Sensitivity: Causes and mechanisms
What causes 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.
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 dietary 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.
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
3. Osmotic stimuli
Sugary foods and drinks
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