How does desensitizing toothpaste work?

In healthy teeth, a layer of enamel protects the crowns of your teeth -- the part above the gum line. Under the gum line a layer called cementum protects the tooth root. Underneath both the enamel and the cementum is dentin. When dentin loses its protective covering of enamel or cementum these tubules allow heat and cold or acidic or sticky foods to reach the nerves and cells inside the tooth. Dentin may also be exposed when gums recede. The result for both can be hypersensitivity.

One way to treat sensitive teeth is by using desensitizing toothpaste, which contains compounds that help block transmission of sensation from the tooth surface to the nerve. It usually requires several applications before the sensitivity is reduced.

There are many reasons your teeth may be sensitive. Proper oral hygiene is the key to preventing sensitive-tooth pain. Ask your dentist if you have any questions about your daily oral hygiene routine or concerns about tooth sensitivity.
Todd A. Welch, DMD
Potassium nitrate decreases tooth sensitivity by entering into the dental tubules and making its way to the nerves of the dental pulp. These potassium ions find their way tot he pulp where they block the transmission of pain to the brain.  While hot and cold would still cause the nerves to send a pain signal to the brain, the potassium ion interrupts the pain signal so that you don't feel anything.

An added benefit of potassium nitrate is that it can build up in the dentin tubules. By continuing to brush with sensitivity toothpaste, you can provide your dentin tubules with a large supply of potassium nitrate which will give you lasting relief from sensitivity.

Strontium chloride works by blocking the dentin tubules. The dentin tubules are very tiny holes that go to the dental pulp. Strontium chloride simply covers up these holes. Normally, the tubules are covered up by cementum on the tooth root or enamel on the tooth crown. Strontium chloride simply returns the tubules to their natural "covered up" state.

If the dentin tubules are open, then it is easy for sensations to be transferred to the nerves in the dental pulp. By closing the tubules with strontium chloride, you can eliminate tooth sensitivity by stopping the nerves of the dental pulp from receiving any painful stimulation.
Desensitizing toothpastes can help people whose teeth are sensitive to heat or cold. These toothpastes contain ingredients such as strontium chloride and potassium nitrate that help block the transmission of pain signals from the surface of your tooth to the nerve inside. They do this by stopping up the tiny tubes in the dentin of your teeth. The dentin is the layer of tissue beneath the hard enamel. Desensitizing toothpastes usually take a month of regular use to decrease pain.
Jonathan B. Levine, DMD
Sixty percent of the American population has sensitivity issues with their teeth and can benefit from desensitizing toothpaste. When the tooth's nerve is exposed, it becomes sensitive to different conditions, like sweetness and temperature. This recession can occur from either environmental factors or heredity. The recession prompts those tiny dentinal tubules to transmit an impulse to the nerve. Desensitizing toothpastes contain active ingredients, such as potassium nitrate, which seals up the tubules, preventing fluid to flow there, which is what sets off the sensitivity. Potassium nitrate has proven itself to be the most effective desensitizing agent when receding gums expose root. In order for a toothpaste to be effective, however, it must contain a concentration of about 5percent potassium nitrate, or any of the other active ingredients. An example is Sensodyne F.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.