Why does my tooth hurt?

Toothache is a message, and the pattern of the pain usually says what is sending it. None of this replaces an examination, the same symptom can have several causes, but knowing the usual suspects takes some of the fear out of it, and helps you describe it when you call.

A sharp twinge with cold or sweet that fades quickly

Most often exposed dentine, the softer layer under the enamel, at a receded gum line or a worn spot, or a small early cavity. It stops within seconds of the trigger. This is sensitivity rather than an inflamed nerve, and it is usually a simple fix: a sensitivity toothpaste, a gentler brush, a small filling. The sensitive teeth explainer goes further.

Pain that lingers after hot or cold has gone

When the pain stays for a minute or more after the trigger, or comes on its own in the evening and throbs when you lie down, the nerve inside the tooth is inflamed, from decay that has reached it, a deep filling, or a crack. This is the pattern that does not settle by itself, and the usual answer is a root canal, which ends it.

A sharp pain on biting, then nothing

A cracked tooth, or a cusp that has fractured under an old filling. It hurts on release of biting pressure, often on one specific food, and is easy to miss on an X-ray. Caught early, a crown holds the tooth together; left, the crack travels.

A dull ache with a swollen, tender gum

Usually gum infection: an abscess beside a tooth with a deep gum pocket, or food packed between two teeth that have drifted. The gum is sore to touch, and the tooth may feel slightly high or loose. Cleaning the pocket settles most of these.

Pressure in the upper back teeth, worse when you bend forward

Several upper teeth aching at once, especially during or after a cold, often points to the sinus above them rather than the teeth. A dentist can tell the two apart, and the answer is usually the sinus clearing.

Soreness at the very back, with a swollen flap of gum

A wisdom tooth coming through, or partly through, with the gum over it inflamed. It comes in episodes. The wisdom tooth removal page explains when it is simply watched and when it is removed.

Teeth that ache in the morning, with a tired jaw

Grinding or clenching in your sleep, which loads every tooth. It often shows as generalised sensitivity and worn biting edges rather than one bad tooth. A night guard is one of the simpler answers.

What to do today

For any toothache, keep the area clean, avoid very hot and very cold, and take an ordinary painkiller as directed on the pack, never placed on the gum, which burns it. Call during clinic hours and describe the pattern; a tooth that is throbbing or keeping you awake is seen as an emergency. Swelling that affects the eye, the floor of the mouth or your breathing is urgent care at a hospital, not a dental appointment.