Tooth sensitivity occurs when dentin becomes exposed. This may occur through loss of tooth enamel (dentin is the layer of the tooth underneath the enamel). For example, brushing the teeth and gum line too hard or using a hard-bristled toothbrush instead of a soft or medium toothbrush may wear away tooth enamel causing toothbrush abrasion. In addition, enamel erosion, loss of tooth structure, can occur as a result of consuming acidic foods. It may also occur as a result of gum recession and loss of the underlying cementum, which exposes the root surface. When dentin is exposed to an external stimulus, such as heat or cold, pressure, or sweet and sour foods and drinks, a person may feel discomfort and sometimes a sharp pain in the tooth or teeth.
There are several conditions that give rise to pain, but that are not tooth sensitivity:
There are microscopic tubular structures in the dentin that radiate outward from the pulp of the tooth, which provides the tooth with blood and nutrients, to the external surface of the dentin. These tubules also contact the nerve fibers within the pulp. When dentin tubules are exposed and they experience an external stimulus, such as heat, cold, a change in pressure, or sweet or sour foods and drinks, the stimulus creates a change in dentin fluid flow that is transmitted to the nerve fibers where it is perceived as the pain of tooth sensitivity.
Talk to your dentist if you think you have tooth sensitivity so that he or she can provide the correct diagnosis and recommend options for treatment.
1 Fischer C, Fischer RG, Wennberg A: Prevalence and distribution of cervical dentine hypersensitivity in a population in Rio De Janiero, Brazil, J Dent 20:272.