Toothaches have a wide range of causes, from cavities and cracked teeth to gum infections and even sinus pressure. About 1 in 5 adults experience a toothache in any given year, making it one of the most common reasons people seek dental care. Understanding what’s behind the pain can help you recognize whether you’re dealing with something minor or something that needs prompt attention.
Tooth Decay and Pulp Inflammation
Cavities are the single most common reason teeth hurt. A cavity starts in the outer enamel, where it typically causes no pain at all. The trouble begins when decay works its way deeper into the softer layer called dentin, and eventually reaches the pulp, the living tissue at the center of the tooth that contains nerves and blood vessels. Once bacteria reach that inner chamber, the pulp becomes inflamed, a condition called pulpitis.
There are two stages worth knowing about because they feel different and have very different outcomes. In the early stage, you’ll feel a sharp sting when something cold or sweet touches the tooth, but the pain disappears within a couple of seconds once you remove the trigger. At this point, the tooth can usually be saved with a filling. In the later stage, pain lingers for 30 seconds or more after the trigger is gone, strikes without any trigger at all (often waking you at night), and can radiate to your ear or jaw. This happens because swelling inside the rigid shell of the tooth cuts off blood flow, and the pulp tissue starts to die. A tooth in this condition typically needs a root canal or extraction.
Cracked or Fractured Teeth
A cracked tooth produces a distinctive kind of pain that can be tricky to pin down. The hallmark is sharp, erratic pain when you chew, particularly at the moment you release your bite rather than when you first clamp down. Sensitivity to hot and cold is also common. Breathing through your mouth on a cold day may be enough to trigger it.
Cracks can result from biting something hard, a blow to the face, or years of grinding. Small cracks don’t always show up on X-rays, which is one reason this type of toothache sometimes takes more than one dental visit to diagnose. The earlier a crack is caught, the better the odds of saving the tooth. Left alone, a crack can deepen until bacteria reach the pulp, creating the same irreversible inflammation described above.
Dental Abscesses
An abscess is a pocket of infection that forms either at the tip of a tooth’s root (periapical abscess) or in the surrounding gum tissue (periodontal abscess). Both types cause intense, throbbing pain, but they originate in different places. A periapical abscess starts inside the tooth, usually as a complication of deep decay or a dying nerve. A periodontal abscess starts in the gums, often related to advanced gum disease or a trapped piece of food.
Common symptoms of a dental abscess include:
- Severe, throbbing pain that can radiate to the ear, neck, or jaw
- Pain when chewing or biting
- Sensitivity to heat and cold
- Swollen gums or face
- A bad taste in your mouth from draining pus
- Swollen lymph nodes in the neck
Abscesses don’t resolve on their own. The infection can spread to the jaw, neck, and in rare cases, the brain. If facial swelling is accompanied by fever, difficulty swallowing, or trouble breathing, that is a medical emergency. These signs mean the infection is spreading rapidly and you should go to an emergency room, not wait for a dental appointment.
Gum Disease
Gum disease (periodontal disease) is a slower-burning cause of tooth pain. In its early stages, called gingivitis, you’ll notice bleeding when you brush and mild tenderness. As it progresses, the gums pull away from the teeth, forming pockets where bacteria collect. This can lead to deeper infection, bone loss, and a dull aching pain around several teeth rather than a sharp pain in one specific spot.
Receding gums also expose the root surfaces of your teeth, which lack the protective enamel covering the crown. That exposed root is full of tiny channels leading to the nerve, so hot coffee, cold water, or even a breeze can cause a stinging sensation. If multiple teeth suddenly feel sensitive, receding gums are a likely culprit.
Teeth Grinding (Bruxism)
If your teeth or jaw ache most in the morning and improve as the day goes on, nighttime grinding is a strong possibility. Many people grind or clench without realizing it, especially during periods of stress or disrupted sleep. The constant pressure strains the teeth, jaw muscles, and the joint that connects your jaw to your skull.
Over time, grinding can wear down enamel, crack teeth, and cause chronic facial pain and headaches. You might also notice earaches, ringing in your ears, or difficulty opening your mouth wide. A custom night guard from a dentist is the most common way to protect the teeth and reduce symptoms, though addressing underlying stress or sleep issues helps too.
Loose or Damaged Fillings
Old fillings can loosen, crack, or fall out entirely, leaving the tooth exposed underneath. Because the tooth was already compromised enough to need a filling in the first place, the exposed area is especially vulnerable. Bacteria slip into the gap, food packs in, and you get sensitivity or outright pain that feels a lot like a new cavity. If a filling feels rough, sharp, or seems to shift when you bite down, it likely needs to be replaced before the damage gets worse.
Sinus Pressure
Not every toothache starts in the mouth. Your largest sinuses sit directly above the roots of your upper back teeth, and in some people the tooth roots actually extend into the sinus cavity. When those sinuses become inflamed from a cold, allergies, or a sinus infection, the pressure can produce a dull, aching pain in the upper molars that feels exactly like a dental problem.
A few clues point toward a sinus-related toothache rather than a cavity. The pain usually affects multiple upper teeth rather than a single tooth, gets worse when you bend forward or lie down, and comes alongside nasal congestion, facial pressure, or postnasal drip. If your dentist examines the area and finds no dental cause, the next step is evaluating your sinuses.
Other Non-Dental Causes
Several conditions outside the mouth can produce pain that feels like it’s coming from a tooth. Tension headaches and migraines sometimes refer pain to the jaw and teeth. Temporomandibular joint (TMJ) disorders cause aching in the jaw area that can be mistaken for a toothache, especially when chewing is involved. In rare cases, pain radiating to the lower left jaw can even be a sign of a cardiac event, particularly if it comes with chest tightness or shortness of breath.
Neuralgia, where a facial nerve fires pain signals without a clear trigger, can also mimic a toothache. The pain tends to be sudden, electric, and severe, lasting seconds to minutes before disappearing. People with this condition sometimes undergo unnecessary dental work before the real source is identified.
Warning Signs That Need Urgent Care
Most toothaches warrant a dental visit within a few days, but some situations call for immediate action. Seek emergency care if you experience facial swelling that spreads to the eye or neck, fever alongside dental pain, difficulty swallowing or breathing, uncontrolled bleeding, or a jaw injury from trauma. Dental infections can become life-threatening when they spread beyond the tooth, and these symptoms indicate that process may already be underway.