Endodontics · patient case question
Which nerve fibers are responsible for the sensation elicited by an electric pulp test?
Patient case: Full-Mouth Pulpal Diagnosis
demo: 46-year-old female
chief: “Several of my teeth on the upper right have been bothering me in different ways.”
history: Non-contributory. No medications.
meds: None
findings: Tooth #2: no response to cold, painful to percussion and palpation, periapical radiolucency. Tooth #3: sharp pain to cold that lingers more than 20 seconds. Tooth #4: exaggerated but non-lingering response to cold, deep restoration. Tooth #5: pain on biting, tender to percussion, widened PDL at the apex.
Show answer and explanation
Correct answer: C. A-delta fibers
- A. B fibers are preganglionic autonomic fibers and play no role in pulp testing.
- B. A-beta fibers carry touch and pressure from skin and are not the pulpal responders in an EPT.
- C. Correct. Myelinated A-delta fibers in the pulp–dentin border respond to the electrical stimulus and to cold, producing sharp, well-localized, brief pain.
- D. Unmyelinated C fibers are responsible for the dull, poorly localized, throbbing pain and for the response to heat — they are not activated by a standard EPT.