Key points
- Exposed dentin lets hot and cold reach the nerve
- Desensitising toothpaste usually needs several uses before it works
- Decay, cracks, worn fillings and receding gums can all cause it
- A dentist can seal, bond or protect the sensitive area
Why teeth become sensitive
Under the hard enamel is a softer layer called dentin, full of tiny channels that lead to the nerve. When enamel wears thin, or gums recede and expose the root, those channels let heat, cold and acid reach the nerve. The American Dental Association lists these common causes:
- Tooth decay
- Cracked or broken teeth
- Worn fillings
- Gum disease
- Worn enamel
- Exposed roots where the gums have receded
Treatments for sensitive teeth
The right treatment depends on the cause:
- Desensitising toothpaste, which blocks sensation from reaching the nerve. It usually needs several applications before you notice a difference
- Fluoride gel applied at the clinic to strengthen enamel
- A filling, crown or bonding to fix decay or a flaw that is causing it
- A gum graft to cover an exposed root, where gum has been lost
- Rarely, a root canal for severe sensitivity that nothing else resolves
What you can do at home
Good daily care is the best prevention: brush twice a day with a soft brush and fluoride toothpaste, and don't scrub hard, which wears enamel and gums. If you use a desensitising toothpaste, give it a couple of weeks of regular use.
When to see a dentist
See a dentist if you have
- Sensitivity that doesn't improve after a few weeks of desensitising toothpaste
- Pain that lingers after hot or cold food
- Pain when you bite, which can mean a crack
- Sensitivity with bleeding or receding gums
How Dental Plus can help
At Dental Plus we find the cause first, with an examination and an X-ray if needed, then treat that, rather than just masking the pain. Sensitivity after a new filling is common for a week or two; see our fillings guide for what is normal.
Common questions
How long does sensitive toothpaste take to work?
It usually needs several applications, often a week or two of regular use, before the sensitivity eases.
Is sensitivity a sign of decay?
It can be. Decay, a cracked tooth or a worn filling can all cause it, which is why sensitivity that lasts should be checked.
Why are my teeth sensitive after whitening?
Some sensitivity is a common, usually temporary, side effect of whitening. Tell your dentist if it does not settle.
Can sensitive teeth be fixed permanently?
Often, once the cause is treated: a filling for decay, bonding over an exposed area, or treatment for gum disease.
Sources
Checked on 16 October 2026. This guide is general information, not a diagnosis. If you are worried, see a dentist.