Why do teeth feel sensitive?
The outside of a tooth is covered by hard enamel, and the dentin inside it has countless very fine tubes leading toward the nerve. When the enamel wears down or the gums recede and the dentin is exposed, a cold stimulus moves the fluid inside these tubes and the signal reaches the nerve, causing a sharp, tingling sensitivity. This is called dentin hypersensitivity, commonly known as sensitive teeth.
| Cause | What it looks like |
|---|---|
| Gum recession | The tooth looks longer and the yellowish root area is visible |
| Wear at the tooth neck | A V-shaped notch at the gumline; a habit of brushing hard side to side |
| Acid erosion | Frequently drinking soda, fruit juice, or vinegar; the surface is worn smooth |
| Teeth grinding and clenching | The biting surfaces are worn flat; the jaw feels stiff in the morning |
| Cavity or cracked tooth | Sensitivity in only one tooth; a sharp twinge when biting |
| Temporary sensitivity after treatment | A few days to a few weeks after scaling, whitening, or a new filling |
Do I need treatment if my teeth are only briefly sensitive to cold water?
If it is brief and goes away right away, it is not urgent, but it is a good idea to find the cause. A worn notch or acid erosion gets gradually deeper if left alone. The first thing I ask is how long the sensitivity lingers.
| Pattern of sensitivity | What I suspect | What to do |
|---|---|---|
| Sensitive to cold for 1–2 seconds and goes away right away | Dentin hypersensitivity | Desensitizing toothpaste, changing habits, fluoride application |
| A sharp twinge in one tooth when biting | Cavity or cracked tooth | See a dentist |
| Lingers for more than 10 seconds after the stimulus, or hurts with hot things too | Possible nerve inflammation | See a dentist soon |
| Throbbing even at rest, or at night | Progressing nerve inflammation | See a dentist soon; root canal treatment may be needed |
How to tell whether a throbbing molar is a cavity is covered in If my molar throbs, is it a cavity?
Does desensitizing toothpaste work?
It works for dentin hypersensitivity, but it takes time. Potassium nitrate reduces the nerve’s response, and ingredients such as stannous fluoride or arginine block the openings of the exposed tubes. You usually need to use it every day for 2–4 weeks or more to notice a difference, and the sensitivity can come back if you stop.
Applying a little toothpaste to the sensitive area, leaving it for a while, and then spitting it out also helps. If nothing changes after more than a month of use, it is likely not the kind of sensitivity that toothpaste can solve.
How do dentists treat sensitive teeth?
Depending on the cause, we start with the lightest option.
| Treatment | For | Cost at Wonjin Dental |
|---|---|---|
| Fluoride or medication application | Sensitivity over a wide area | Fluoride application ₩30,000 |
| Composite filling at the tooth neck | A V-shaped notch | Cervical composite filling ₩150,000 |
| GI filling | Notch at the tooth neck; an insurance-covered material | Korean National Health Insurance |
| Night guard for grinding | Teeth grinding and clenching | ₩500,000 |
| Cavity treatment or root canal treatment | Cavity or nerve inflammation | Depends on the extent of treatment |
Prices are as of September 2026, and the full list is on all treatment fees. The options when the gums have receded and exposed the root are summarized in Can receded gums grow back? Root canal treatment is not the first treatment for sensitive teeth but the last option when other methods do not work.
What should I change to prevent sensitive teeth?
- Brush at the gumline with a soft toothbrush using short, vibrating strokes, and do not scrub hard side to side.
- Drink soda and fruit juice quickly through a straw and rinse with water. Right after drinking, wait about 30 minutes before brushing.
- Avoid using toothpaste with a lot of abrasives, such as whitening toothpaste, every day.
- If your jaw feels stiff when you wake up, consider that you may be grinding your teeth.
How we handle it at Wonjin Dental
When you come in with sensitive teeth, I first check how many seconds the sensitivity lingers and which tooth it starts from, and I check the nerve’s condition with a cold stimulus and tapping. If it is dentin hypersensitivity, I recommend toothpaste, changing habits, and fluoride application first, and if the notch is deep, I fill it with composite or GI. I recommend root canal treatment only when nerve inflammation is confirmed.
Frequently asked questions
My teeth are sensitive after scaling. Is that normal?
It is common sensitivity that happens because surfaces that were covered by tartar are now exposed, and it usually eases within a few days to 2 weeks. Using desensitizing toothpaste in the meantime helps. If it is still the same after 2 weeks, have it checked again.
Is sensitivity after whitening different from regular tooth sensitivity?
It is sensitivity caused by the whitening agent temporarily making the nerve more sensitive, and it mostly goes away within a day or two. More details are in Does whitening make teeth sensitive?
Are my teeth sensitive because of my age?
As you get older, the gums recede and teeth wear down, so sensitivity becomes more common, but age itself is not the cause. Most causes can be changed, such as brushing habits, acidic drinks, and teeth grinding, so it is worth having them checked.
