What Causes Tooth Pain? The Common Culprits Explained

The most common causes of tooth pain

Most tooth pain starts in the tooth itself, and a short list of problems accounts for the bulk of it. These are the ones we see most, running from the everyday to the urgent.

• Decay (a cavity). The most common cause by far. Bacteria wear a hole through the enamel, and once the decay gets near the nerve the tooth starts to ache, especially to sweet and cold. Caught early it needs a filling; left too long it becomes a choice between a deep filling and a root canal.
• A cracked or broken tooth. A crack from grinding, an old filling, or biting something hard can flex under pressure and set off a sharp pain when you bite. See our guides on a cracked tooth and repairing a broken tooth.
• An abscess or infection. When decay or a crack lets bacteria reach the nerve, the nerve dies and infection builds at the root, which is a dental abscess. This is the deep, throbbing, keep-you-up kind of pain, and the one most likely to need urgent care.
• Gum problems. Inflamed or receding gums can ache in their own right and expose the sensitive root of the tooth. Our post on sore, inflamed gums covers the causes and what helps.
• A lost or worn filling. When an old filling cracks or falls out, the soft inner tooth is suddenly open to temperature and pressure, and it can be tender for days. Some ache after a new filling is normal too, and usually settles on its own.
• Sensitivity. Worn enamel or an exposed root gives you a short, sharp response to cold, heat, or sweet that fades quickly. Our guide to what causes sensitive teeth explains the difference between sensitivity and a true toothache.
• A wisdom tooth. One pushing through at an angle, or half-covered by gum, can ache and trap food behind it. See wisdom tooth pain for when it needs attention.

What the type of pain is telling you

The way a tooth hurts narrows down the cause more than most people realise. It is not a diagnosis, but it is a good place to start.

• A short, sharp zing to cold or sweet that goes as soon as the trigger does usually means sensitivity or early decay, not a dying nerve. More on teeth that are sensitive to cold.
• Pain to heat, or pain that lingers after something cold has gone, points to a nerve that is inflamed or dying, which often means root canal territory. See sensitivity to heat and the signs of a dead tooth.
• Pain when you bite down tends to be a cracked tooth or a filling that sits too high, since both flex or press under the load of a bite.
• A deep, constant throb you can feel in your pulse usually means infection. A throbbing toothache is the one least likely to settle on its own.
• Pain that comes and goes can be an early problem flaring up and calming down, and it is easy to ignore between rounds. Our post on tooth pain that comes and goes explains why that pattern is worth acting on.

Causes that aren't the tooth at all

Sometimes the tooth is fine and the pain is being referred from nearby. This is worth knowing, because treating a healthy tooth will not help.

• A sinus infection. The roots of the upper back teeth sit right against the sinus, so a cold or sinus infection can make several upper teeth ache at once. Our guide on sinus pain that feels like a toothache covers how to tell them apart.
• Grinding and jaw strain. Clenching or grinding, often at night, can leave teeth sore and the jaw aching. See tooth pain from grinding and jaw pain linked to a tooth.
• Ear and jaw referral. Because the nerves are shared, a back tooth and an ear can each feel like the other. Our post on ear pain coming from a tooth untangles it.

One rarer cause is not dental at all. Pain in the lower jaw or teeth that comes on with exertion, alongside chest pressure, arm pain, or shortness of breath, can be a heart symptom. That is a reason to call emergency medical services, not a dentist.

How a dentist finds the cause

Finding the cause is mostly a process of elimination. We tap the tooth, test it with cold, check how it feels to bite, and look at the gum around it. An X-ray then shows what the eye cannot: decay under a filling, infection at the root, or a crack below the gum line. Our post on what a dental X-ray shows walks through it.

Waiting to see if it settles is usually the more expensive choice. A tooth that needs a simple filling this week can need a root canal next month, so the sooner the cause is found, the smaller the fix tends to be. If you are not sure it is worth a visit yet, you can send a photo or a recent X-ray first and we will tell you honestly.

When tooth pain can wait, and when it can't

Not every twinge needs an appointment, and it is fair to say so. A mild ache that eases with a painkiller, a brief sensitivity to cold, or a tooth that settles the moment you floss out some trapped food can usually wait for a routine visit. Our guide on easing a toothache at home can hold you over.

Be seen within a day or two if the pain keeps you awake, comes straight back as the painkiller wears off, or has lasted more than a couple of days. And do not reach for leftover antibiotics: antibiotics alone do not cure a tooth infection, and the tooth still needs treating.

Go straight to a hospital emergency room, not a dental clinic, if you have swelling spreading toward your eye or down your neck, a fever with chills, or any trouble breathing or swallowing. That is an infection that has moved beyond the tooth. Our posts on when a toothache is a real emergency and facial swelling from a tooth set out where that line sits.

Whatever is behind it, the fix starts with finding the cause, and most causes are easier and cheaper to treat the earlier they are caught. If your tooth has been hurting for more than a day or two, it is worth having looked at rather than waited out.

We treat tooth pain and the causes behind it at our emergency dental clinic in Beit Shemesh, at Harav Kook 28/1. Call or WhatsApp 055-985-8845, Sunday to Thursday 8:00 AM to 8:00 PM and Friday 8:00 AM to 2:00 PM, with after-hours emergency treatment outside those hours. If the cause turns out to be an infected nerve, we will tell you plainly whether it needs a root canal or something simpler.

For guidance from sources with nothing to sell, the American Dental Association's MouthHealthy runs through common dental symptoms and what they mean, and the American Association of Endodontists explains what different kinds of tooth pain point to.