A patient has sensitivity in tooth #28 after a well-executed restoration in tooth #29. Tooth #28 is unrestored with 3 mm of recession. What is the MOST likely explanation?

Correct answer: B. Referred pain from tooth #29

• A. Occlusal trauma would show wear facets, fremitus, or a high spot, and would have been present before the restorative appointment.
• B. CORRECT. Pulpal pain is poorly localized because pulpal afferents converge on shared second-order neurons in the trigeminal spinal nucleus. Pain from one tooth is therefore commonly REFERRED to an adjacent tooth or across the arch — most often within the same quadrant, and rarely across the midline. When the symptomatic tooth is sound and its neighbor has just been treated, referred pain from the treated tooth is the parsimonious explanation. Selective anesthesia will confirm it.
• C. An unrestored tooth with no caries has no obvious route to pulp necrosis, and necrosis would not produce thermal sensitivity.
• D. A crack would produce pain on release of biting pressure, and typically has a history predating the restoration.

Note: Selective anesthesia is your diagnostic tool: anesthetize the suspect tooth and see whether the pain disappears.