Why Is My Tooth So Sensitive to Cold?

My upper right molar tooth has a large filling in it. The tooth is so sensitive to cold and air. Last Wednesday, my dentist used a tool to blow air on the tooth to see if it hurt or was sensitive; it was. Afterward, my dentist applied a desensitizing gel to the tooth and said the sensitivity should decrease. Is that it—five minutes of blowing air on a tooth without figuring out what’s wrong? What could be causing the sensitivity? Kyle from AZ

 

Kyle,

Sometimes sensitivity in a tooth is easy to diagnose. At other times, it is more complicated. Your dentist performed a standard test to determine the areas of discomfort.

Air Test for Tooth Sensitivity

A dentist might blow air on a tooth to determine if any portion is unprotected and sensitive. A desensitizing bonding agent will coat and protect the tooth.

What Causes a Tooth to Be Sensitive to Cold?

The cause of cold sensitivity in a tooth depends on the pain you are feeling and the tooth’s condition.

Type of pain

1. Pain that goes away quickly – The tooth pulp (the living tissue inside the tooth) or nerves are irritated but could heal.
2. Lingering pain – Tooth pulp or nerve irritation will not heal. Your dentist can complete a root canal treatment to remove the infected pulp and nerves.
3. Established filling – Any space between the edges of a dental filling and your tooth allows bacteria inside. Tooth decay beneath the filling will cause pain and sensitivity to cold.

Tooth condition

1. New filling – Sensitivity immediately after getting a new silver or composite filling is normal. However, if sensitivity begins later, bacteria from the previously decayed tooth can infect the pulp (the living tissue inside) and irritate your tooth. You may need root canal treatment to resolve it.
2. Wisdom tooth extraction – Sometimes, the adjacent tooth’s root is exposed and becomes sensitive during wisdom tooth extraction. Toothpaste for sensitive teeth often resolves the issue. According to the American Dental Association, it takes several applications before desensitizing toothpaste relieves symptoms. Otherwise, your dentist can apply a desensitizing agent to the tooth.
3. Tooth decay – Decay or infection can irritate tooth pulp, causing sensitivity to cold or heat.
4. Fracture – A fracture can irritate tooth nerves and increase sensitivity to cold. If you leave the tooth untreated, pulp damage can become irreversible, requiring root canal treatment and a dental crown. A severe fracture can make the tooth unsavable, requiring a dental implant.
5. Gum recession – If your gums pull away from your teeth, exposed tooth roots can be sensitive to cold or heat. Desensitizing toothpaste may help, or your dentist may recommend a gum grafting procedure to cover the exposed roots and reduce sensitivity.
6. Worn tooth enamel – Dentin (the layer beneath the enamel) is exposed when tooth enamel wears down. Without protection from tooth enamel, heat, and cold can enter the dentin and stimulate tooth nerves. Dentin contains small tubes that lead to tooth nerves.

You can ask your dentist to identify the cause of your tooth sensitivity or see a skilled cosmetic dentist for a second opinion.

Beverly Hills accredited fellow of cosmetic dentistry Dr. Brian LeSage sponsors this post.