Why Does My Tooth Hurt? Clues From Your Symptoms

A hurting tooth does not automatically mean a cavity. Decay, a crack, a damaged filling, exposed roots, gum disease and clenching can all cause pain. Sometimes the ache comes from nearby sinuses rather than the tooth itself. What triggers the pain, how long it lasts and where you feel it are useful clues—not a diagnosis.

First, decide how urgently to get help

Seek emergency medical care for swelling around an eye or in the neck, or mouth or neck swelling that makes breathing, swallowing or speaking difficult. Call a dentist promptly for facial or jaw swelling, fever, pus or a bad taste, or severe pain that painkillers do not control. Even without those signs, toothache lasting more than two days needs a dental appointment. These recommendations follow NHS toothache guidance and the Merck Manual; you do not need to wait two days if symptoms are worsening.

What different pain patterns can suggest

A quick zing with cold, heat or sweet foods

Brief sensitivity can happen when worn enamel or receding gums expose dentin, the layer beneath the tooth’s protective outer covering. Dentin contains tiny channels that transmit sensations toward the inside of the tooth. But cavities, fractured teeth and worn fillings can cause sensitivity too, according to the American Dental Association.

A soft toothbrush and sensitivity toothpaste may help, as the American Association of Endodontists recommends for momentary temperature sensitivity. Improvement does not establish the cause, and persistent symptoms still deserve a dental check.

Pain that lingers—or starts without eating or drinking

Pain that continues after a hot or cold drink is gone is more concerning than a momentary zing. It can suggest inflammation or damage to the pulp, the soft tissue containing nerves and blood vessels inside the tooth. Deep decay, injury and previous dental work can affect this tissue. Pulp inflammation can also cause pain without an obvious trigger, explains the Merck Manual.

The American Association of Endodontists advises prompt evaluation for lingering temperature pain. The symptom alone does not establish whether you need a root canal.

Sharp pain when biting—or when releasing a bite

Decay, a loose filling or a crack can cause a sharp jolt when chewing. Pain as you release biting pressure is another clue that a crack may be involved. Cracked-tooth pain can come and go, and even the affected tooth can be difficult to identify, according to the American Association of Endodontists.

Avoid chewing on that side while arranging an examination. Intermittent pain is not proof that the problem has healed.

Constant pain with pressure or a swollen gum

An abscess—a collection of pus associated with infection—can cause constant pain, tenderness when chewing and swelling near the tooth. Inflammation around a tooth’s root can also hurt when biting, even without visible swelling. These overlapping patterns are described in the Merck Manual’s toothache guide.

Pain intensity alone cannot distinguish an abscess from other causes. A dentist needs to locate the source.

Soreness near the gumline or behind the last molar

Gum disease can cause tender or bleeding gums, sensitive or loose teeth, and painful chewing, according to NIDCR. Pain that seems to come from a tooth may therefore involve its supporting tissues.

Farther back, inflammation or infection around a partly erupted wisdom tooth can cause a dull ache, swollen gum tissue and difficulty opening the mouth. The Merck Manual calls this pericoronitis.

A broader ache across teeth, with jaw tension or sinus symptoms

Grinding can cause a dull ache and pressure in the teeth and jaw. Grinding or clenching can occur while awake or asleep, so you may not notice the habit. Jaw tiredness and headaches are additional clues; severe grinding can damage teeth, explains NIDCR.

Sinus inflammation can instead feel like pain in several upper back teeth, especially alongside a cold, nasal discharge or facial pressure. Pain may change when you bend forward. These clues suggest—but do not prove—a sinus source, according to the Merck Manual.

What to tell—and ask—the dentist

Start with a general dentist unless you have been directed elsewhere. Tell the office:

• Which tooth or area hurts, and whether you can pinpoint it.
• Whether cold, heat, sweets, biting or releasing a bite triggers it.
• Whether pain stops quickly, lingers or begins on its own.
• Whether you recently had dental work, an injury, swelling or a cold.

The examination may include temperature testing, gentle tapping, gum measurements and dental X-rays. These help separate problems inside the tooth from cracks, gum disease and other sources. Merck Manual and NIDCR describe these assessments.

Before agreeing to treatment, ask: “What findings explain the pain, and what alternatives did you rule out?” If a specialist is recommended, ask whether the concern is inside the tooth or in its supporting gums and bone; our guide to periodontists versus endodontists explains the distinction.

While waiting, choose soft foods, avoid chewing on the sore tooth and avoid very hot or cold foods. A pharmacist can advise on an appropriate pain reliever. These temporary measures ease discomfort; they do not identify or repair its cause. If symptoms began after a filling, see our more specific guide to post-filling sensitivity.