More than 40% of adults experience tooth sensitivity, also referred to as dentin hypersensitivity. It occurs more frequently in women than in men. (1), (2), (3) Most people experience tooth sensitivity as a short, sharp pain originating from a tooth or teeth in their mouth.
Why Does Tooth Sensitivity Occur?
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 center of the tootth 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). Enamel loss is more prominent when brushing occurs immediately before or soon after consumption of acidic foods (fruits, tomatoes) and drinks that cause tooth erosion.
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 center 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.