Toothache Causes — Why a Tooth Hurts

Decay is the most common reason a tooth starts to hurt. Bacteria break through the outer enamel, and once they reach the softer dentine underneath, the tooth can become sensitive to sweets, cold, and pressure. Caught early, decay is usually treated with a filling. Larger areas may need a crown, and decay that reaches the nerve usually needs root canal treatment.

Cracked teeth are a common source of sharp pain on biting, particularly on back teeth. The crack can be tiny and not visible from the surface. Cold may also trigger discomfort. Treatment depends on how deep the crack goes — see our cracked tooth page for more.

An abscess is a localised collection of pus, usually caused by an infection at the root of a tooth or in the gum. It tends to cause throbbing, build-up pain, sometimes with swelling, a bad taste, or a pimple-like spot on the gum. An abscess needs prompt attention — see our dental abscess page.

Sensitivity is short, sharp pain triggered by cold, sweet, or sour foods. It is most often caused by exposed dentine at the gum line or by worn enamel. It usually settles between triggers and is rarely associated with swelling. Our sensitive teeth page goes through the causes and the home and in-chair options.

Grinding teeth at night can leave them sore, dull, and tired-feeling in the mornings. You may also notice headaches or jaw pain. A nightguard can protect the teeth and reduce the load on the jaw.

Inflamed or receding gums can cause discomfort and sensitivity, especially around a particular tooth. Persistent bleeding when brushing or flossing is worth investigating — our gum disease treatment page covers the assessment and management.

Fillings do not last forever. As they wear, leak, or fracture, decay can develop underneath and the tooth becomes sensitive. Our replacing old fillings page goes through when replacement makes sense.

Erupting or impacted wisdom teeth can cause aches at the back of the mouth, soreness when biting down, or repeated gum infections (pericoronitis). See our wisdom teeth hub for more.

The roots of the upper back teeth sit very close to the maxillary sinuses. When the sinuses are inflamed — for example with a cold, hayfever, or a sinus infection — pressure can refer down to the teeth and feel like toothache. The pain often affects several teeth at once, gets worse when you lean forward, and settles when the sinus issue clears.

A recent knock, fall, or hard bite can leave a tooth bruised, sore, or cracked. See our broken tooth page if the tooth has visibly chipped.

Pain in the teeth is sometimes coming from somewhere else — the jaw joint (TMJ), nearby muscles, or even a tooth on the opposite side. We can usually narrow this down with examination and imaging.

Sensitivity sometimes settles, but pain coming from decay, a crack, or an infection rarely resolves without treatment. Mild discomfort is worth booking in for a check; severe, swelling, or build-up pain is urgent.

Lying down increases blood pressure around the head, which can intensify throbbing pain from an inflamed nerve. Propping your head up may help while you wait to be seen.

Yes. The upper back teeth sit just below the sinuses, and sinus inflammation can refer down. The pain usually involves several teeth, feels dull and pressure-like, and shifts when you lean forward.

Cracks, decay between teeth, gum recession, sinus issues, and grinding can all cause pain without anything obvious on the surface. Imaging and a thorough exam usually identify the cause.

You can manage minor discomfort short-term, but pain that persists, builds up, or comes with swelling needs assessment. Untreated infections can spread, and a cracked tooth often gets worse the longer it is left.

Treat it the same way — gentle pain relief, soft cool foods, and a prompt dental visit. Our children’s dentistry hub covers what an appointment looks like for younger patients.

Only if the nerve inside the tooth is inflamed or infected beyond repair. Many toothaches are settled with a filling or by addressing sensitivity or gum issues. Your dentist will explain the options after examining the tooth.