Tooth sensitive to cold: causes, relief, and when to worry

What’s probably going on

Under your enamel is a softer layer called dentin. It’s full of tiny channels that lead toward the nerve. When enamel wears thin or gums pull back, those channels are exposed, and cold can reach the nerve.

The most useful clue is how long the pain lasts.

• A brief zing that fades in a few seconds. On its own, this generally doesn’t signal a serious problem. It often means exposed dentin or a small cavity.
• Pain that lingers 30 seconds or more. This is more urgent. It can mean deep decay or an injury has damaged the nerve for good, and the tooth may need a root canal to save it. See a dentist as soon as you can.

Common causes:

• Worn enamel. Acidic foods and drinks, brushing too hard, and grinding can all wear enamel down.
• Gums pulling back (recession). When gums pull back, the sensitive root surface shows. Brushing too hard and gum disease can both play a part.
• A cavity. Decay opens a path toward the nerve. Sensitivity to cold or sweets that is getting worse needs a check.
• A cracked tooth or worn filling. A crack, a chip or a worn filling can leave a tooth sensitive. See cracked tooth.
• Recent whitening or dental work. Whitening products can make teeth sensitive. A new filling or other treatment can inflame the nerve for a while. If it hasn’t settled within a week or two, or it’s getting worse, have it checked.
• Grinding or clenching. Grinding is another common cause of sensitive teeth. See grinding.

If the cold pain comes with pain when you chew, see tooth hurts when biting.

What to do tonight

A brief zing from cold can usually wait for a regular appointment. These steps can make it more comfortable in the meantime.

1. Switch to a sensitivity toothpaste. Brush with it at least twice a day, and make sure you brush the sensitive spots.
2. Spit, don’t rinse. After brushing, spit out the extra toothpaste but skip the water rinse, so more of it stays on your teeth.
3. Give it a few weeks. These toothpastes usually take several brushings before sensitivity eases, so one night won’t tell you much.
4. Try a dab before bed. You can put a little on the sore spot at bedtime.
5. Brush gently. Use a soft or extra-soft brush and brush up and down, not side to side.
6. Go easy on triggers for now. Ice water, very cold food, and acidic foods and drinks such as citrus can set it off.

If the pain lingers after cold, or the tooth throbs at night, don’t wait on toothpaste. See toothache at night and book a dentist.

What not to do

• Don’t scrub harder. Brushing hard wears enamel and makes gums pull back, which makes sensitivity worse.
• Don’t use a sensitivity toothpaste for months to cover a problem. A leading brand’s label says to stop and ask a dentist if sensitivity still persists after four weeks of use, or if it gets worse.
• Don’t keep whitening through the pain. Pause and ask your dentist before carrying on.

How a dentist fixes it, and what it costs

A dentist looks for the cause: a cavity, a crack, a worn filling, gum recession or grinding. The fix depends on what they find.

• Worn enamel or mild sensitivity. A fluoride gel or varnish applied in the office can strengthen enamel and reduce the sensation.
• Exposed dentin or small flaws. Bonding or a sealant can cover the sensitive area.
• Gum recession. A gum graft can cover and protect a root that has lost its gum tissue.
• A cavity or worn filling. These are repaired, often with bonding or a new filling.
• Lingering pain from a damaged nerve. This usually needs a root canal.

The price depends on which of these you need, the tooth, where you live and your coverage. Ask for a written estimate before any work starts.

If you don’t have dental insurance, a dental savings plan (a discount membership, not insurance) can cut the price at participating dentists.

How to keep it from coming back

Most sensitivity comes from slow wear, so everyday habits make the biggest difference.

• Brush twice a day with a soft-bristled brush and gentle strokes.
• Keep using the sensitivity toothpaste if it helps, and a fluoride toothpaste either way.
• Floss once a day to help keep gums healthy.
• Cut back on acidic foods and drinks.
• If you grind your teeth, ask your dentist about a mouth guard.
• Get regular checkups, so cavities and worn fillings are fixed early.

For help choosing a brush, see the best electric toothbrush.