A dead tooth is one whose inner tissue, called the pulp, has permanently lost its blood supply and nerve function. The pulp sits in a small chamber at the center of every tooth, containing blood vessels that keep it nourished and nerves that let you feel temperature and pressure. When that tissue dies, the tooth is no longer alive, even though it can remain in your jaw for months or years. Dentists call this pulp necrosis.
How a Tooth Dies
Every tooth looks solid from the outside, but it has a living core. The pulp receives blood through tiny vessels that enter at the root tip. If bacteria reach the pulp or that blood supply gets cut off, the tissue begins to break down. This can happen in two main ways.
The first is decay. An untreated cavity gradually eats through enamel and the layer beneath it, eventually opening a path for bacteria to invade the pulp chamber. Cracks in a tooth or worn-down enamel from grinding or aggressive brushing can create the same entry point. Once bacteria colonize the pulp, inflammation sets in. At first the tissue tries to fight back, a stage called reversible pulpitis. If the damage is caught early, a filling can seal the tooth and the pulp recovers. But if inflammation progresses, it becomes irreversible. The tissue swells inside a rigid, enclosed space with no room to expand, choking off its own blood supply until the nerve and soft tissue die.
The second path is trauma. A blow to the face, a sports injury, or even a hard bite on something unexpected can sever the blood vessels at the root tip. Without blood flow, the pulp starves and dies, sometimes without any visible crack or cavity on the surface.
Signs and Symptoms
Pain is often the first clue, but it can be misleading because it changes over time. While the pulp is still inflamed but alive, you may notice a lingering sensitivity to hot or cold that lasts more than a few seconds, along with throbbing or aching pain. This is the irreversible pulpitis stage, and it can be intense.
Then, paradoxically, the pain may stop. Once the nerve tissue dies completely, the tooth loses its ability to sense temperature, sweets, or pressure. Some people interpret this relief as the problem fixing itself. It hasn’t. The infection is still there; the alarm system just went silent.
Color change is the other hallmark. A dead tooth may turn yellow, light brown, gray, or black, looking almost bruised compared to the teeth around it. This discoloration deepens over time as the internal tissue continues to break down. It tends to be most noticeable on front teeth.
Pain can also return later if infection spreads beyond the root tip into the surrounding bone, forming an abscess. At that point you might experience swelling, a bad taste in your mouth, or a dull, deep ache in the jaw.
How Dentists Confirm It
Your dentist will typically use at least two tests to confirm the pulp is dead, since a single test can sometimes give a misleading result.
- Cold test: A refrigerant spray is applied to the tooth. A healthy tooth responds with a brief, sharp sensation. A dead tooth feels nothing.
- Electric pulp test: A small device sends a mild electrical current through the tooth. If the nerve fibers are alive, you’ll feel a tingling or buzzing. No sensation points to necrosis.
- Heat test: Warm material is placed on the tooth. This test can activate deeper nerve fibers that the cold test misses, making it especially useful in ambiguous cases.
- X-rays: Radiographs reveal the size of the pulp chamber and whether infection has started eating into the bone around the root tip. A dark halo at the root tip on an X-ray is a telltale sign of a periapical abscess.
False negatives can happen. Teeth with heavily calcified canals, recent trauma, or roots that haven’t fully formed may not respond to testing even when some living tissue remains. That’s why dentists cross-reference multiple tests before making a diagnosis.
What Happens If You Leave It Alone
A dead tooth doesn’t heal on its own. The decaying pulp tissue becomes a breeding ground for bacteria, and because there’s no blood flow to deliver immune cells, the infection can only grow. It typically spreads through the root tip into the jawbone, forming a periapical abscess: a pocket of pus that causes swelling and pain.
Left untreated, that infection can spread further into the jaw and eventually into other areas of the head and neck. In rare but serious cases, the bacteria enter the bloodstream and cause sepsis. Bone loss in the jaw is another risk. When infection erodes the bone around a tooth root, that bone doesn’t grow back without intervention, sometimes requiring a bone graft if the tooth is eventually removed.
There’s also a less common complication called internal root resorption, where the body’s own cells begin dissolving the tooth from the inside out. This typically happens when part of the pulp is dead and part is still inflamed. The inflammation triggers specialized cells that eat away at the root structure, weakening the tooth until treatment becomes more difficult or impossible.
Root Canal Treatment
A root canal is the standard treatment for a dead tooth when the surrounding structure is still strong enough to save. The procedure removes all the dead and infected pulp tissue from inside the tooth, cleans and disinfects the canal system, then fills and seals the space. A crown is usually placed on top afterward to protect the remaining tooth structure.
Success rates are high. A large study tracking over 800 treated teeth found that root canals on teeth with dead pulps succeeded about 89.5% of the time when no bone infection had developed. When bone infection was already present, the success rate dropped to around 83%, still favorable but a clear argument for not waiting. Teeth with living pulps had the highest success rate at about 91.5%, reinforcing that earlier treatment tends to produce better outcomes.
The major advantage of a root canal is keeping your natural tooth. Even without a living pulp, the outer tooth structure remains functional for chewing and maintains the spacing of your other teeth.
When Extraction Is Necessary
If the tooth is too damaged, cracked below the gumline, or if bone loss is severe, extraction may be the only option. Removing the tooth eliminates the source of infection, but it creates a gap that can cause neighboring teeth to shift over time, affecting your bite and your ability to chew properly.
Replacing an extracted tooth typically means a dental implant or bridge, which requires additional visits and procedures. If significant bone was lost to infection, a bone graft may be needed before an implant can be placed. For most people, this path ends up being more expensive and time-intensive than a root canal, which is why saving the tooth is generally preferred when it’s structurally feasible.
Discoloration After Treatment
Even after a successful root canal, a dead tooth can remain darker than its neighbors. The breakdown products from the old pulp tissue stain the tooth from the inside. Internal bleaching, where a whitening agent is placed inside the tooth during or after root canal treatment, can lighten the discoloration. A porcelain crown or veneer is another option that covers the tooth entirely and matches the surrounding shade. Front teeth are the most common candidates for cosmetic correction since the color difference is most visible there.