Drinking hot and cold beverages, eating sweet or acidic foods, brushing your teeth, breathing through your mouth, biting down—if any of these normal activities are causing you pain, you’re probably experiencing tooth sensitivity.

Tooth anatomy helps explain why teeth can become sensitive:

• Enamel covers the crown, the visible part of the tooth above the gum line. Enamel is composed primarily of minerals and is the hardest substance in the body. Intact enamel protects the vulnerable tissues inside the tooth.
• Cementum covers the roots of the tooth and, while quite strong, is more porous and softer than enamel.
• Dentin lies just beneath the outer enamel and cementum. It’s a softer tissue filled with microscopic tubules that are connected to the pulp. When damaged enamel or cementum expose part of the dentin layer, the tooth becomes sensitive to things like temperature, sugars and acids, and touch.
• Inside the tooth and protected by the dentin layer are the pulp chamber and root canals. These are filled with pulp, living tissue composed of nerves, blood vessels, and connective tissue. If the pulp is damaged, the blood vessels inside become inflamed, putting pressure on the nerves and causing pain. Infection can set in, destroying pulp tissue and spreading to the surrounding gums and bone.

What causes sensitivity?

Sensitivity is a symptom that the tooth is compromised. You should see your dentist promptly to discover the source of and treatment for your discomfort.

• Tooth Decay

When a cavity is deep enough to penetrate the enamel and reach the dentin, sharp pain when eating certain foods, drinking hot or cold beverages, breathing through the mouth, or brushing can result. Sensitivity can also be a sign that a loose or broken filling needs replacement. Treating a cavity in its early stages or replacing a damaged filling right away prevents decay from reaching the inner pulp and endangering the tooth.

• Infection

Once decay has reached the pulp, the tooth is vulnerable to infection. This infection can spread to bone and gum tissue. Because the inner pulp contains nerves, infected and inflamed pulp can be very painful. Root canal treatment is often necessary to save the tooth.

• Trauma

A chip, crack, or fracture can damage tooth structure and expose dentin and pulp to bacteria. You should see your dentist immediately after any dental trauma. Crown, onlays, veneers, or other restorations can repair injured teeth and prevent further damage.

• Gum Disease

Periodontitis causes the gums to pull away from the teeth, exposing portions of the cementum covering the roots. Cementum is softer than enamel, and more prone to sensitivity and decay. If you have periodontitis, your dentist can recommend treatment options, including antibiotics, deep cleanings, and/or gum surgery.

• Acidic Erosion

Acids can erode tooth enamel, exposing the dentin underneath. Acidic foods should be enjoyed in moderation and eaten with meals. Sodas and energy drinks should be limited. Medical conditions such as acid reflux can be very damaging to enamel, especially on the back of the teeth, and should be treated by your physician. Enamel won’t grow back, but if you have suffered significant enamel erosion, your dentist might suggest fillings, crowns, bonding, or veneers.

• Abrasive Erosion

Aggressive brushing and hard-bristled brushes can be so abrasive that they cause enamel erosion and gum recession. Use a soft bristled or electric toothbrush, and brush thoroughly but gently. Your dentist can recommend better brushing techniques and toothpastes which reduce sensitivity.

• Tooth Grinding

Repetitive nightly grinding can put so much pressure on the teeth that the outer layer of enamel is worn away. Tiny cracks and fractures develop. Pulp inflammation can occur. A custom-fitted nightguard is a common treatment used to redistribute grinding pressures.

• Malocclusion

Too much pressure on a tooth caused by an unbalanced bite can lead to worn or cracked teeth or pulp inflammation. Orthodontic treatment is often recommended to create a healthy, balanced bite.

Tooth sensitivity shouldn’t be ignored. Any unpleasant or painful sensation which persists should be evaluated by your dentist to determine the cause of your sensitivity and to create a treatment plan for a pain-free smile.