A patient has pain in the upper right first premolar that wakes them up at night. Cold test produces lingering pain lasting more than 12 seconds. The tooth is tender to percussion. What is the diagnosis?

Correct answer: A. Irreversible pulpitis with symptomatic apical periodontitis

• A. Correct. Lingering pain to cold (>12 seconds) indicates irreversible pulpitis (IP). Tenderness to percussion indicates periapical inflammation — symptomatic apical periodontitis (SAP). The combination of IP + SAP is a complete clinical diagnosis and indicates root canal treatment is needed.
• B. Reversible pulpitis presents with brief, transient cold sensitivity — not lingering pain or percussion tenderness.
• C. Cracked tooth syndrome typically has pain on biting/releasing, not continuous nocturnal pain with cold hypersensitivity.
• D. Pulp necrosis presents with NO response to cold (absent cold response) — the positive cold response here indicates live (albeit diseased) pulp tissue.