My filling fell out and my tooth is black inside — what does it mean?

Seeing black inside a tooth after a filling falls out can be alarming — but in most cases it points to one of two things: staining left behind by an old silver filling, or active tooth decay. Both call for attention, but only one is a true clinical concern. Your dental provider can determine which is which with a simple exam and X-ray, and in most cases the tooth can be fully restored.

What you'll learn in this article:

• The black discoloration inside your tooth almost always means either harmless metal staining from an old silver filling or active decay, but an exam is the only way to know for certain.

• Active decay typically feels soft to the tongue, may cause sensitivity to sweets or cold and can advance quickly once a filling is gone.

• Leaving the exposed tooth untreated allows bacteria to cause additional damage, even when there's no noticeable discomfort.

• Most cases are treatable with a new filling or crown, especially when addressed promptly.

If you're unsure how serious your situation is, schedule an appointment with an Aspen Dental provider for a personalized evaluation.

What causes a tooth to look black inside?

Black or dark discoloration inside a tooth has a few possible explanations. The most common are amalgam staining and active decay. Less frequently, it signals that the nerve inside the tooth has been affected.

Is it old amalgam (silver) staining?

Silver amalgam fillings contain metal that can gradually stain the surrounding tooth over time, turning it gray, blue or black. When a silver filling falls out, that darkened tooth often becomes visible for the first time.

Amalgam staining by itself is harmless. The tooth is usually still structurally sound; it just looks darker because of years of contact with the filling. However, staining and decay can occur together in older fillings, so your dental provider will carefully examine the tooth to determine the cause.

Is it tooth decay?

Decay is the more common cause. Over time, bacteria can get under the edges of a filling and slowly break down the tooth underneath. As the decay spreads, it can turn the exposed area brown or black.¹

Active decay may feel soft or rough when you run your tongue over it. It can also cause a bad smell or sensitivity to sweet, cold or hot foods and drinks.²

Could the nerve be involved?

If decay has been spreading for a long time, it can eventually reach the pulp (the soft tissue at the center of the tooth that contains the nerve and blood vessels). Signs include deep, throbbing discomfort that comes and goes on its own and often gets worse at night.

This is less common when a filling has just fallen out, but it's more likely with older, larger or deeper fillings. An X-ray is the best way to see whether the decay has reached the nerve.

What to do while you wait for your appointment

Rinse with warm water after meals to help remove food from the exposed area. Avoid chewing on that side, and stay away from very hot, cold or sweet foods that trigger sensitivity. You can also use temporary filling material from most pharmacies to cover the opening and help reduce discomfort until your appointment.

Don't wait too long to have the tooth repaired. The tooth underneath a filling is softer than enamel and more vulnerable to decay. A tooth that needs only a simple filling today could require more extensive treatment if you wait.

What treatment might you need?

Your dental provider will examine the tooth and take X-rays before recommending any treatment. There are three likely options:

Will I just need a new filling?

If decay is limited and enough healthy tooth structure remains, a new filling is often all that's needed. Your provider removes the decay, cleans the area and places a new restoration.

Do I need a dental crown?

When significant tooth structure has been lost — common with older or larger fillings — a crown is often the more durable long-term option. A crown covers and protects the entire tooth, restoring its strength and shielding it from future damage.

Could I need a root canal?

If the nerve is infected, a root canal may be necessary. The procedure removes the infected pulp, cleans the tooth's interior and seals it — followed by a crown to protect the restored tooth.

When should you seek urgent care?

A filling that falls out and leaves a dark area behind usually isn't a dental emergency. But some symptoms mean you need care right away.

Seek care immediately if you have severe, constant throbbing that keeps you awake, swelling in your jaw or gums, a fever or trouble swallowing. These can be signs of a dental abscess, a serious infection that needs prompt treatment.

If you don't have these symptoms, schedule an appointment as soon as you can. Waiting a few days is usually okay, but waiting several weeks is not.

If your filling has fallen out, don't wait for symptoms to get worse. Schedule an appointment with your dental provider to have the tooth evaluated and find out what treatment, if any, is needed.

My filling fell out and my tooth is black inside — what does it mean? FAQs

Still have questions? Here are answers to some of the most common concerns about what it means when a filling falls out and the tooth underneath looks black.

Why did my filling fall out in the first place?

Fillings don't last forever. Most last 5 to 15 years, depending on the material, size and how much pressure the tooth handles. The most common cause is decay forming around the edges, which weakens the bond between the filling and the tooth until it comes loose. Everyday wear, teeth grinding and biting hard or sticky foods can also shorten a filling's lifespan.

Can I brush my teeth while waiting for my appointment?

Yes. Use a soft-bristled brush and gentle pressure around the exposed area. Keeping the tooth as clean as possible helps limit further bacterial buildup. Avoid pressing directly into the opening, but don't avoid the area entirely.

How long does treatment take?

It depends on the treatment. A new filling is usually done in under an hour. A crown typically needs two visits: one to prepare the tooth, another to place it, though same-day crowns are available at many dental providers. A root canal generally takes 60–90 minutes. Your provider can give you a specific estimate after the exam.

What will happen at my appointment?

Your dental provider will examine the tooth and take X-rays to see how much damage is present and whether the nerve has been affected. Then they'll explain your treatment options, which may include a new filling, a crown or a root canal, and answer any questions before treatment begins. If you've been using temporary filling material, let your provider know so they can remove it before the exam.

Sources

¹Mayo Clinic. "Cavities and Tooth Decay — Symptoms and Causes." https://www.mayoclinic.org/diseases-conditions/cavities/symptoms-causes/syc-20352892

²Cleveland Clinic. "Cavities (Tooth Decay): Symptoms, Causes & Treatment." https://my.clevelandclinic.org/health/diseases/10946-cavities