Teeth are sensitive if they often hurt when they are exposed to cold or to air.
You may also feel discomfort or a sud- den flash of pain when eating sweet, acidic, or hot foods. The pain you feel may be due to receding gums, worn tooth enamel, or worn root surfaces. Healthy teeth are protected by strong enamel and good gums. When enamel erodes or gums recede, dentin can be exposed. Dentin is the layer of the tooth that is normally covered by the enamel and gums.