Tooth pain has dozens of possible causes, but most cases trace back to a handful of common culprits: sensitivity from exposed inner tooth layers, cavities that have reached the nerve, gum disease, grinding, or infection. The type of pain you’re feeling, how long it lasts, and what triggers it can tell you a lot about what’s going on.
Tooth Sensitivity
If your teeth hurt briefly when you drink something cold or eat something sweet, you’re likely dealing with dentin hypersensitivity. About one in eight dental patients has it, though estimates range widely depending on the population studied. It happens when the hard outer shell of your tooth wears down and exposes the softer layer underneath, which is full of microscopic tubes that lead toward the nerve. When cold air, ice water, or sugary foods hit that exposed surface, fluid inside those tiny tubes shifts and triggers a sharp, quick burst of pain. Roughly 75% of people with this condition say cold is the worst trigger.
The outer layer wears away for a few key reasons. Acid from foods and drinks (citrus, soda, wine, coffee) slowly dissolves it over time. Stomach acid from acid reflux or frequent vomiting does the same thing, often more aggressively. Brushing too hard or using a stiff-bristled toothbrush can physically scrub it away, especially along the gumline where the protective layer is thinnest. Once that surface is gone, it doesn’t grow back.
Cavities and Deeper Decay
A cavity that’s still shallow might cause occasional sensitivity to sweets or cold that disappears quickly. That’s a sign the inner tissue of your tooth is irritated but still healthy enough to recover once a dentist places a filling. At this stage, the pain tends to be sharp but brief.
When decay reaches deeper, the inflammation becomes more serious. Pain shifts from fleeting to lingering. You might notice a throbbing or aching sensation that sticks around for more than a few seconds after eating or drinking something hot, cold, or sweet. Heat sensitivity, in particular, is a red flag that the damage has progressed. At this point, a simple filling may no longer be enough. If the tissue inside the tooth dies entirely, the temperature sensitivity can actually disappear, but the tooth will still hurt when pressure is applied to it. The absence of sensitivity doesn’t mean the problem is gone.
Gum Disease
Gum problems are easy to overlook because they develop gradually. Early signs include red, swollen, or bleeding gums, especially when brushing or flossing. As the disease progresses, gums pull away from the teeth, making them look longer than usual. This recession exposes the root surface, which lacks the same protective coating as the crown of the tooth, leading to sensitivity and pain.
More advanced gum disease creates deep pockets between the teeth and gums (healthy pockets measure 1 to 3 millimeters). These pockets trap bacteria, which can destroy the bone supporting your teeth. At that stage, teeth feel loose, chewing becomes painful, and persistent bad breath is common. Bone loss from gum disease doesn’t reverse on its own.
Grinding and Clenching
Many people grind their teeth at night without realizing it. Over time, grinding flattens the biting surfaces, chips edges, and wears through the outer layer of the tooth, exposing sensitive inner layers. Cracks can also form, sometimes so small they’re invisible to the naked eye but large enough to send a jolt of pain through the tooth when you bite down at a certain angle.
Beyond the teeth themselves, grinding strains the jaw muscles. You might wake up with a sore jaw, tight facial muscles, or a dull headache that radiates from the temples. If your teeth look visibly flattened or you notice small chips you can’t explain, nighttime grinding is a strong possibility.
Tooth Abscess
An abscess forms when bacteria invade the inner tissue of a tooth or the gum around it, creating a pocket of infection. The pain is hard to ignore: severe, constant, throbbing, and often radiating into the jawbone, neck, or ear. Chewing or biting makes it worse. You may notice swelling in your face or cheek, tender lymph nodes under your jaw, a foul taste in your mouth, or a fever.
Abscesses don’t resolve without treatment. If the infection spreads beyond the tooth, it can move into the jaw, throat, or neck. Fever combined with facial swelling, difficulty breathing, or trouble swallowing are signs the infection is becoming systemic. In rare cases, this can progress to sepsis, a life-threatening condition. These symptoms warrant emergency care.
Sinus Pressure
Your upper back teeth sit very close to your sinus cavities. When your sinuses are inflamed from a cold, allergies, or a sinus infection, the pressure can make those upper teeth ache. The giveaway is that the pain usually affects several teeth at once rather than a single tooth, and it comes with congestion, a runny nose, facial pressure, or a foul smell. The teeth themselves are healthy; they’re just caught in the crossfire of nearby inflammation.
A pattern of recurring, one-sided sinus infections can sometimes point to a dental problem that’s actually causing the sinus issue rather than the other way around. In those cases, a tooth with a dead nerve or a failed root canal may be quietly draining bacteria into the sinus. This is worth investigating if sinus infections keep coming back on the same side.
Pain After a Dental Procedure
If your tooth started hurting after a recent filling, that sensitivity is usually normal. The first two days tend to be the worst. Most people notice significant improvement by days three through five, and shallow to moderate fillings typically stop causing discomfort within two weeks. Deeper fillings placed close to the nerve can take three to four weeks to fully settle. If the pain is getting worse instead of better after the first few days, or if it lingers for more than a month, something may need to be adjusted.
Temporary Relief at Home
While you’re waiting to see a dentist, an over-the-counter pain reliever can help take the edge off. Don’t place aspirin or any painkiller directly against the gum tissue, as it can cause chemical burns. If the pain followed an injury to the tooth, hold a cold compress against the outside of your cheek. Avoid very hot, very cold, or sugary foods and drinks that tend to make sensitivity worse.
Over-the-counter numbing gels containing benzocaine were once a go-to recommendation, but they carry a small risk of a serious condition that reduces the blood’s ability to carry oxygen. If you’re considering one of these products, check with a dentist or pharmacist first, especially before using them on children.