Dentin Hypersensitivity: Causes and mechanisms

Scanning electron microscope image of exposed dentin tubules

What causes dentin hypersensitivity?

Dentin hypersensitivity is a common dental problem that can develop over time. Here we take a closer look at the aetiology of dentin hypersensitivity.

The hydrodynamic theory of dentin hypersensitivity

Brännström’s hydrodynamic theory is currently the most commonly accepted theory of how dentin hypersensitivity arises:1,2

  • Dentin 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 such as hot, cold and sweet foods and drinks, 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
  • Dentin exposure

    Causes of exposed dentin

    How dentin tubules become exposed

    Dentin tubules become exposed by gingival recession, due to:3

    • Periodontal diseases
    • An over-vigorous brushing technique

    Tooth wear processes expose dentin tubules through one or more of the following:4

    • Erosion (chemical breakdown of enamel) – contributing factors include exogenous acids (dietary acids), endogenous acids (gastroesophogeal reflux)
    • Abrasion (mechanical wear) – contributing factors include incorrect toothbrushing i.e. brushing too hard and improper oral hygiene
    • Attrition (loss of tooth structure due to tooth-on-tooth contact) – contributing factors tooth clenching or grinding

    Read more about enamel wear

    Whitening treatments

    Research indicates that 55-75% of patients experience sensitivity after professional whitening treatments.5 Certain at-home whitening methods can also trigger sensitivity.6 While sensitivity experienced due to whitening treatments differs from dentin hypersensitivity, clinical studies have shown that toothpastes containing potassium nitrate, like Sensodyne, can reduce the sensitivity caused by whitening procedures.5

  • Triggers

    Dentin hypersensitivity triggers  

    Exposure of dentin tubules allows fluids within the tubules to move, which can be triggered by multiple types of stimuli.1,2

    hot drink

    Thermal stimuli

    Cold (more likely), hot

    Tactile stimuli

    Tactile stimuli

    Tooth brushing

    Sweet foods

    Osmotic stimuli

    Sugary foods and drinks

  • Nerve stimulation

    Tooth cross section

    Nerve stimulation and pain

    It is theorized that the rapid movement of fluid within dentin tubules triggered by external stimuli can stimulate the nerves within the dental pulp, causing pain.1,2

SENSODYNE – #1 Dentist recommended brand for sensitive teeth7

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