Tooth sensitivity is actually a very common problem caused by several factors as we shall see. It can be treated and to an extent prevented. Tooth sensitivity can be experienced by young and old alike. However, the elderly are more prone as we shall soon learn. The teeth consist of three layers. The uppermost is the hardest and is known as enamel. Beneath the enamel is the softer yellowish layer known as dentin. The third layer is the pulp, which is the centre of the tooth. The pulp is also where you find the nerve endings as well as the blood vessels which supply the tooth with all its needs. Tooth sensitivity is caused by the gradual exposure of dentin by any number of means. One common means is through cavities, but over-consumption of carbonated beverages can also produce this. Now, dentin has microscopic channels which are filled with fluid and contain nerve endings which extend into the pulp. Eating or drinking foods and beverages hot, cold or sweet can cause this fluid to move which in turn causes the nerve endings to react in response. This causes the sudden discomfort or an acute, but transient sharp pain.