A toothache is pain in or around a tooth, typically caused by damage or irritation to the soft tissue (called the pulp) inside the tooth. It’s one of the most common pain complaints worldwide, affecting roughly 29% of adults in any given year. The pain can range from a mild, fleeting sting when you sip cold water to a deep, relentless throb that keeps you up at night.
Why Teeth Hurt
Your teeth aren’t solid blocks of bone. Beneath the hard outer enamel lies a chamber filled with soft tissue containing blood vessels and nerve fibers. These nerve fibers branch from the trigeminal nerve, which runs through your jaw and upper face, and they extend tiny endings into microscopic tubes that run through the tooth’s inner layer. When something irritates or damages those nerve endings, the signal travels through the trigeminal nerve to your brain, and you feel pain.
What makes tooth pain so intense is the anatomy itself. The soft tissue is locked inside a rigid shell. When infection or inflammation causes that tissue to swell, there’s nowhere for it to expand. The pressure builds against the inner walls of the tooth, compressing the nerves further. This is the same reason a toothache often feels like it has its own heartbeat: you’re literally feeling your pulse pressing against inflamed tissue inside a closed space.
Common Causes
Tooth decay is the most frequent cause. Bacteria in your mouth feed on sugars and produce acid that slowly dissolves enamel. Once that protective layer breaks down, bacteria enter the inner cavity and trigger a local infection. Early decay causes sensitivity. Deeper decay causes persistent, lingering pain.
Beyond cavities, several other problems produce toothaches:
- Cracked or fractured teeth expose the inner nerve to pressure changes when you bite down, producing sharp, sudden pain that disappears when you release.
- Gum disease causes inflammation and recession that leaves root surfaces exposed and sensitive.
- Dental abscesses form when infection spreads beyond the tooth into the surrounding bone and tissue, producing a constant deep ache often accompanied by swelling and fever.
- Impacted wisdom teeth trap bacteria between the partially erupted tooth and the gum, causing swelling, jaw pain, and difficulty opening your mouth.
- Teeth grinding (bruxism) wears down enamel over time and leaves teeth sore, particularly in the morning.
Some less obvious risk factors also contribute. Dry mouth, whether from medication or conditions that reduce saliva production, accelerates bacterial growth. Weakened enamel from genetic conditions makes teeth more vulnerable to wear. Smoking, particularly methamphetamine use, and immunosuppression from chemotherapy or chronic illness all raise the risk of the decay and infection that lead to toothaches.
What the Type of Pain Tells You
Not all toothaches feel the same, and the character of the pain is a useful clue about what’s going on.
Sharp, sudden pain triggered by cold drinks, sweet foods, or biting down usually points to a surface or structural problem: a cavity, a crack, enamel erosion, or exposed roots from gum recession. If the pain lasts only a few seconds and fades quickly, it’s likely early decay or general sensitivity.
Dull, throbbing pain that lingers or builds over time signals something deeper. This kind of ache is associated with advanced decay, infection, or chronic inflammation inside the tooth. If pain persists for more than 30 seconds after a trigger like hot or cold food, the nerve tissue is likely inflamed in a way that may not resolve on its own.
Pain that wakes you up at night is a particularly telling sign. It suggests irreversible damage to the pulp, the kind that typically requires professional treatment rather than watchful waiting. And if that pain comes with facial swelling, fever, a bad taste in your mouth, or pus along the gumline, infection has likely spread beyond the tooth itself and needs prompt attention.
When the Tooth Isn’t the Problem
Sometimes what feels like a toothache has nothing to do with your teeth. Sinus infections are a common culprit. The largest sinus cavities sit directly above the roots of your upper back teeth, and when those sinuses become inflamed, the pressure can produce convincing tooth pain. If the ache affects several upper teeth at once and coincides with congestion or facial pressure, sinusitis is a likely explanation.
Jaw joint disorders can also send pain into the teeth, as can tension headaches and, in rare cases, nerve conditions affecting the trigeminal nerve. If a dentist examines your teeth and finds nothing wrong, the next step is investigating these non-dental causes.
How Dentists Find the Source
Diagnosing a toothache involves more than looking inside your mouth. Dentists use a combination of visual examination, X-rays, and specific provocation tests to identify which tooth is responsible and how severe the damage is.
Cold tests are among the most common. A dentist applies a refrigerant spray or a small piece of dry ice to individual teeth and watches your response. A healthy tooth produces a brief, mild sensation that fades quickly. A tooth with inflamed pulp produces intense pain that lingers. A tooth that doesn’t respond at all may have nerve tissue that has already died.
Tapping on teeth (percussion testing) helps identify infections that have spread to the root tip or surrounding bone. Electric pulp testing sends a small current through the tooth to check whether the nerve is still functioning. In difficult cases where no test gives a clear answer, a dentist may prepare a tiny test cavity without anesthesia to see if you feel anything, though this is a last resort.
Treatment and What to Expect
Treatment depends entirely on the cause. A small cavity needs a filling. A cracked tooth may need a crown. Gum recession can be managed with desensitizing treatments or, in more advanced cases, grafting procedures.
When decay or damage reaches the pulp, root canal therapy is the standard treatment. The procedure removes the infected or inflamed tissue from inside the tooth, cleans the canal, and seals it. Root canals have a strong track record: the majority of patients see significant pain reduction, and about 56% of those who experience some lingering discomfort afterward improve without any additional treatment. Roughly 19% of patients develop persistent pain following the procedure, but even among that group, most continue to improve over the following years.
When infection has spread into the jawbone or surrounding tissue, forming an abscess, antibiotics and drainage may be necessary before any restorative work can begin. In cases where the tooth is too damaged to save, extraction followed by an implant or bridge is the final option.
Signs That Need Immediate Attention
Most toothaches develop gradually and can wait for a scheduled dental appointment. But certain symptoms indicate a more urgent situation. Swelling in the face, jaw, or gums that worsens or makes it hard to open your mouth suggests an infection that could spread to deeper tissues. Fever alongside tooth pain points to the same concern. Pus draining near the gumline, a persistent foul taste, and redness or warmth over the swollen area are all signs of active infection that benefits from prompt treatment rather than a wait-and-see approach.