A cut finger tells you exactly where it hurts. A tooth often does not. Pain from the nerve inside a tooth tends to feel spread out, and it can seem to come from the top jaw when the problem is in the bottom one, or from the ear rather than a molar. That is normal, and a dentist can usually track down the source with a few comparisons between teeth and an X-ray.
The tooth's nerve gives a poor sense of location
The pulp at the centre of each tooth contains nerves and blood vessels. In a 2000 review in the Journal of Endodontics, Bender described two kinds of pain fibres in the pulp: fast fibres that produce a quick, sharp pain, and slow fibres that produce a dull, lingering ache. The slow, dull kind is typical of an inflamed pulp, and it is the kind that is hardest to place. The pulp has little ability to report position, so the brain gets a message that something hurts on that side without a precise address.
The ligament that holds each root in the bone works differently. It is rich in nerve endings that sense pressure and position. While a problem stays inside the pulp, the pain is vague. Once inflammation or infection spreads to the tissue around the root tip, the tooth often becomes sore to bite on or tap, and many people can then point to it.
Where referred tooth pain tends to show up
Pain felt away from its true source is called referred pain. With teeth, common patterns include:
- a lower back tooth that feels like an upper tooth, or the other way around
- a back tooth felt in the ear, temple or jaw joint, which our article on whether a tooth can cause ear pain explains
- a front tooth felt around the nose or under the eye.
Pain from a single tooth usually stays on one side of the face. An ache that moves from side to side, or involves many teeth at once, points more toward the jaw muscles, the sinuses or another cause.
Patterns worth noting at home
Keeping a few notes on what sets the pain off helps narrow things down before you are examined. A short, sharp twinge with cold that fades within seconds often goes with exposed dentine, a leaking filling or early decay. Pain from hot or cold that lingers well after the hot or cold is gone is more suggestive of a pulp that is badly inflamed and may not recover. A sharp pain when biting on something small, especially as you release, is a classic sign of a cracked tooth or cracked filling, which our guide to pain when biting down covers.
A tooth that feels high or is sore to tap suggests inflammation around the root tip. A throbbing ache that wakes you at night tends to mean a seriously inflamed or dying nerve. An ache across several upper back teeth that worsens when you bend forward, with a blocked nose, may be the sinuses rather than a tooth, as explained in our article on sinus toothache. A dull ache on waking with tired jaw muscles often points to clenching or grinding.
Testing one tooth against its neighbours
Getting the right tooth matters more than speed, because treating a healthy tooth does not fix the pain. A dentist starts with questions about when the pain began, what triggers it, how long it lasts and whether it wakes you, then examines each tooth on that side for decay, broken fillings, cracks, gum swelling or a small gum boil.
Cold testing is one of the most useful steps. A very cold pellet is touched to several teeth, including healthy ones for comparison. A tooth that reacts much more strongly, or keeps hurting after the cold is removed, becomes a suspect, while a tooth that feels nothing may have a nerve that has died. In a 2018 systematic review in the Journal of Endodontics, Mainkar and Kim found cold testing had a pooled accuracy of about 0.84 for telling whether a pulp is alive, which is good but not perfect, so it is used together with other checks.
Biting on a small instrument, one cusp at a time, can bring on the pain of a crack, and tapping gently on each tooth shows which is tender at the root. X-rays show decay between teeth, deep fillings near the nerve and changes in the bone around the root tip. Our guide to dental X-ray types explains what each view shows, and a 3D scan may be suggested if the answer is still unclear. When it is hard to tell even whether the pain is upper or lower, numbing one jaw first can help: if the pain stops when the upper teeth are numb, the cause is likely there.
Sometimes the answer takes a little time
Occasionally every test is borderline. The dentist may then suggest pain relief, place a protective dressing on a suspect filling, or arrange a review in a week or two. Pulp problems often become clearer with time, and a short wait is safer than treating a tooth that turns out to be healthy. Cracks are a frequent cause of this kind of hard-to-place pain, and our article on cracked tooth syndrome explains why they can be difficult to see.
If no tooth is to blame, the cause may be the jaw muscles, the jaw joint, the sinuses or a nerve condition, and your dentist can refer you to a doctor or an appropriate specialist.
Looking after it until your appointment
- Take over-the-counter pain relief as directed on the packet, if it is safe for you. Our article on ibuprofen and paracetamol for tooth pain compares the two.
- Chew on the other side and avoid very hot, very cold or hard foods.
- Note what brings the pain on and how long it lasts.
- Do not hold aspirin against the gum, as it can burn the tissue.
Pain that keeps you awake, a tooth that feels high, or swelling of the gum or face should be seen the same day or the next. Our emergency dentist page explains how urgent appointments work, and routine visits are covered on our general dentistry page.
Signs that need a hospital, not a dental chair
Go to a hospital emergency department or call 000 if you have facial swelling spreading toward the eye or down the neck, difficulty swallowing or breathing, or a fever with a swollen face. These can signal a spreading infection. Our guide on when to go to hospital for a dental problem has more detail.
Jaw pain that comes with chest pain, breathlessness or sweating should also be treated as a medical emergency, because heart pain can be felt in the lower jaw.
Two more questions
The pain has stopped by itself. Is that good news?
Sometimes an irritated nerve settles down. Sometimes the nerve dies, and the pain eases for a while before an infection develops at the root tip. A tooth that hurt badly and then went quiet is worth checking.
Will I need root canal treatment?
Not necessarily. A pulp that can still recover may only need a filling or a crack treated. A pulp that is irreversibly inflamed or has died usually needs root canal treatment or removal of the tooth.
If you have an ache you cannot place, the team at Lumi Dental can run the tests and explain what they find before any treatment is decided. Current appointment offers are listed on our deals page.
