A patient complains of sharp, brief sensitivity to cold near the gingival margin of a recently scaled tooth. The pain subsides immediately when the cold stimulus is removed. What is the most likely diagnosis?

Reversible pulpitis is characterized by a sharp, localized pain that is elicited by stimuli (cold, sweet, pressure) and resolves immediately upon removal of the stimulus. The pulp retains its ability to recover. In this case, cold sensitivity at the gingival margin following scaling is consistent with reversible pulpitis caused by dentinal hypersensitivity — exposed root dentin tubules following removal of subgingival calculus and scaling. The hydrodynamic theory explains dentinal sensitivity: fluid movement in dentinal tubules stimulates Aδ nerve fibers. Irreversible pulpitis produces lingering pain (>30 seconds) after stimulus removal. Necrotic pulp is typically non-responsive to thermal stimulation. This presentation does not indicate irreversible disease.