Tooth sensitivity or dentin hypersensitivity is a very common condition that affects more than 45 million adults in the U.S.

Sensitivity is experienced as a sharp pain, and it is triggered by eating hot or cold foods, drinking hot or cold beverages, breathing cold air, or eating sugary or acidic foods.

This occurs when the enamel is worn down or if the gum line is recessed. In both cases the dentin (the layer below the enamel in the crown of the tooth) is exposed.

There are several reasons dentin can be exposed, leading to sensitivity.

• Gum recession as a result of age or brushing too hard can cause tooth sensitivity. Gum disease can cause gum recession.

• Acidic beverages can cause enamel to erode, thus exposing the dentin.

• Tooth grinding can cause sensitivity because enamel erodes, exposing dentin. This can cause most or all teeth to feel sensitive.

• Brushing with abrasive toothpaste, brushing too hard or brushing more than three times a day could wear down enamel.

• A chipped or fractured tooth may expose the dentin and cause sensitivity.