Is My Tooth Infected? Signs You Shouldn't Ignore

Last Updated: October 12, 2026

Introduction

If you have a lasting toothache along with swelling, redness in your gums, a bad taste in your mouth, or a fever, your tooth may be infected. The American Dental Association lists those signs for an abscessed tooth, which is a pocket of pus that forms when infection builds at the root. Call a dentist right away, because a tooth infection will not clear up on its own.

What Is a Tooth Infection?

A tooth infection is usually described as an abscessed tooth. The ADA defines it as "an infection caused by tooth decay, periodontal disease, or a cracked tooth," and explains that when pus collects at the root tip in the jawbone, it forms a pocket called an abscess.

The American Association of Endodontists describes how this happens inside the tooth. The pulp, which is the soft tissue inside the tooth's root canal, dies and becomes inflamed. If that goes untreated, infection develops in or around the root.

How Do I Know If My Tooth Is Infected?

The ADA lists these signs of an abscessed tooth:

• Pain
  
• Swelling
  
• Redness in the gums
  
• A bad taste in the mouth
  
• Fever

The AAE adds that an aching mouth or jaw, pain while chewing, and swollen gums can all point to an abscessed tooth. The National Institute of Dental and Craniofacial Research notes that when a tooth becomes infected, an abscess can form and cause pain, facial swelling, and fever.

One detail matters more than any symptom list. The AAE says the infection "may or may not be painful." So the absence of a severe toothache does not rule out an infection, and a tooth that has stopped hurting is not necessarily a tooth that has healed.

What Causes a Tooth Infection?

According to the ADA, the three main causes are tooth decay, periodontal disease, and a cracked tooth. Each one gives bacteria a path to the inside of the tooth or to the tissue around its root.

NIDCR explains the decay side of this. Bacteria in the mouth turn sugars and starches into acid. The acid draws minerals out of the enamel, and the enamel eventually breaks down and forms a cavity. Decay that is left alone can lead to pain, infection, and tooth loss.

If you want the longer version of how an infection builds, see our guide to the stages of a tooth abscess.

Will a Tooth Infection Go Away on Its Own?

No. An abscess needs treatment, and the ADA is direct about what happens otherwise: "If the abscess is not treated, it can lead to a serious infection in the jaw bone, teeth, and surrounding tissues." Our article on what happens if a tooth infection reaches the jaw covers that progression in more detail.

The AAE puts the same point in practical terms. Any ongoing symptoms should be seen by a dentist or an endodontist, who specializes in treating infected teeth and pulp. Waiting does not resolve the cause.

When Should I See a Dentist?

The ADA's guidance on dental symptoms is that a toothache should be evaluated by a dentist right away, which also helps prevent the tooth from dying. Call your dentist if you notice any of the signs above, and do not wait for the pain or swelling to get worse.

When Is a Tooth Infection an Emergency?

An infection that spreads beyond the tooth is treated as urgent. The ADA's clinical guidance on dental pain and swelling says patients "should be referred for urgent evaluation if their condition worsens, they develop a deep space infection, or sepsis is suspected."

In plain terms, get care the same day if your swelling is spreading, your pain is getting worse quickly, or you feel unwell with a fever. The ADA also advises that if your dental office is closed during an emergency, go to a local emergency room.

How Do Dentists Treat an Infected Tooth?

Treatment depends on the cause and how severe the infection is. The ADA lists these options:

• Antibiotics, to target the bacteria causing the infection
  
• Drainage of the infection
  
• Cleaning the space between the tooth and the gum, when gum disease is the cause
  
• Root canal treatment, when decay or a cracked tooth is the cause

The AAE describes what a root canal involves. The bacteria are removed from the canals, the canals are cleaned and shaped, and the space is sealed. A crown or other restoration is placed afterward.

One point surprises many patients: antibiotics are not the main treatment. The ADA's guideline states that "antibiotics are not needed for the urgent management of most dental pain and intraoral swelling" in healthy adults when dental treatment is available. AAE guidance agrees that for a localized abscess, antibiotics added on top of proper cleaning and drainage are not effective at preventing or easing symptoms. They are reserved for cases with signs of systemic involvement, such as fever, malaise, or spreading infection, and for patients who are immunocompromised.

What Can I Do Before My Appointment?

These steps may ease discomfort while you wait. None of them treats the infection, so keep your appointment either way.

• Rinse your mouth with warm water to clean it out, as the ADA advises for a toothache
  
• Use floss gently to remove any trapped food
  
• Apply a cold compress to the outside of your face to help with swelling
  
• Do not place pain medication directly against the tooth or gums, because the ADA warns it can burn gum tissue

If you are unsure what pain reliever is appropriate for you, ask your dentist or pharmacist.

How Alpine Dental Helps

Alpine Dental provides root canal treatment and dental emergency care at our Lakewood and Jackson, NJ offices. If you think a tooth may be infected, call and describe your symptoms so the team can advise you on next steps. Book an appointment with us. Same-day or after-hours appointments are available for suspected infections, whether root canals are performed in-house or referred out.

Wondering "is my tooth infected?" is worth acting on rather than watching. Lasting pain, swelling, gum redness, a bad taste, or a fever all deserve an exam, and an infected tooth will not resolve without treatment.

Call Alpine Dental at (732) 934-1888 or contact us online to have your symptoms evaluated.

Frequently Asked Questions

Can a tooth infection heal on its own?

No. An abscess needs dental treatment to remove the source of the infection. The ADA warns that an untreated abscess can lead to serious infection in the jawbone, teeth, and surrounding tissues.

Does an infected tooth always hurt?

No. The AAE states that an abscessed tooth may or may not be painful. Swelling, redness in the gums, a bad taste, or a fever can appear without severe pain, and pain that fades does not mean the infection is gone.

Do I need antibiotics for an infected tooth?

Usually not on their own. The ADA guideline says antibiotics are not needed for urgent management of most dental pain and swelling in healthy adults when dental treatment is available. AAE guidance reserves them for signs of systemic involvement, such as fever or spreading infection, and for patients who are immunocompromised. Your dentist decides based on your exam.

How quickly should I see a dentist if I think my tooth is infected?

Right away. The ADA advises that a toothache be evaluated by a dentist promptly. If your condition worsens or you suspect the infection is spreading, the ADA guideline calls for urgent evaluation that day.

Can a tooth infection affect the rest of my body?

It can. The ADA guideline names deep space infection and suspected sepsis as reasons for urgent evaluation, and NIDCR notes that an infected tooth can cause facial swelling and fever. That is why spreading swelling or feeling unwell is treated as an emergency rather than a wait-and-see situation.

SOURCES:

• https://www.mouthhealthy.org/all-topics-a-z/abscess
• https://www.mouthhealthy.org/top-dental-symptoms
• https://www.mouthhealthy.org/dental-care/dental-emergencies/
• https://www.aae.org/patients/dental-symptoms/abscessed-teeth/
• https://www.aae.org/uploadedfiles/clinical_resources/guidelines_and_position_statements/aae_systemic-antibiotics.pdf
• https://www.cdc.gov/antibiotic-use/media/pdfs/ada-treatment-guidelines-508.pdf
• https://www.nidcr.nih.gov/health-info/tooth-decay
• https://www.mayoclinic.org/diseases-conditions/tooth-abscess/symptoms-causes/syc-20350901