Tooth #2 tests NEGATIVE to cold but is painful on percussion and palpation. What is the diagnosis?

Correct answer: A. Pulp necrosis with symptomatic apical periodontitis

• A. CORRECT. A negative response to cold indicates the pulp is NECROTIC — there are no viable A-delta fibers left to respond. Pain on PERCUSSION and PALPATION indicates that inflammation has extended beyond the apex into the periodontal ligament, which is SYMPTOMATIC APICAL PERIODONTITIS. The combination — no pulpal response plus periapical tenderness — is the classic pairing, and treatment is root canal therapy or extraction.
• B. Symptomatic irreversible pulpitis requires a VITAL pulp with an exaggerated, LINGERING response to cold (over 20–30 seconds). This tooth gives no response at all.
• C. A normal pulp responds to cold with a brief, non-lingering sensation and has no percussion tenderness.
• D. Reversible pulpitis is a vital pulp with a sharp, brief response that resolves on removal of the stimulus.

Note: Pulpal test tells you about the PULP; percussion and palpation tell you about the PERIAPEX. Every endodontic diagnosis needs both halves.