Why does my tooth hurt when I bite down?

Common causes of pain when you bite

Healthline's page on tooth pain when biting lists the main causes, and Cleveland Clinic's toothache page overlaps.

• Cavity: a hole in the tooth, often present before symptoms appear.
• Cracked tooth: sharp pain may occur when you release a bite, and some people have no symptoms.
• Abscess: pain that lingers or worsens, often with gum swelling.
• Loose filling or crown: can let bacteria irritate the tooth and nerve.
• Bite problem (malocclusion): teeth that do not meet properly can wear unevenly or cause pain in the tooth or jaw.
• Gum disease: tender, red or bleeding gums, plaque build-up, bad breath, and receding gums that expose the root.
• Sinus congestion: a sinus toothache, usually in the upper back teeth, sometimes affecting several teeth.
• Pulp necrosis: dying pulp tissue, with sensitivity to heat, cold and sweets.

Why does my tooth hurt after a filling when I bite?

A bite problem is the most common cause of pain after a filling, according to Healthline's sensitivity page: a filling that sits taller than the other teeth causes pain when you close your mouth, and biting on it can crack the filling. Contact your dentist as soon as you suspect it, since the dentist can adjust the filling. Healthline's bite page also notes that a loose filling or crown can irritate the tooth and nerve.

Why do toothaches hurt more at night?

Healthline says lying down may let blood pool in your head, which can increase pressure and intensify tooth pain, that without daytime distractions you may notice the pain more, and that pain relievers may wear off by bedtime. Its suggestions are to prop your head higher than your body, avoid acidic, cold or hard foods before bed, and hold a wrapped ice pack against the painful side of your face. That is an explanation from one source, not a diagnosis, so pain that wakes you needs a dentist.

Healthline also lists abscess symptoms as pain when chewing or lying down, pain that radiates to the ear, jaw or neck, and swelling, so worsening night pain with swelling or fever is urgent.

What helps until you are seen

The sources describe temporary measures only. Cleveland Clinic lists a warm salt water rinse, a wrapped ice pack on the jaw for about 20 minutes several times a day, and over-the-counter acetaminophen or ibuprofen. Healthline's bite page says that while awaiting a replacement filling or crown, an over-the-counter pain reliever may help, as a dentist suggests, and that for sinus-related pain a humidifier, warm compress, steamy shower or saline spray may help. Follow the label and ask a pharmacist if unsure. These do not treat the cause.

How dentists treat each cause

Healthline lists a filling, crown, pulp cap or root canal for a cavity; repair of small cracks and extraction for extensive cracks; orthodontics, tooth reshaping, crowns or extraction for a bite problem; scaling and root planing, possibly with surgery, for gum disease; a replacement filling or crown for a loose one; a root canal and crown or extraction for pulp necrosis; and drainage and cleaning, possibly a root canal or extraction, plus antibiotics for an abscess.

When it could be the sinuses

Healthline says sinus pain usually affects several upper back teeth, comes with congestion or facial pressure, and may worsen when you bend over, whereas dental pain often comes from one tooth. If a dentist finds no dental cause, see a doctor. Our toothache guide explains more.

Why seeing a dentist matters

Healthline says any tooth pain warrants speaking with a dentist, since it can signal a larger problem that may worsen, and to see one as soon as possible if pain comes on suddenly and is intense. Cleveland Clinic advises calling a dentist right away for a toothache lasting more than two days, swelling or pain when opening wide.

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