Dead tooth: symptoms, why it darkens, whether it needs treatment and whether it can be whitened

What is a dead tooth?

A dead tooth is a tooth whose pulp, the living tissue with blood vessels and nerves inside the tooth, has died. The American Association of Endodontists (AAE) defines pulp necrosis as a diagnostic category meaning the death of the pulp, in which the tooth usually does not respond to vitality tests.

A dead tooth still sits in the bone and may look ordinary, but without a living pulp it cannot defend itself against bacteria, which travel through the root canals to the bone around the root tip. There, inflammation of the periapical tissues develops, and it is sometimes visible only on an X-ray. How a tooth is built and what happens in the canals is described in the article on root canal treatment under a microscope.

What are the symptoms of a dead tooth?

The symptoms of a dead tooth are often subtle, and some people have no complaints at all. According to AAE terminology, asymptomatic inflammation at the root tip shows on an X-ray as a dark area, while a chronic abscess builds up slowly, with little or no discomfort, and from time to time drains pus through a sinus tract on the gum.

The list brings together the signs that most often lead to the diagnosis. It is a synthesis of AAE and IADT guidance rather than a single official list, and none of these signs on its own settles whether the pulp has died.

• A grey, brown or darker colour of one tooth compared with its neighbours.
• No response of the tooth to cold or to an electric test at the surgery.
• A dark area at the root tip on an X-ray.
• Swelling, an abscess or a small pimple on the gum by the tooth, which is the opening of a sinus tract.
• Sometimes pain on biting or when the tooth is tapped.

Dark tooth: when does a change of colour mean a dead pulp?

A dark tooth most often means a dead pulp when a single tooth is discoloured and there has been an injury or deep decay in the past. When all the teeth turn yellow or grey, the cause usually lies elsewhere, for example in staining from coffee and tea or in natural changes with age.

After a recent injury to a permanent tooth, the test result can be misleading. The 2020 IADT guidelines stress that no response to a vitality test in an injured tooth does not settle that the pulp has died, because the response often returns; that is why the dentist waits and repeats the test at later check-ups.

Why does a tooth die?

A tooth most often dies for one of two reasons: deep decay that has reached the pulp, or an injury that has cut off the blood supply to the tooth. In the first case the pulp usually becomes inflamed first, which hurts, and then dies, and the pain may ease, which is easy to mistake for an improvement.

After an injury, pulp necrosis is the most common complication. In a study of 889 injured permanent teeth (Dental Traumatology, 2010), it occurred in 26.9% of them. The risk depends on the type of injury and tends to be higher when the tooth has been displaced, which is why follow-up visits are recommended after an injury, even if the tooth does not hurt.

Does a dead tooth need treatment if it does not hurt?

A dead tooth needs treatment even when it does not hurt. The 2023 S3 guideline of the European Society of Endodontology (ESE) suggests carrying out root canal treatment of teeth with a dead pulp as soon as the diagnosis is confirmed, and calls it the gold standard for teeth with fully formed roots.

No pain does not mean no disease: a dead pulp does not grow back, and the infection in the canals can slowly destroy the bone by the root and at any moment turn into an acute abscess. Root canal treatment removes this source of infection and makes it possible to keep your own tooth.

The alternative is extraction, but that raises the question of how to fill the gap: with an implant, a bridge or a denture. The decision depends on how much of the tooth is left and on the condition of the bone, and it is made after an examination and an X-ray.

How is a dead tooth treated?

A dead tooth is treated with root canal treatment and then rebuilt so that it can withstand chewing. The details of the procedure under a microscope are described in a separate article; here are the main stages in brief.

A tooth after root canal treatment is more prone to fracture. In the study by Aquilino and Caplan (2002, 203 teeth), root-treated teeth without a crown were lost 6 times as often as teeth with a crown. Whether a filling is enough, or an onlay or a crown is needed, depends on how many of the tooth’s walls remain.

• Diagnosis: vitality tests, an intraoral X-ray and, when the picture is unclear, a CBCT scan.
• Local anaesthesia when needed, and isolation of the tooth with a rubber sheet (rubber dam).
• Cleaning and disinfecting the canals along their whole length, then sealing them tightly.
• Rebuilding the crown of the tooth: a filling, an onlay or a crown, depending on the loss of tissue.
• A follow-up X-ray, which shows whether the change at the root is healing.

Can a dead tooth be whitened?

A dead tooth can be lightened by internal whitening, carried out from inside the tooth after root canal treatment is complete. According to a review in the Journal of Endodontics (2008), the root filling is first sealed at the level of the neck of the tooth, and then a whitening agent is placed in the pulp chamber and replaced every 3 to 7 days.

In a series of 255 teeth (Australian Dental Journal, 2009), the change of colour was rated good in 87.1% and acceptable in 12.9%. The method is not free of risk, however: in an older study (1994), with 30% hydrogen peroxide and heat, cervical resorption occurred in 4 of 204 teeth, all of them after an injury.

Tray or lamp whitening is planned for living teeth, while in a single dead tooth the discolouration lies inside, which is why it is lightened from the inside. When the lightening is not enough, the tooth can be covered with a veneer or a crown; the table sets out these options.

How much does treating a dead tooth cost, and what does the NFZ cover?

The cost of treating a dead tooth depends on the number of canals, the number of visits and the type of restoration. Front teeth, which most often darken after an injury, usually have one canal, and molars three or four.

In the clinic’s price list, the total cost of single-session root canal treatment under a microscope for a tooth with one canal is 1 650 zł, the item “Odbudowa korony zęba martwego” (rebuilding the crown of a dead tooth) 600 zł, an all-ceramic veneer 3 000 zł and a full-zirconia crown 3 000 zł. The final scope and cost are agreed after the examination, and prices may change.

On the NFZ (Poland’s National Health Fund), adults have root canal treatment only of incisors and canines, that is teeth 1 to 3, while children and young people up to 18 and women who are pregnant or in the postnatal period have it for all teeth. Whitening, crowns and veneers are not among the services funded by the NFZ. Legal position as of 12 October 2026.

How it works at DentalBlue

At DentalBlue in Białystok, root canal treatment and root canal retreatment are carried out under a microscope. The images needed to diagnose a dead tooth, from an intraoral X-ray to a CBCT scan, are taken in the clinic’s own radiology unit. At a visit without pain, which includes a panoramic X-ray, a consultation and an examination, the patient receives a written treatment plan with the prices of each stage; in the price list this visit costs 300 zł. The clinic makes crowns and veneers as part of its prosthodontics and cosmetic dentistry.