Seven signs a tooth may need root canal treatment

Most people picture root canal treatment as something that follows unbearable toothache. Sometimes it does. Just as often, though, the warning signs are quieter — a sensitivity that lasts a little too long, a tooth that feels different when you bite, a small spot on the gum that comes and goes. Knowing the signs means problems are caught while the tooth is still straightforward to save.

1. Pain that lingers after hot or cold

A brief twinge from ice cream or a cold drink is common and usually harmless. Pain that builds and then lingers for a minute or more after the cold has gone, or pain triggered by a hot drink, suggests the pulp inside the tooth is inflamed beyond recovery. This is the single most reliable early sign.

2. Pain that comes on by itself

Toothache that starts without any trigger — while you are reading, driving or lying in bed — is a symptom of an inflamed or dying pulp. Pain that wakes you at night, or throbs in time with your pulse, belongs in the same group and should be assessed within days rather than weeks.

3. Pain on biting or tapping

When a tooth is tender to bite on, or hurts when you tap it with a fingernail, the inflammation has usually spread beyond the root tip into the bone. The same symptom can be caused by a crack, which is why a proper examination matters before any treatment is planned.

4. Swelling or a gum boil

A swelling in the gum beside a tooth, a puffy cheek or a small pimple on the gum that releases a bad taste all indicate infection draining from a dead tooth. Antibiotics may calm the swelling for a while, but they cannot reach the bacteria inside the tooth; the infection returns until the canals are treated.

5. A tooth that has darkened

A front tooth that slowly turns grey or brown, often years after a knock, has usually lost its blood supply. There may be no pain at all, but the dead tissue inside the tooth can become infected at any time, and treatment is recommended before that happens.

6. A deep filling, crown or recent repair that still hurts

Some sensitivity after a large filling is normal and settles over a few weeks. Pain that persists, gets worse or starts weeks after the work was done suggests the pulp did not recover from the decay or the drilling and now needs treatment.

7. No symptoms at all — but a problem on the X-ray

Infections can smoulder silently for years. A dark area around a root tip on a routine X-ray at your check-up is a common way for them to be discovered. The tooth may feel perfectly normal; it still needs treatment, because the infection is slowly destroying bone.

When it is not the nerve

Gum disease, sinus congestion, jaw joint problems, a cracked cusp and even referred pain from a neighbouring tooth can all mimic these signs. That is why an endodontic consultation starts with testing — cold, heat, bite and percussion tests and the right X-rays — rather than with treatment. Our page on tooth pain diagnosis explains what happens.

What to do next

If you recognise one or more of these signs, arrange an assessment. Early treatment is simpler, more comfortable and more likely to keep the tooth. If the pain is severe or you have a swelling, telephone us and say so: see emergency root canal treatment.