting potential, the inside of the nerve cell is slightly negative (-70 mV) and the outside is slightly
positive due to differential distribution of ions (Na+ predominantly outside, K+ predominantly inside).
Q2: What event occurs during depolarization of a nerve cell?
• A. Potassium ions (K+) rapidly enter the cell, making the inside more positive
• B. Sodium ions (Na+) rapidly enter the cell, making the inside more positive
• C. Chloride ions (Cl-) rapidly exit the cell, making the inside more negative
• D. Calcium ions (Ca2+) rapidly enter the cell, stabilizing the membrane
Correct Answer: B [CORRECT]
Rationale:
• Depolarization occurs when voltage-gated sodium channels open, allowing Na+ to flow into the cell,
reversing the polarity and making the inside positive (+30 to +40 mV).
Q3: What event occurs during repolarization of a nerve cell?
• A. Sodium ions (Na+) are pumped back out of the cell
• B. Potassium ions (K+) leave the cell to restore equilibrium
• C. Calcium ions (Ca2+) enter the cell to stabilize the membrane
• D. Chloride ions (Cl-) enter the cell to reset the potential
Correct Answer: B [CORRECT]
Rationale:
• Repolarization begins immediately after depolarization with potassium ions (K+) leaving the cell through
voltage-gated K+ channels, restoring the negative resting membrane potential.
Q4: Myelinated nerves conduct impulses _________ with _________ energy compared to unmyelinated nerves.
• A. slower; more
• B. faster; less
• C. slower; less
• D. faster; more
Correct Answer: B [CORRECT]
,Rationale:
• Myelinated nerves conduct impulses faster with less energy due to saltatory conduction, where impulses
jump from node to node (nodes of Ranvier) rather than traveling continuously along the membrane.
Q5: What do the nodes of Ranvier on myelinated nerves allow for?
• A. Faster nerve regeneration after injury
• B. The passage of local anesthesia into the nerve cell
• C. Increased production of neurotransmitters
• D. Protection of the nerve from mechanical trauma
Correct Answer: B [CORRECT]
Rationale:
• The nodes of Ranvier are gaps in the myelin sheath that allow local anesthetic molecules to penetrate the
nerve cell membrane and access sodium channels. They enable saltatory conduction.
Q6: What is the primary mechanism of action of local anesthetics?
• A. Blocking potassium channels to prevent repolarization
• B. Blocking sodium channels to prevent depolarization
• C. Enhancing GABA receptors to inhibit nerve transmission
• D. Blocking calcium channels to prevent neurotransmitter release
Correct Answer: B [CORRECT]
Rationale:
• Local anesthetics work primarily by blocking voltage-gated sodium channels from the inside of the nerve
membrane, preventing sodium influx and thus blocking depolarization and propagation of action
potentials.
Q7: What is saltatory conduction?
• A. The process of nerve regeneration after injury
• B. The transmission of pain signals through unmyelinated C-fibers
• C. The process of nerve impulses jumping from node to node along a myelinated nerve
• D. The gradual decrease in nerve impulse strength over distance
, Correct Answer: C [CORRECT]
Rationale:
• Saltatory conduction (from Latin "saltare" meaning to leap) refers to the jumping of action potentials
from one node of Ranvier to the next along myelinated nerves, which increases conduction velocity up to
100x faster than unmyelinated fibers.
Q8: What molecules are predominantly outside and inside the nerve cell at resting potential?
• A. K+ outside, Na+ inside
• B. Na+ outside, K+ inside
• C. Ca2+ outside, Cl- inside
• D. Cl- outside, Na+ inside
Correct Answer: B [CORRECT]
Rationale:
• At resting potential, sodium (Na+) is predominantly outside the cell (extracellular concentration ~145
mM) and potassium (K+) is predominantly inside the cell (intracellular concentration ~140 mM),
maintained by the Na+/K+ ATPase pump (3 Na+ out, 2 K+ in).
Q9: Which nerve fibers are typically blocked first by local anesthetics?
• A. Motor fibers (A-alpha)
• B. Sympathetic fibers (B fibers)
• C. Sensory fibers carrying pain and temperature (C and A-delta fibers)
• D. Proprioceptive fibers (A-beta)
Correct Answer: C [CORRECT]
Rationale:
• The differential blockade occurs where smaller, lightly myelinated (A-delta) and unmyelinated (C) fibers
carrying pain and temperature are blocked first. Motor function (large A-alpha fibers) is blocked last. This
order relates to fiber size and myelination.
Q10: What is the approximate resting membrane potential of a typical nerve cell?
• A. -30 mV
• B. -50 mV
QUESTIONS AND 100% CORRECT ANSWERS | VERIFIED |
GRADED A+
EXAM OVERVIEW .
This comprehensive study guide is designed for candidates preparing for the CDCA Local Anesthesia Board Exam
for the 2025/2026 testing cycle. The examination is administered through ADEX (American Dental Examinations,
Inc.) and is required for dental hygiene and dental licensure in participating jurisdictions.
Exam Information:
• Exam Provider: CDCA-WREB-CITA (Commission on Dental Competency Assessments)
• Reference Materials: Candidates are responsible for understanding content in the Candidate Guide,
Candidate Manual, and clinical examination forms
• Required Textbook: Logothetis, Local Anesthesia for the Dental Hygienist, 3rd Edition (Elsevier)
• Course Preparation: Typically requires 40-80 hours of combined online self-study, interactive
presentations, and 3-day clinical training with 30+ injection experiences
Major Content Areas Covered:
• Neurophysiology and nerve conduction
• Pharmacology of local anesthetics and vasoconstrictors
• Anatomic landmarks and injection techniques
• Patient assessment and medical considerations
• Dosage calculations and maximum safe doses
• Local and systemic complications management
Section 1: Neurophysiology and Pain Pathways (Questions 1-20)
Q1: Describe the polarization of a nerve cell at rest:
• A. Inside positive, outside negative, with a difference of approximately +70 mV
• B. Inside negative, outside positive, with a difference of approximately -70 mV
• C. Inside neutral, outside positive, with no measurable difference
• D. Inside positive, outside neutral, with a difference of approximately -50 mV
Correct Answer: B [CORRECT]
,Rationale:
• At resting potential, the inside of the nerve cell is slightly negative (-70 mV) and the outside is slightly
positive due to differential distribution of ions (Na+ predominantly outside, K+ predominantly inside).
Q2: What event occurs during depolarization of a nerve cell?
• A. Potassium ions (K+) rapidly enter the cell, making the inside more positive
• B. Sodium ions (Na+) rapidly enter the cell, making the inside more positive
• C. Chloride ions (Cl-) rapidly exit the cell, making the inside more negative
• D. Calcium ions (Ca2+) rapidly enter the cell, stabilizing the membrane
Correct Answer: B [CORRECT]
Rationale:
• Depolarization occurs when voltage-gated sodium channels open, allowing Na+ to flow into the cell,
reversing the polarity and making the inside positive (+30 to +40 mV).
Q3: What event occurs during repolarization of a nerve cell?
• A. Sodium ions (Na+) are pumped back out of the cell
• B. Potassium ions (K+) leave the cell to restore equilibrium
• C. Calcium ions (Ca2+) enter the cell to stabilize the membrane
• D. Chloride ions (Cl-) enter the cell to reset the potential
Correct Answer: B [CORRECT]
Rationale:
• Repolarization begins immediately after depolarization with potassium ions (K+) leaving the cell through
voltage-gated K+ channels, restoring the negative resting membrane potential.
Q4: Myelinated nerves conduct impulses _________ with _________ energy compared to unmyelinated nerves.
• A. slower; more
• B. faster; less
• C. slower; less
• D. faster; more
Correct Answer: B [CORRECT]
,Rationale:
• Myelinated nerves conduct impulses faster with less energy due to saltatory conduction, where impulses
jump from node to node (nodes of Ranvier) rather than traveling continuously along the membrane.
Q5: What do the nodes of Ranvier on myelinated nerves allow for?
• A. Faster nerve regeneration after injury
• B. The passage of local anesthesia into the nerve cell
• C. Increased production of neurotransmitters
• D. Protection of the nerve from mechanical trauma
Correct Answer: B [CORRECT]
Rationale:
• The nodes of Ranvier are gaps in the myelin sheath that allow local anesthetic molecules to penetrate the
nerve cell membrane and access sodium channels. They enable saltatory conduction.
Q6: What is the primary mechanism of action of local anesthetics?
• A. Blocking potassium channels to prevent repolarization
• B. Blocking sodium channels to prevent depolarization
• C. Enhancing GABA receptors to inhibit nerve transmission
• D. Blocking calcium channels to prevent neurotransmitter release
Correct Answer: B [CORRECT]
Rationale:
• Local anesthetics work primarily by blocking voltage-gated sodium channels from the inside of the nerve
membrane, preventing sodium influx and thus blocking depolarization and propagation of action
potentials.
Q7: What is saltatory conduction?
• A. The process of nerve regeneration after injury
• B. The transmission of pain signals through unmyelinated C-fibers
• C. The process of nerve impulses jumping from node to node along a myelinated nerve
• D. The gradual decrease in nerve impulse strength over distance
, Correct Answer: C [CORRECT]
Rationale:
• Saltatory conduction (from Latin "saltare" meaning to leap) refers to the jumping of action potentials
from one node of Ranvier to the next along myelinated nerves, which increases conduction velocity up to
100x faster than unmyelinated fibers.
Q8: What molecules are predominantly outside and inside the nerve cell at resting potential?
• A. K+ outside, Na+ inside
• B. Na+ outside, K+ inside
• C. Ca2+ outside, Cl- inside
• D. Cl- outside, Na+ inside
Correct Answer: B [CORRECT]
Rationale:
• At resting potential, sodium (Na+) is predominantly outside the cell (extracellular concentration ~145
mM) and potassium (K+) is predominantly inside the cell (intracellular concentration ~140 mM),
maintained by the Na+/K+ ATPase pump (3 Na+ out, 2 K+ in).
Q9: Which nerve fibers are typically blocked first by local anesthetics?
• A. Motor fibers (A-alpha)
• B. Sympathetic fibers (B fibers)
• C. Sensory fibers carrying pain and temperature (C and A-delta fibers)
• D. Proprioceptive fibers (A-beta)
Correct Answer: C [CORRECT]
Rationale:
• The differential blockade occurs where smaller, lightly myelinated (A-delta) and unmyelinated (C) fibers
carrying pain and temperature are blocked first. Motor function (large A-alpha fibers) is blocked last. This
order relates to fiber size and myelination.
Q10: What is the approximate resting membrane potential of a typical nerve cell?
• A. -30 mV
• B. -50 mV
