Sensitive teeth hurt briefly when exposed to cold, hot, sweet or sour things, or to air, because the softer layer under the enamel (dentine) has become exposed. Often it can be eased with a desensitising toothpaste and gentler brushing, but sensitivity can also signal a cavity, a crack or gum disease, so lasting or worsening pain should be examined.
What is happening inside the tooth
A tooth has a hard outer layer of enamel on the crown. Under the gum, the root is covered by a thinner layer called cementum. Beneath both lies dentine, which is full of microscopic channels that lead to the nerve. When dentine is exposed, hot, cold, sweet, acidic foods and even air can move the fluid in those channels and trigger a short, sharp twinge. This is dentine hypersensitivity.
Sensitivity that stops within seconds of removing the trigger is typical for this. Pain that lingers, throbs or arrives on its own points to something else.
Common causes
Worn enamel. Enamel wears from brushing too hard, a hard brush, or a gritty toothpaste. It also wears from acid. Acid comes from fizzy drinks, citrus juice, pickles, and from stomach acid in reflux or repeated vomiting.
Gum recession. When gums pull back, the root surface is exposed. It has no enamel, so it is far more sensitive. Recession is caused by gum disease, hard brushing, and sometimes by teeth that sit forward in the jaw.
Tooth decay. A cavity can reach the dentine and cause sensitivity, especially to sweet things. This is one reason not to assume sensitivity is harmless.
A cracked or chipped tooth. A crack can cause sharp pain on biting and release, or to cold.
Worn, leaking or broken fillings or crowns with gaps at the edges.
Grinding or clenching. Over time, grinding wears enamel and can crack teeth.
Recent dental treatment. Teeth may be sensitive for a few days to a few weeks after a filling, scaling or whitening. This usually settles. See teeth whitening aftercare.
Gum disease treatment. After deep cleaning, root surfaces may be briefly more sensitive.
What helps at home
- Use a desensitising toothpaste (those containing potassium nitrate, stannous fluoride or similar). Brush with it twice a day and let it work for several weeks, as it builds up gradually. You can also dab a little on the sensitive area before bed.
- Switch to a soft brush and use light pressure and small circles. If you can see bristles bend flat, you are pressing too hard.
- Do not brush straight after acidic food or drink. Wait about 30 minutes, since acid softens enamel temporarily.
- Cut back on acidic and sugary drinks. Drink them with meals, and use a straw where you can.
- Use fluoride toothpaste and, if advised, a fluoride mouthwash.
- Avoid whitening toothpastes and charcoal powders or home remedies such as lemon or baking soda scrubs, which are abrasive or acidic.
Warm water rinses rather than very cold ones can make daily life easier while the teeth settle.
What a dentist can do
A dentist will try to find the cause before treating the symptom. That may involve an examination, an X-ray, and tests with a cold stimulus or gentle bite test. Depending on the cause, treatment may include:
- fluoride varnish or desensitising agents applied to exposed areas
- sealing or bonding of exposed root surfaces
- replacing a worn or leaking filling
- treating decay
- a night guard if you grind
- treating gum disease, and in some cases gum grafting for severe recession
- root canal treatment if the nerve of one tooth is inflamed beyond recovery
See the sensitive teeth page for a closer look.
When it is not just sensitivity
Pain that hangs on for minutes after hot or cold, throbs, or wakes you at night suggests the nerve is inflamed or infected. A single tooth that hurts when you bite, with swelling or a pimple on the gum, needs to be checked soon. Also watch for sensitivity that is getting worse over weeks, or that affects only one tooth. Sensitivity in many teeth at once is more often from enamel wear or recession.
Preventing it
- Brush twice a day with a soft brush and a fluoride toothpaste, with gentle pressure.
- Clean between teeth daily to protect the gums.
- Keep acidic drinks to mealtimes.
- Treat gum disease early.
- Get a night guard if you grind.
- Have check-ups so small cavities and worn fillings are found early. See how often you should see a dentist.
Most sensitivity can be controlled, but it is worth knowing the cause. Easing the pain with toothpaste and leaving a cavity underneath is the most common reason a simple problem becomes a larger one.
When to see a dentist
- Pain that lingers for minutes after hot or cold
- Pain that wakes you at night or throbs on its own
- Sharp pain when you bite and release
- Sensitivity in one tooth only, or getting steadily worse
- Swelling, a pimple on the gum, or a chipped or cracked tooth
Related treatment: General dentistry: check-ups, cleaning and fillings →