Hydrodynamic theory

Hydrodynamic theory is a pain transmission theory of dentin. It states that various stimuli such as heat, cold, air blast desiccation, or mechanical or osmotic pressure affect fluid movement in the dentinal tubules. This fluid movement, either inward (due to cold stimuli) or outward (due to drying of exposed dentinal surface), stimulates the pain mechanism in the tubules by mechanical disturbance of the nerves closely associated with the odontoblast and its process. Thus these endings may act as mechanoreceptors as they are affected by mechanical displacement of the tubular fluid.

Consumption of acidic drinks e.g. vinegar, causes dental erosion and chemical stimulation

Most pain inducing stimuli increase centrifugal fluid flow within the dentinal tubules, giving rise to a pressure change throughout the entire dentin. This, in turn, activates the A-delta intradentinal nerves at the pulp–dentinal interface, or within the dentinal tubules thereby generating pain. Dentin sensitivity is seen more in patients with periodontal problems. The teeth most commonly affected are maxillary premolars followed by the maxillary first molars with the incisors being the least sensitive teeth. This theory explains pain throughout dentin since fluid movement will occur at the dentinoenamel junction as well as near the pulp. Erosion of peritubular dentin and smear plug removal accounts for dentin hypersensitivity caused by agents like acidic soft drinks. Brushing after acidic drink consumption induces smear layer formation, thus reducing sensitivity.

References

Hydrodynamic theory Resources
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