Full-Mouth Pulpal Diagnosis

Correct answer: C. Symptomatic irreversible pulpitis

• A. The pulpal response is clearly abnormal, so the pulp is not normal.
• B. A necrotic pulp gives no response to cold at all.
• C. Correct. A thermal response that lingers beyond about 10–20 seconds signals inflammation that will not resolve — symptomatic irreversible pulpitis. Root canal therapy or extraction is indicated.
• D. Reversible pulpitis produces a sharp response that disappears as soon as the stimulus is removed.

Correct answer: B. Pulp necrosis with symptomatic apical periodontitis

• A. There is no history or radiographic evidence of previous endodontic treatment.
• B. Correct. No response to cold indicates necrosis; pain on percussion and palpation with a periapical radiolucency indicates symptomatic apical periodontitis.
• C. Irreversible pulpitis requires a vital, responsive pulp — this pulp does not respond.
• D. Reversible pulpitis cannot coexist with a non-responsive pulp and apical breakdown.

Correct answer: B. Reversible pulpitis

• A. Asymptomatic irreversible pulpitis is diagnosed when there are no symptoms but the pulp is judged incapable of healing, often after caries excavation exposes the pulp.
• B. Correct. An exaggerated response that resolves promptly once the stimulus is removed is the definition of reversible pulpitis. Removing the irritant — here the deep restoration and any caries — should resolve it.
• C. A normal pulp gives a response proportional to the stimulus, not an exaggerated one.
• D. The absence of lingering is what separates this from irreversible pulpitis.

Correct answer: A. Symptomatic apical periodontitis

• A. Correct. Pain to biting and percussion with apical radiographic change and no swelling or drainage defines symptomatic apical periodontitis.
• B. An acute apical abscess adds rapid onset, swelling, and often systemic signs such as fever and malaise.
• C. Condensing osteitis is a radiopaque, not radiolucent, response to low-grade pulpal irritation.
• D. A chronic apical abscess is characteristically asymptomatic and drains through a sinus tract.

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.

Correct answer: D. C fibers

• A. A-alpha fibers are large motor and proprioceptive fibers, not pulpal nociceptors.
• B. Sympathetic fibers regulate pulpal blood flow rather than transmitting nociception.
• C. A-delta fibers mediate the sharp cold and EPT response, not the heat response.
• D. Correct. C fibers have a high threshold and are activated as inflammation and intrapulpal pressure rise, producing the dull, lingering, heat-provoked pain typical of advanced pulpitis.