An infected tooth typically announces itself with a persistent, throbbing pain that doesn’t fade with time and often spreads into your jaw, ear, or neck. Unlike a regular toothache from sensitivity or a minor cavity, an infection produces pain that intensifies, sometimes wakes you at night, and may come with visible swelling or a bad taste in your mouth. Knowing what to look for helps you act before the infection worsens.
The Most Common Signs of a Tooth Infection
The hallmark symptom is a severe, constant, throbbing toothache. This isn’t the occasional twinge you get from biting into something cold. Infection pain tends to be relentless, and it radiates. You might feel it in your jawbone, up through your ear, or down into your neck, even though the problem is a single tooth.
Beyond the pain, watch for these signs:
- Sensitivity that lingers. Hot and cold foods or drinks trigger sharp discomfort that sticks around well after you stop eating or drinking.
- Pain when biting or chewing. Pressure on the affected tooth causes a distinct ache, sometimes sharp enough to make you avoid chewing on that side entirely.
- Swelling in your face, cheek, or neck. This can range from a subtle puffiness near the jawline to obvious swelling that’s visible to others.
- Swollen, tender lymph nodes. The glands under your jaw or along your neck may feel sore and enlarged as your immune system responds to the infection.
- Fever. Even a low-grade fever alongside tooth pain suggests infection rather than simple sensitivity.
- Bad breath or a foul taste. Infection produces bacteria and pus, which can create a persistent unpleasant odor or taste that brushing doesn’t fix.
- A sudden gush of salty, bad-tasting fluid. If the abscess ruptures on its own, you’ll get a rush of foul-tasting liquid in your mouth. The pain often drops immediately afterward, but the infection is still there and still needs treatment.
What a Gum Boil Means
One of the most visible clues is a small bump on your gum near the affected tooth, sometimes called a gum boil. It looks like a smooth, rounded pimple on the gum tissue and can be yellow, red, or pink. It’s soft to the touch, and pressing on it lightly may produce drainage of pus.
This bump is the exit point of a draining infection underneath. It forms because the infection has created a channel from the tooth root or gum pocket up to the surface. The bump itself isn’t the problem. It’s a signal that a deeper abscess exists. Removing or draining just the bump won’t resolve anything, because the source of infection remains at the root or in the surrounding gum tissue.
Two Types of Tooth Infections
Not all tooth infections start in the same place, and knowing the difference can help you describe your symptoms to a dentist.
A periapical abscess is the most common type. It starts inside the tooth, near the nerve, and forms at the root tip. This happens when bacteria reach the inner tissue through decay, a crack, or a chip in the enamel. If left alone, the infection travels down the root and creates a pocket of pus at the tip. The pain is usually centered on a specific tooth that may have a history of cavities or damage.
A periodontal abscess starts in the gum tissue alongside the root rather than inside the tooth itself. These are more closely tied to gum disease or injuries to the gum. You’re more likely to notice swelling or tenderness in the gum tissue rather than deep inside the tooth. These infections create pockets where bacteria thrive, and they can damage the bone and tissue that hold teeth in place.
How a Dentist Confirms the Infection
Your dentist won’t rely only on your description of pain. Several tests help pinpoint whether a tooth is truly infected and how far the damage extends.
Tapping on the tooth (percussion testing) checks for inflammation at the root. A tooth with an active infection at its base will produce a noticeably different pain response compared to healthy neighboring teeth. Thermal testing applies heat or cold to the tooth to see if the nerve inside is still responding normally. A tooth that doesn’t react at all may have a dead nerve, which is a strong indicator that infection has killed the tissue inside. However, the absence of a heat response alone isn’t definitive, so dentists combine multiple tests.
X-rays are the most revealing tool. They show dark areas around the root tip that indicate bone loss from infection, and they can reveal deep decay or damage that isn’t visible from the surface. In some cases, a 3D scan provides a more detailed view of how far the infection has spread into surrounding bone.
Managing Pain Before Your Appointment
If you can’t get to a dentist immediately, combining ibuprofen and acetaminophen is the most effective over-the-counter approach for dental pain. These two medications work through different pathways and are safe to take together. A common recommendation is 400 to 600 mg of ibuprofen every six hours alongside 500 to 650 mg of acetaminophen every six hours. Keep your total acetaminophen from all sources below 3,000 mg per day.
Saltwater rinses (half a teaspoon of salt in eight ounces of warm water) can help draw some of the infection toward the surface and temporarily reduce discomfort. These measures buy you time, but they cannot clear the infection. Antibiotics alone won’t resolve it either, because the bacteria are sheltered inside an enclosed pocket of pus that medication can’t fully penetrate. The abscess needs to be physically drained or the source of infection removed.
What Treatment Looks Like
For a periapical abscess, a root canal is the standard treatment to save the tooth. The dentist removes the infected tissue from inside the tooth, cleans and disinfects the internal canals, then seals them. Success rates for root canal therapy reach up to 97%, and when performed by a specialist, that number climbs to about 98%. If the tooth is too damaged to save, extraction is the alternative, followed by options like an implant or bridge to fill the gap. Implants and root canal-treated teeth have comparable long-term success rates, around 94% to 95%.
For a periodontal abscess, the dentist drains the infection and cleans the pocket between the tooth and gum. You may need a deeper cleaning procedure to remove bacteria and tartar from beneath the gum line. If gum disease is the underlying cause, ongoing management will be part of your treatment plan to prevent recurrence.
When a Tooth Infection Becomes Dangerous
Most tooth infections are painful but manageable with timely dental care. In rare cases, though, the infection spreads beyond the tooth into the soft tissues of the floor of the mouth and neck. This condition, called Ludwig’s angina, is a medical emergency. It can develop suddenly and cause rapid swelling under the jaw and tongue, making it difficult to breathe or swallow. The tongue may push forward or swell, and speaking can become slurred.
The complications of untreated spreading infection are severe: airway blockage, infection spreading into the chest cavity, and sepsis, which is a life-threatening immune response that can cause organ failure and dangerously low blood pressure.
Go to an emergency room if you experience difficulty breathing or swallowing, severe pain that keeps getting worse despite medication, swelling that spreads to your neck or under your jaw, or a high fever with visible facial swelling. These signs mean the infection has moved beyond what a routine dental visit can handle.