Dentine hypersensitivity is caused by exposure of the dentine layer of the tooth. Normally, the soft dentine is protected by either the gums around the roots or the hard dental enamel at the crown. Dentine has tubules, or narrow channels, that lead to the pulp of the tooth, where the nerve fibres are located. When external stimuli can reach these tubuli, they can stimulate the nerve fibres and are registered as pain.
The major cause for exposed dentine is recession of gum tissue. When the gums receed, they expose the dental neck where the dentine is only protected by a thin layer of cementum which is easily removed.
Enamel loss can also lead to dentine hypersensitivity when the complete enamel layer protecting the underlying dentine is removed through erosion, abrasion or attrition.
Dentine hypersensitivity pain can be triggered by a number of external stimuli. Common triggers include:
- Hot, cold, sugary or acidic foods and drinks.
- Cold air.
- Tactile, e.g. toothbrushing or scratching over the exposed dentine surface.
Dentine hypersensitivity is common but underreported, so it is difficult to accurately measure incidence. However, studies estimate that prevalence can be up to 60%. Whilst the risk for exposed dentine increases with age, dentine hypersensitivity peaks usually around the age 30 to 40 as the tubulies can naturally clog up.