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A cold drink hits and a tooth gives a short, sharp jolt that disappears almost immediately. That is classic dentine sensitivity, and it is extremely common.
Underneath enamel is dentine, and dentine is threaded with microscopic tubules running towards the nerve. Enamel seals them. When enamel is worn through, or the gum recedes and exposes root surface which never had enamel in the first place, those tubules open — and cold, sweet or touch travels straight down them.
Why the dentine got exposed
Brushing too hard, which abrades enamel at the neck of the tooth and makes gums recede. Usually it works alongside acid rather than on its own, and it is the most preventable part of the picture.
Acid erosion, from fizzy drinks, citrus, wine or reflux, dissolving enamel from the surface.
Gum recession, from gum disease, from age, or from brushing.
Grinding or clenching, which wears the biting surfaces flat.
Recent treatment. A new filling, a scale and polish, or whitening commonly causes sensitivity for days to a few weeks. This settles.
A crack, which tends to be one specific tooth and often hurts on releasing a bite rather than on pressing.
The distinction that matters
| Short and sharp | Lingering | |
|---|---|---|
| Lasts | A second or two | Minutes after the stimulus has gone |
| Triggered by | Cold, sweet, air, touch | Cold and increasingly heat |
| Usually means | Exposed dentine | Pulp inflammation |
| What to do | Manage it, find the cause | Get it examined |
Pain that outlasts the trigger, builds, throbs, or wakes you at night is not ordinary sensitivity. It suggests the nerve inside the tooth is inflamed, which is a different problem with a different treatment. Heat sensitivity specifically, and pain relieved by holding cold water on the tooth, is a pattern worth reporting promptly.
What helps
Desensitising toothpaste, used properly. The two common active ingredients are potassium salts, thought to settle the nerve, and stannous fluoride, thought to block the tubules. Trials of both are small and mixed, so treat it as worth trying rather than guaranteed. Use it as your normal paste twice a day, and additionally rub a little onto the sensitive spot with a fingertip at night and do not rinse. Give it two to four weeks.
Stop rinsing after brushing. Rinsing washes off the fluoride you have just applied, which matters more here than almost anywhere else.
Lighten your brushing and use a soft brush. If your bristles splay within weeks, that is your answer.
Leave an hour after anything acidic before brushing. Enamel is temporarily softened and brushing straight away removes it.
A night guard, if you grind.
What a dentist can add
Fluoride varnish on the sensitive areas, sealants or bonding over exposed root surfaces, and treating whatever is causing it. Where recession is severe, a gum graft is occasionally appropriate.
Sensitivity is not a disease in itself. It is the surface telling you something has worn through, and that something is usually still happening.
