Tooth sensitive to heat: why it matters and what to do

What’s probably going on

Inside every tooth is the pulp, the soft center that holds the nerve and blood vessels. When the pulp is irritated or inflamed, dentists call it pulpitis. Heat is one of the things an inflamed pulp reacts to.

That’s why heat pain deserves a closer look than cold pain. Cleveland Clinic lists “no sensitivity to heat” as a sign of early, fixable pulpitis. Heat, cold or sweets pain that lasts more than a few seconds points to the kind that won’t heal.

Heat alone doesn’t settle it, though. The American Association of Endodontists says a brief twinge from hot or cold is generally not serious. The most useful clue is how long the pain lasts.

• A brief twinge that fades in a few seconds. This generally isn’t a sign of anything serious, unless it keeps happening for a long time. It can come from a small cavity, a loose filling or gums that have pulled back.
• Pain that lingers 30 seconds or more after the heat is gone. This often means the pulp has been damaged by deep decay or an injury and can’t heal on its own. The tooth usually needs a root canal to save it.
• Pain that starts on its own, or throbs. A throbbing or aching pain is another sign of an inflamed pulp that isn’t healing. See throbbing tooth pain.

Common causes of a heat-sensitive tooth:

• A deep cavity. Decay that reaches close to the nerve lets bacteria in and inflames the pulp.
• A cracked tooth. A crack can let bacteria reach the pulp and inflame it. Cracked teeth often hurt when you bite, too. See cracked tooth.
• Recent or leaky dental work. A filling that isn’t sealed well can let bacteria reach the pulp. Some sensitivity right after treatment is normal. See tooth pain after a filling.
• Worn enamel. Grinding and hard brushing can wear enamel down and leave the inner layer exposed.

If your tooth reacts mostly to cold and the pain fades fast, see tooth sensitive to cold instead.

When the pain suddenly stops

If a tooth that hurt with heat for days suddenly stops hurting, don’t take it as good news. When the nerve dies, the tooth may stop reacting to heat, cold or sweets altogether. The infection can keep going without pain, and can turn into an abscess. A dentist should still check it.

What to do tonight

Lingering heat pain usually can’t be fixed at home. These steps can make the wait more comfortable until you can get in.

1. Call a dentist and describe the pain. Say it hurts with heat and how long it lasts. That detail helps them decide how soon to see you.
2. Avoid hot food and drinks. Let coffee, tea and soup cool to lukewarm, and chew on the other side.
3. Take an over-the-counter pain reliever as the label directs. For adults and teens 12 and up, anti-inflammatories such as ibuprofen or naproxen, alone or with acetaminophen, are a usual first choice. Ask a pharmacist first if you take other medicines, are pregnant, or have stomach, kidney or bleeding problems.
4. Keep the area clean. Brush gently and floss around the tooth, in case food is packed against it.
5. Sleep with your head raised. An extra pillow can ease the pressure that makes tooth pain worse lying down. See how to sleep with a toothache.

For more ways to get through the night, see what to do for a toothache right now.

What not to do

• Don’t count on sensitivity toothpaste. It helps surface sensitivity. It won’t calm an inflamed nerve, and it can delay the visit you need.
• Don’t put aspirin on the tooth or gum. It burns the tissue.
• Don’t take leftover antibiotics. They don’t fix an inflamed nerve, and only a dentist or doctor should decide whether you need them.
• Don’t wait because the pain comes and goes. An inflamed pulp can die quietly and turn into an infection.

How a dentist fixes it, and what it costs

A dentist will look at the tooth, take an X-ray, and usually test how it reacts to temperature. The fix depends on how far the inflammation has gone.

• Early, fixable inflammation. The dentist removes any decay and seals the tooth with a filling. The pulp can then settle down.
• Damaged pulp (lingering heat pain). A root canal removes the inflamed pulp, cleans the inside of the root, and fills and seals it. A back tooth usually needs a crown afterward.
• A tooth that can’t be saved. It’s taken out, and the gap is often filled with an implant or bridge.

Root canals on front teeth usually cost less than on molars, which have more canals and are harder to reach. The complexity of the case and where you live also change the price. Taking the tooth out may look cheaper, but replacing it with an implant or bridge usually costs more than the root canal would have.

Ask for a written estimate before any work starts. For price ranges, see root canal cost and crown cost, or try the dental cost estimator. 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 heat-sensitive teeth start as a cavity or crack that went unnoticed for months.

• Brush twice a day with a fluoride toothpaste, gently, with a soft brush.
• Clean between your teeth once a day.
• Cut back on sipping sugary or acidic drinks through the day.
• Get regular checkups, so small cavities and worn fillings are fixed before they reach the nerve.
• If you grind or clench, ask about a night guard. See grinding.
• Don’t ignore a tooth that has started reacting to temperature. Early treatment is often a filling; late treatment is often a root canal.

For help with the first habit, see the best electric toothbrush.