Dentine hypersensitivity: Causes and mechanisms

Scanning electron microscope image of exposed dentine tubules

Exploring the causes of dentine hypersensitivity

Dentine hypersensitivity is a common dental problem that can develop over time. Here we take a closer look at the aetiology of dentine hypersensitivity and most widely accepted theory of how it arises.

The hydrodynamic theory of dentine hypersensitivity

Brännström’s hydrodynamic theory is currently the most commonly accepted theory of how dentine hypersensitivity arises:^1–4

Dentine hypersensitivity arises when tubules found within dentine become exposed, most commonly caused by gingival recession or enamel wear
Once exposed, these tubules may come into contact with stimuli, which can induce the movement of fluid within the tubules
Such movement can trigger nerves in the pulp, which may induce a short, sharp pain

Dentine exposure
How dentine tubules become exposed

Dentine tubules become exposed by gingival recession, due to:^3,5

Periodontal diseases

An over-vigorous brushing technique

Enamel wear exposes dentine tubules through one or more of the following:⁶

Erosion, commonly caused by acids or oesophageal reflux

Abrasion, i.e. enamel and dentine loss from excessive toothbrushing and/or other habits

Attrition (rarely), brought about by tooth grinding
Triggers

Dentine hypersensitivity triggers

Exposure of dentine tubules allows fluids within the tubules to move, which can be triggered by multiple types of stimuli.^3,4

1. Thermal stimuli

Cold (more likely), hot

2. Tactile stimuli

Toothbrushing

3. Osmotic stimuli

Sugary foods and drinks
Nerve stimulation

Nerve stimulation and pain

It is theorised that the rapid movement of fluid within dentine tubules triggered by external stimuli can stimulate the nerves within the dental pulp, causing pain.⁴