Cavities and fractured teeth can cause sensitive teeth. But if your dentist has ruled these problems out, then worn tooth enamel, a cracked tooth or an exposed tooth root may be the cause.

Your teeth contain small hollow tubes or canals, called dentin, that when it loses its protective covering allow heat and cold or acidic or sticky foods to stimulate the nerves and cells inside the tooth. This causes hypersensitivity and occasional discomfort. Fortunately, the irritation does not cause permanent damage to the pulp. Dentin may be exposed when gums recede. The result can be hypersensitivity near the gum line.

Proper oral hygiene is the key to preventing gums from receding and causing sensitive-tooth pain. If you brush your teeth incorrectly or even over-brush, gum problems can result. Ask your dentist if you have any questions about your daily oral hygiene routine.

Tooth sensitivity is caused by the movement of fluid within tiny tubes located in the dentin, which is the layer of tissue beneath the hard enamel that contains the inner pulp of the tooth. This can irritate the tooth's nerve. When the hard enamel is worn down or gums have receded, these tiny tube surfaces can become exposed.

Pain can result from eating or drinking hot or cold foods and beverages, touching your teeth, or exposing them to cold air. Taking a spoonful of ice cream, for example, can be a painful experience for people with sensitive teeth.