Dental Crown Infection: Signs, Causes and What Happens Next

Individual results vary based on the patient’s oral health, anatomy, and treatment plan. This content is for general informational purposes and does not substitute for an in-person evaluation by a licensed dentist.

Quick answer: Yes, a tooth under a crown can become infected. Bacteria can reach the tooth through decay at the crown’s edge, a crack, or a gap from a poor fit. Common signs include lingering or throbbing pain, gum swelling or a pimple-like bump near the crown, a bad taste, and pain when biting. A dentist needs to examine the tooth, usually with an X-ray, to confirm it.

A crown covers a tooth, but it doesn’t seal it off from everything forever. The tooth underneath is still living tissue (or, after a root canal, still anchored in living gum and bone), and it can develop problems like any other tooth. The good news is that many crown infections cause warning signs, and catching them early may mean simpler treatment.

Can a Tooth Get Infected Under a Crown?

It can. A crown protects the visible part of a tooth, but bacteria can still reach the tooth in a few ways:

• Decay at the margin. The edge where the crown meets the tooth is a spot plaque likes to collect. If decay starts there, it can work its way under the crown.
• Cracks or wear. A cracked crown, or a crack in the tooth beneath it, can let bacteria in.
• A crown that no longer fits well. Cement can wash out over time, or a crown may loosen, leaving a small gap.
• A deep problem that was already there. If the nerve inside the tooth was already irritated or damaged before the crown went on, it can become infected later.

Teeth that have had a root canal can also develop an infection later, for example if a canal wasn’t fully sealed or new decay reaches the root. That’s why a crowned tooth still needs regular checkups and X-rays.

Signs and Symptoms of an Infected Crown

Symptoms vary from person to person, and some infections cause very little pain at first. Signs worth paying attention to include:

• Pain around the crowned tooth that throbs, lingers, or keeps coming back
• Pain when you bite down or chew on that side
• Sensitivity to hot or cold that lasts after the food or drink is gone
• Red, swollen, or tender gums around the crown
• A small pimple-like bump on the gum (sometimes called a gum boil or fistula), which may drain
• A bad taste or bad breath that doesn’t go away with brushing
• Swelling in the cheek or jaw near the tooth

None of these confirms an infection on its own. They’re signs that the tooth should be checked.

What Does an Infected Crown Look Like?

From the outside, the crown itself usually looks the same. The changes tend to show in the gum around it. You might notice redness or puffiness along the gum line, a shiny swollen area, or a small raised bump that sometimes releases pus. Some people see a dark line at the edge of the crown. That can simply be the edge of an older metal-based crown showing through, but it can also be decay, so it’s worth having a dentist look.

Many infections can’t be seen at all without an X-ray. An abscess at the tip of the root, for instance, often shows up only on imaging.

Is Some Pain After a New Crown Normal?

Some tenderness or mild sensitivity for a few days after a crown is placed is common. The tooth and gum have been worked on, and your bite may need a little time to settle.

What’s less typical is pain that gets worse instead of better, pain that wakes you up, swelling, or a bite that feels “high” and makes the tooth sore every time you close. A crown that sits slightly too high can bruise the ligament around the tooth, and that’s usually a quick adjustment. Pain that lingers or grows, though, should be checked instead of waited out.

Other Crown Problems That Can Feel Like an Infection

Not every sore crown is infected. A dentist will also look for:

• Gum irritation from the crown procedure itself, which usually settles as the gum heals
• A fractured crown or tooth, which can cause sharp pain on biting
• A crown that doesn’t fit correctly, which can trap food and irritate the gum
• Grinding or clenching, which can make crowned teeth ache

How Dentists Treat an Infected Crown

Treatment depends on what the exam and X-rays show, so the right option is decided chair-side, not in advance. Common approaches include:

• Root canal treatment. If the nerve inside the tooth is infected, a dentist may be able to treat it through an opening made in the crown, then seal that opening. Sometimes the crown needs to be replaced afterward.
• Retreating an older root canal when a previously treated tooth becomes infected again.
• Replacing the crown if decay at the edge or a poor fit is the source of the problem.
• Extraction if the tooth can’t be saved, followed by a discussion of replacement options.

Antibiotics may be part of care in some cases, but they usually don’t fix the source of a dental infection on their own. The tooth itself generally needs treatment.

When It’s Urgent

Go to an emergency room or call 911 if dental pain comes with facial swelling and a fever, swelling that spreads toward your eye or down your neck, or any trouble breathing or swallowing. Those signs can mean an infection is spreading and needs urgent medical care.

For pain, gum swelling, or a bump near a crown without those red flags, call your dentist and ask to be seen soon. Infections don’t clear up on their own, and earlier treatment usually keeps more options open.

How to Lower the Risk

You can’t control every factor, but a few habits help protect crowned teeth: brush twice a day with attention to the gum line, clean between teeth daily, keep your regular checkups so the crown edges and the bone around the root can be checked on X-rays, and mention any change in how a crown feels or fits. If you grind your teeth, ask whether a night guard makes sense for you.

Frequently Asked Questions

Can a leaking crown make you sick?

A leaking or poorly sealed crown can allow decay and infection in the tooth underneath. Most of the time that stays a dental problem, but an untreated dental infection can spread, which is why swelling, fever, or feeling unwell alongside tooth pain should be taken seriously.

Can an infected tooth under a crown heal on its own?

A dental infection generally doesn’t resolve on its own. Symptoms can quiet down for a while, but the source usually needs treatment by a dentist.

Does the crown have to come off to treat an infection?

Not necessarily. A dentist can sometimes treat the tooth through the crown and then seal it. Whether the crown can stay depends on its condition and what caused the problem.

How long does a dental crown last?

Crowns can last many years with good care, but how long depends on the material, your bite, grinding habits, and how well the tooth and gums are kept clean.

If something doesn’t feel right with a crowned tooth, our team at Elements Dental Spa & Aesthetics can take a look. Learn more about crowns and bridges or our emergency dental care, or contact our Baton Rouge office to schedule a visit.

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