Dentin hypersensitivity (DH, DHS) is dental pain which is sharp in character and of short duration, arising from exposed dentin surfaces in response to stimuli, typically thermal, evaporative, tactile, osmotic, chemical or electrical; and which cannot be ascribed to any other dental disease.

Source : Wikipedia

The most common form is dental sensitivity to cold temperatures - which, depending on the study, has been reported in 4% to 74% of people (note margin of error). It can affect any age-group.

The cause of dentine sensitivity has been extensively investigated - and there are currently several competing theories. Including the 'direct innervation theory' the ‘odontoblast receptor theory’, and the ‘hydrodynamic theory’ - that latter of which is the most commonly accepted. For details see :Journal of Conserv Dent. 13(4): 218–224

Also see :Desensitizing toothpastesplugin-autotooltip__plain plugin-autotooltip_bigDesensitizing toothpastes

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Note: This article is currently in the 'proposed content' section.

Several brands of toothpaste attempt to desensitize exposed dentine (see Dentin hypersensitivity). They typically use potassium nitrate, potassium chloride or potassium citrate. They can be an effective 'home treatment' - but the 'mechanism of action' has not been definitively confirmed