Hydrodynamic Theory — NDEB AFK MCQ
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Correct answer: A — Hydrodynamic theory (Brännström)
The hydrodynamic theory (Brännström, 1964) is the most widely accepted explanation for dentin hypersensitivity. It proposes that external stimuli (cold, air, osmotic, tactile) cause rapid fluid movement within exposed dentinal tubules, which activates mechanoreceptors (A-delta nerve fibres) at the pulp-dentin border, producing a sharp pain. This explains why factors that open tubules (acid erosion, abrasion, gingival recession) increase sensitivity, while factors that occlude tubules (desensitising agents, smear layer, fluoride varnish) reduce it.
Reference: Heymann – Sturdevant's Art and Science of Operative Dentistry, 7th ed., 2019