A toothache usually means something is irritating the nerve inside or around a tooth. The most common cause is a cavity that has grown deep enough to reach the sensitive inner layers, but tooth pain can also come from cracked teeth, gum disease, grinding, infections, and even sinus pressure. Figuring out the likely cause starts with paying attention to where the pain is, what triggers it, and how long it lasts.
Cavities and Tooth Decay
Tooth decay is the single most common reason for a toothache. It starts when bacteria in plaque produce acid that eats through enamel, the hard outer shell of your tooth. Early cavities often cause no pain at all, which is why they can go unnoticed for months. The trouble begins when decay reaches dentin, the softer layer beneath the enamel. Dentin is far less resistant to acid and contains tiny channels that connect to the nerve, making the tooth noticeably sensitive to sweets, cold drinks, or hot food.
If the decay keeps advancing, bacteria eventually reach the pulp, the innermost tissue packed with nerves and blood vessels. The pulp swells in response to the infection, but because it’s sealed inside a rigid tooth, there’s nowhere for the swelling to go. The nerve gets compressed, and the result is intense, throbbing pain that can wake you up at night. At this stage, damage can spread beyond the tooth root into the surrounding bone, sometimes affecting neighboring teeth as well. Brown, black, or white spots on a tooth surface and pain when you bite down are classic signs that decay has progressed past the early stage.
Cracked or Fractured Teeth
A crack in a tooth can be surprisingly hard to pin down. The hallmark symptom is sharp, erratic pain when you chew, especially at the moment you release biting pressure. You might also notice sudden sensitivity to hot or cold temperatures that comes and goes unpredictably. Because the pain isn’t constant, you (and even your dentist) may struggle to identify which tooth is the problem.
Cracks develop from injuries, biting down on something hard, or years of general wear and tear. Over time a cracked tooth tends to get worse. What starts as occasional discomfort during meals can eventually become a steady ache, particularly if the crack extends deep enough to expose the nerve.
Dental Abscesses
When infection at the root of a tooth or in the gum tissue forms a pocket of pus, that’s an abscess. The two main types feel somewhat different. An abscess at the root tip (from deep decay or a failed filling) tends to cause persistent, throbbing pain that radiates into the jaw or ear. A gum abscess typically shows up as a swollen, tender bump on the gum line, sometimes with pus and a bad taste in your mouth. You may feel like the tooth is slightly raised or loose, and biting can make the pain worse.
Abscesses don’t resolve on their own. Left untreated, infection can break down the bone supporting the tooth, and in rare cases spread to the head, neck, or bloodstream. Fever, facial swelling, swollen lymph nodes in the neck, or difficulty swallowing alongside tooth pain are signs the infection is spreading and needs prompt attention.
Gum Disease
Gingivitis, the earliest stage of gum disease, doesn’t usually cause pain. It shows up as red, puffy gums that bleed when you brush or floss. The real trouble starts if it progresses to periodontitis, where the infection reaches the bone beneath your gums. At that point, you begin losing the bone that holds your teeth in place, a permanent change that can’t be fully reversed.
Periodontitis can cause tenderness or pain when chewing, loose teeth, and receding gums that make teeth look longer than they used to. The discomfort tends to be more of a dull ache around the gum line rather than the sharp, focused pain of a cavity. If you notice your teeth shifting position or feel any looseness, that’s a strong signal that bone loss is already underway.
Teeth Grinding (Bruxism)
If your toothache is worst in the morning and spread across several teeth rather than focused on one, grinding or clenching during sleep is a likely culprit. Bruxism puts enormous pressure on teeth and jaw joints, leading to generalized soreness, jaw tightness, tired facial muscles, and headaches that start near the temples. Over time, severe grinding can wear down enamel, flatten chewing surfaces, and even crack teeth.
Most people who grind at night don’t realize they’re doing it until a dentist spots the wear patterns or a partner hears the sound. A custom mouth guard worn during sleep is the standard fix. It separates the teeth so they can’t damage each other and reduces the muscle activity that drives the clenching.
Wisdom Teeth and Pericoronitis
Pain at the very back of your mouth, particularly in your late teens or twenties, often points to a wisdom tooth that’s partially erupted or stuck beneath the gum. When a tooth is only halfway through, a flap of gum tissue partially covers it and traps food and bacteria underneath. The resulting infection is called pericoronitis, and it can range from a mild, temporary ache to severe pain with facial swelling, pus, bad breath, fever, and even difficulty opening your mouth or swallowing.
Chronic pericoronitis tends to flare up periodically with mild discomfort and a bad taste, then settle down, then return. Acute episodes are harder to ignore, with intense pain and visible swelling around the back teeth.
Sinus Pressure Mimicking a Toothache
Your upper back teeth sit remarkably close to your maxillary sinuses. The roots of the upper second molars, in particular, can extend to within a millimeter or two of the sinus floor. When those sinuses are inflamed from a cold, allergies, or a sinus infection, the pressure can push down on the tooth roots and create pain that feels exactly like a toothache.
The giveaway is usually that multiple upper teeth hurt at the same time, the pain gets worse when you bend forward, and you also have nasal congestion, a feeling of facial pressure, or postnasal drip. If only one upper tooth hurts and you have no other sinus symptoms, it’s more likely a dental problem. But if several upper molars ache alongside a stuffy nose, treating the sinus congestion often makes the tooth pain disappear.
When Tooth Pain Isn’t About Your Teeth
Rarely, what feels like a toothache is actually referred pain from the heart. Cardiac-related jaw and tooth pain has a few distinguishing features. It tends to be bilateral (both sides), feel more like a burning or pressing sensation rather than the sharp throb of a true toothache, and often appears in multiple teeth at once without an obvious dental cause. The intensity is typically lower than genuine tooth pain, and it won’t respond to dental treatment or local anesthesia.
Heart-related episodes usually last between one and ten minutes, improve with rest, and may come alongside chest tightness, shortness of breath, or pain radiating to the arms or shoulders. True dental pain is essentially always on one side, can be pinpointed to a specific area, and never radiates to the chest or shoulders. If tooth pain doesn’t match any dental explanation, keeps returning despite treatment, and comes with any of those broader symptoms, it’s worth a cardiac evaluation.
Managing Pain Until You Get Help
For mild tooth pain, an over-the-counter anti-inflammatory like ibuprofen (400 mg every six hours) or acetaminophen (325 to 500 mg every six hours) is effective. Moderate pain responds better when you take both together on alternating schedules, since they work through different pathways and the combined effect is stronger than either one alone. Keep total acetaminophen from all sources under 3,000 mg per day.
Cold compresses on the outside of the cheek (20 minutes on, 20 minutes off) can help with swelling. Rinsing with warm salt water a few times a day reduces bacteria around an irritated area. Avoid very hot, very cold, or sugary foods and drinks that can trigger or intensify the pain. These steps buy you time, but they don’t fix the underlying problem. A toothache that persists beyond a day or two, wakes you at night, or comes with swelling, fever, or a foul taste needs professional evaluation before it progresses.