Tooth Infection

In plain English

What tooth infection usually means

A tooth infection begins when bacteria reach a place the body cannot easily defend: the soft pulp inside the tooth, or the gum and bone around its root. The pulp sits in a rigid, sealed chamber, so once it is infected there is little room for swelling and little chance of it clearing unaided. The usual course is gradual. Sensitivity or a lingering ache becomes a throb that can keep you awake, the tooth turns tender to bite on, and a bad taste or a small pimple-like bump may appear on the gum. If it continues, pus collects at the root tip or in the gum, and swelling can move into the cheek, jaw or neck. Pain sometimes eases when the nerve dies, which does not mean the infection has gone. Because a tooth infection can spread to other parts of the body and become life-threatening, it is treated as urgent: see a dentist immediately or within 24 to 48 hours, and faster if there is swelling or fever. Only an exam can show where the infection sits and what is feeding it.

Untreated cavity reaching the pulp

Decay that works through the enamel and the dentin beneath it eventually opens a path to the pulp. This often follows a history of a visible hole, a dark spot, or sensitivity to sweets and cold that turned into a constant ache. How deep decay goes is judged on an x-ray, not by how the tooth looks.

Cracked or chipped tooth

A crack or chip can let bacteria in even when the tooth looks sound. Pain is often sharp on biting or on letting go, and may come and go for weeks before an infection settles in. Cracks are hard to see and do not always show on x-rays, so a dentist may use other tests.

Failed dental work

An old filling or crown that leaks at its edge, or an earlier root canal that did not fully heal, can let bacteria back in underneath. The tooth may have been quiet for years beforehand. Tenderness on biting or a gum bump that keeps returning near a treated tooth is worth reporting to a dentist.

Gum disease

Infection can also start in the gum instead of inside the tooth, in a deep pocket between the gum and the root. The gum is often swollen and sore beside one tooth, may ooze when pressed, and the tooth can feel slightly loose or as if it sits higher than its neighbors.

What a dentist does about it

A dentist usually starts with questions: when the pain began, what sets it off, whether you have noticed swelling, fever or a bad taste, and your medical history. The exam often includes tapping on teeth, pressing along the gum, testing how the tooth responds to cold, measuring the gum pockets, and an x-ray to look for a dark area around the root tip. Treatment aims to remove the source, not only quiet the symptoms. Depending on what is found, that can mean a root canal to clean out the inside of the tooth, draining the area, cleaning a deep gum pocket, or removing a tooth that cannot be saved. Antibiotics are sometimes prescribed when there are signs of spread, but they do not replace treating the tooth. Marked facial swelling may mean a referral to an oral surgeon or a hospital.

Until you can be seen

Nothing done at home treats a tooth infection, so these steps are only for comfort while you arrange to be seen within 24 to 48 hours. A warm salt water rinse can soothe the area but does not treat the infection. A cold compress on the cheek can ease swelling, and sleeping with your head raised often reduces throbbing. Over-the-counter pain relief can be taken as directed on the label; ask a pharmacist what suits you. Do not press on or try to open a gum bump. If you develop trouble breathing or swallowing, swelling spreading toward the eye or neck, or fever with facial swelling, call 911 or go to the ER instead of waiting for the appointment.

Note — Timing

When to See a Dentist

Table 1 — Possible causes

Possible Causes of Tooth Infection

1. 01Untreated cavity reaching the pulp
2. 02Cracked or chipped tooth
3. 03Failed dental work
4. 04Gum disease

Table 2 — Home remedies & self-care

Home Remedies & Self-Care

These may help manage symptoms temporarily while waiting for professional care.

• 01Warm salt water rinse for comfort (it does not treat the infection)
• 02Cold compress on cheek for swelling
• 03Over-the-counter pain relievers, taken as directed on the package label
• 04Keep head elevated when sleeping

Table 3 — Common treatments

Common Treatments for Tooth Infection

These dental procedures are commonly used to treat tooth infection.

Table 4 — Common questions

Frequently Asked Questions About Tooth Infection