What Causes Tooth Sensitivity?

The mechanism

Beneath enamel lies dentine, which is threaded with microscopic tubules containing fluid. When dentine is exposed — at the gumline, on a worn biting surface, or around a restoration — temperature changes, sweetness and touch move that fluid, and the movement is registered as a short, sharp sensation.

This is why classic sensitivity is brief and stops when the stimulus is removed.

Common causes of exposed dentine

Several everyday processes uncover dentine gradually.

• Gum recession, exposing root surfaces that have no enamel covering
• Abrasion from forceful brushing or a hard-bristled brush
• Erosion from acidic drinks, frequent citrus, or reflux
• Grinding and clenching, which wear through enamel over time
• Recent dental treatment, which usually settles within weeks
• Whitening treatment, typically temporary

When sensitivity means something else

Certain patterns point away from simple dentine sensitivity and towards a problem that needs diagnosis: pain that lingers for many seconds after cold, pain that wakes you at night, pain on biting down or on release, sensitivity confined to one tooth that is worsening, or any accompanying swelling.

These can indicate decay reaching the pulp, a cracked tooth, a failing restoration or infection — and none of them are solved by a desensitising toothpaste.

What generally helps

For genuine dentine sensitivity, toothpastes containing potassium nitrate or stannous fluoride help many people, but they work cumulatively — several weeks of consistent use, and smearing a little on the sensitive area at night rather than rinsing immediately.

Alongside that: a soft-bristled brush with light pressure, waiting rather than brushing immediately after acidic food or drink, reducing the frequency of acidic exposures, and treating grinding if present. In-office options include fluoride varnish, bonding agents and, where recession is significant, gum grafting.