More than 40% of adults experience tooth sensitivity, also referred to as dentin hypersensitivity. According to a research report published in the Journal of Conservative Dentistry, dentinal hypersensitivity is a common clinical condition usually associated with exposed dentinal surfaces. It can affect patients of any age group. A slightly higher incidence of dentinal hypersensitivity has been reported in females than in males. While dentinal hypersensitivity can affect the patient of any age, most affected patients are in the age group of 20-50 years, with a peak between 30 and 40 years of age.
Each tooth contains four parts. The enamel comprises the visible crown of the tooth and is the hardest layer of the tooth containing the highest level of calcium phosphate mineral). The dentin is the layer below the enamel in the crown of the tooth, and below the cementum in the root. It is softer than the enamel, but stronger than the cementum. The cementum is present on the root surface to help anchor the teeth into the jaw. The pulp is in the centre of the tooth and contains soft connective tissue, blood vessels, and nerves).
Major factors that lead to tooth sensitivity are gum recession and loss of cementum, and loss of enamel. Gum recession (gum moving down from the gum line, exposing the root dentin surface) can be caused by loss of periodontal attachment as a result of periodontal disease or by brushing too hard causing gum abrasion. Loss of enamel, on the other hand, occurs when the toothbrush abrades or wears down the enamel surface and exposes the underlying dentin (the layer underneath the enamel).
When the enamel is worn down, or the gum line is recessed, exposing the dentin, tooth sensitivity can occur. The dentin contains tubules that run from the centre of the tooth, i.e., the pulp, which contains the nerves of the tooth, to the exposed dentin surface.
When the dentin is exposed, dentin fluid flows outward from the pulp. If this flow is perturbed by exposure to an external stimulus, such as heat, cold, change in pressure, sweet or sour foods and drinks, a signal id transmitted to the nerves which is perceived as pain.