Hydrodynamic theory (dentistry)
The Hydrodynamic or Fluid Movement theory is one of the main theories in dentistry to explain the mechanism by which a tooth perceives the sensation of pain. It is currently the most widely accepted theory used to explain tooth sensitivity.
There are three main theories of dentine hypersensitivity:
- Direct Innervation Theory
- Odontoblast Receptor Theory
- Fluid Movement/Hydrodynamic Theory
The hydrodynamic theory, first proposed by M. Brännström in 1966, suggested that dentine hypersensitivity is due to the abrupt movement of fluid within the dentinal tubules in response to cold and heat, osmotic, mechanical and evaporative stimuli.
Cold, osmotic and evaporative stimuli cause an outward flow of fluid and mechanical and hot stimuli cause an inward flow.
The movement of dentinal fluid leads to mechanical deformation and activation of the sensory nerve terminals of low-threshold Aδ fibres located in close contact with odontoblasts
