Teeth ache for a wide range of reasons, from exposed nerve endings and hairline cracks to sinus pressure and nighttime grinding. About 24% of adults worldwide experience a toothache in any given year, so if your teeth hurt right now, you’re far from alone. The key to figuring out what’s going on is paying attention to when the pain happens, what triggers it, and exactly where you feel it.
How Teeth Sense Pain
Underneath your enamel sits a layer called dentin, which is riddled with microscopic fluid-filled tubes that connect to the nerve inside your tooth. When enamel wears down or gum tissue pulls back, those tubes become exposed. Hot coffee, cold air, sugary foods, or even a blast of wind can cause the fluid inside those tubes to shift, and your nerve reads every shift as pain. This is why sensitivity often feels sharp and sudden rather than dull and constant.
The situation gets worse if the area around those exposed tubes becomes inflamed. Inflammation raises the pressure inside the tooth, pushing fluid outward more aggressively. It can also cause the nerve endings to multiply, a process called nerve sprouting, which means more of the tooth’s surface becomes wired to feel pain. What started as a wince when you drank ice water can gradually become a persistent ache.
Decay and Infection
The most common reason for a true, lingering toothache is a cavity that has worked its way deep enough to irritate or infect the nerve. Early cavities often cause no pain at all. By the time a tooth aches on its own, without any trigger, decay has typically reached the inner pulp or is close to it. The pain can be throbbing, constant, and worse when you lie down because blood flow to your head increases in that position.
If a cavity goes untreated long enough, bacteria can reach the root tip and form an abscess, a pocket of infection in the bone. An abscess often produces a dull, deep ache that radiates into the jaw, along with swelling, a bad taste in your mouth, or a small pimple-like bump on the gum near the affected tooth. Facial swelling, fever, or difficulty swallowing are signs the infection may be spreading and needs same-day attention.
Cracked or Fractured Teeth
A cracked tooth can be maddeningly hard to pin down. The hallmark symptom is a sharp jolt of pain when you bite down, or more specifically, when you release the bite. That release allows the two sides of the crack to flex apart, tugging on the nerve. You might also notice sensitivity to hot, cold, or sweet foods, but only on that one tooth. Swelling around the gum line near a single tooth is another clue.
Cracks don’t always show up on standard X-rays. Dentists often diagnose them by having you bite on a stick tooth by tooth, shining a light through the enamel to illuminate a fracture line, or applying a staining dye that seeps into the crack and makes it visible. A 3D cone beam CT scan can reveal fractures that other imaging misses.
Grinding and Clenching
If your teeth ache first thing in the morning or after a stressful day, grinding (bruxism) is a likely culprit. You may not even know you’re doing it. Nighttime grinding generates forces several times stronger than normal chewing, and that sustained pressure compresses the ligament that cushions each tooth in its socket. The result is a broad, sore feeling across multiple teeth rather than one pinpoint spot.
Other signs that grinding is behind your pain include:
- Headaches or facial soreness concentrated around the temples or jaw, especially in the morning
- Earaches or ringing in the ears with no ear infection
- Worn, flattened, or chipped tooth edges visible in a mirror
- Jaw stiffness or difficulty fully opening your mouth
A custom night guard from a dentist is the standard fix. It doesn’t stop the grinding, but it absorbs the force so your teeth and jaw joints take less damage overnight.
Sinus Pressure
Your upper back teeth sit directly beneath your maxillary sinuses, the largest pair of sinus cavities in your skull. The roots of those teeth are so close to the sinus floor that they sometimes poke into it. When sinuses become inflamed from a cold, allergies, or a sinus infection, the swelling and pressure push down on those roots and create pain that feels exactly like a toothache.
The giveaway is that the aching hits several upper teeth at once, usually premolars and molars on both sides. It tends to get worse when you bend forward, and it may come with nasal congestion, post-nasal drip, or pressure across your cheekbones. If the “toothache” fades as your congestion clears, your sinuses were the real problem.
Gum Recession and Periodontal Disease
Gums that have pulled away from the teeth expose the root surface, which has no enamel protection. Root surfaces are covered by a thinner, softer layer called cementum that wears away quickly once exposed, leaving dentin and its sensitive fluid-filled tubes open to everything in your mouth. The pain tends to be a quick, electric zing triggered by cold drinks, brushing, or acidic foods like citrus.
When gum disease progresses further, the bone supporting the teeth begins to break down. Teeth can become slightly loose, and biting pressure that once felt normal starts to cause a deep, achy soreness. Persistent bad breath, bleeding when you floss, and gums that look puffy or have pulled away from the teeth are signs that periodontal disease, not just normal sensitivity, is at play.
Managing the Pain at Home
For short-term relief while you figure out next steps, ibuprofen and acetaminophen are the most effective over-the-counter options. For mild pain, 400 mg of ibuprofen every six hours is a solid starting point. For moderate to severe pain, combining ibuprofen (400 to 600 mg every six hours) with acetaminophen (500 to 650 mg every six hours) works better than either drug alone, because they reduce pain through different pathways. Keep your total acetaminophen from all sources under 3,000 mg per day.
A few other things can help in the short term. Rinsing with warm salt water reduces bacteria and soothes inflamed gum tissue. Avoiding very hot, very cold, or sugary foods limits the fluid shifts in exposed dentin that trigger sharp pain. Sleeping with your head slightly elevated can reduce the throbbing that gets worse when you lie flat. Desensitizing toothpaste containing potassium nitrate can calm nerve sensitivity over a week or two of regular use, though it won’t fix the underlying cause.
Signs That Need Urgent Attention
Most toothaches are uncomfortable but not dangerous. A few patterns, however, signal something that can escalate quickly. Facial swelling that spreads toward the eye or down toward the neck, especially with fever, suggests an infection moving beyond the tooth. Difficulty swallowing or opening your mouth fully can mean swelling is encroaching on your airway. A foul taste that keeps coming back, combined with a throbbing ache, often points to a draining abscess. Any of these warrant same-day care rather than a wait-and-see approach.