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What Dead Teeth Look Like On X-rays

Updated: Jan 4

Sometimes teeth can die without you knowing about it but one way to tell if you have a dead tooth is by how it looks on a dental x-ray. Non-vital teeth that are necrotic, have very distinct radiographic appearances which differentiates it from vital dentition.


Dead front tooth (discolored)
Dead front tooth (discolored)

We will show you four different clinical presentations of what it can look like on an x-ray. While we're at it we'll also go over other ways to tell if you have this condition and what you can or should do about it.


Signs of a dead tooth on x-ray

When vital teeth transition to being non-vital, it can do so quickly or slowly. Either of these paths will go through different stages of death and each one will have a distinct radiographic appearance. In other words, necrotic teeth can look different on x-rays depending on how far along its journey it is at.


Dead tooth stages and their radiographic appearance
Progression of x-ray appearances for dead teeth


Stages of slow death:

  1. Normal x-ray presentation

  2. Constricted or shrinking canal.

  3. Obliterated canal.


Stages of fast death:

  1. Normal x-ray presentation.

  2. Halo around the root tip.


We will show you what each of these stages look like on x-rays.


Halo around root tip

A tell-tale sign of a dead tooth on an x-ray is if you see a dark halo around the tip of the root. It will look like a big black ring that surrounds the apex of the tooth. If you see this big radiolucency at the tip, you can consider your tooth non-vital.


front-tooth-periapical-pathology - marked
Halo around root tip - outlined on x-ray

As an additional piece of information, that halo around the root tip is also an indication of a periapical abscess, meaning there is a large nerve infection. Essentially the cause of your tooth dying is because it succumbed to an abscess!


Constricted canal

A constricted canal that looks like it is shrinking on an x-ray is indicative of a dead tooth. The only reason why the tooth nerve would be disappearing would be if it was dying or already has died.


Constricted canal of dead front tooth x-ray
Constricted canal

Obliterated canals on x-ray - marked to show non-existence
Obliterated canals marked

In the two images above you can see that the tooth on the right has a MUCH smaller canal. The canals should look like a wide dark line that extends from the pulp chamber to the apex. However, in the necrotic front tooth on the right of the x-ray, you can only see a tiny sliver of the canal.


Obliterated canal

Teeth that have been dead for a very long time will have an obliterated canal on the x-ray. What this looks like is a tooth with a non-existent canal. Normally teeth should show a dark or black line that extends from the pulp chamber to the root tip. However, in this case, that black line will be missing from the x-ray!


Obliterated canals on x-ray
Obliterated canals

Obliterated canals on x-ray - marked to show non-existence
Obliterated canals marked

You may be wondering... where did the tooth nerve in the canal go? Well, it died.


Normal presentation

The very beginning stage of every non-vital tooth will actually look normal on an x-ray. The reason is because the changes on an x-ray takes time for it to show up. The halo around the root tip, the shrinking canal, and the obliterated canal all take weeks or even months for it to display itself on a radiograph.


Normal PA xray of upper front teeth with no diseases
PA x-ray of upper front teeth with no problems

Therefore, if something just happened to your tooth it may not be detectable on an x-ray right away. In these situations, not seeing any problems on the xray is NOT an indication of everything being okay.


 

Other signs of necrotic teeth

X-rays aren't the only way to tell that your tooth has died because there are plenty of other signs and symptoms.


Signs of a dead tooth:

  • Tooth discoloration. Necrotic teeth tend to discolor over time becoming darker and darker with each passing year. At first they look a tooth shade more yellow than the adjacent teeth but it eventually progresses to a grey and black color.

  • Excruciating pain. Typically the incidence which has caused it to die can be extremely painful. However, after the nerve fully passes away the tooth often becomes asymptomatic.

  • History of trauma. Teeth that have sustained trauma in the past should be monitored for any change in vitality. Not all of them will die immediately, some do so in a very slow manner and can take many years for it to finally croak.


necrotic tooth discolored
necrotic tooth discolored

Yes, the teeth will continue to get darker and darker because dead teeth changes colors.


 

Treatment

Dead teeth need two types of dental treatment, the first is for the non-vital nerve and the second is for cosmetics to alter its color.


Nerve treatment:

  • Root canal. The most conservative way to treat the nerve is with root canal therapy. Once the infected nerve has been removed, it will get filled in with gutta percha a root filling material. The benefit of this treatment is that it permits the tooth to be internally bleached later on.

  • Extraction. There are times where non-vital teeth cannot be restored with root canal treatment. If that is the case then it must be removed from the mouth.


Cosmetic treatment:

  • Teeth whitening. External teeth whitening or internal bleaching can be performed on the teeth to lighten the color. The latter bleaching treatment can only be done on root canal treated teeth.

  • Crowns. If whitening your teeth isn't sufficient to change the color of the tooth, you will need a crown to mask the color. Tooth will need to be prepared and shaved down in order to fit the tooth cap over it.

  • Veneers. A porcelain veneer is a viable option if the overall tooth structure is intact despite it being dead. However, a crown is a much more likely option.


Even if the tooth isn't hurting you, you will eventually seek out treatment on your own because the discoloration becomes difficult to ignore. It is a cosmetic nightmare.


Takeaway

A dead tooth can have multiple radiographic appearances.

  • Periapical radiolucency.

  • Constricted canal.

  • Obliterated canal.

  • Normal x-ray.


Last but not least, don't forget that teeth that have had root canals done on them are considered dead as well. If it no longer has a nerve it is 100% dead! That wraps up everything that our dentists in Long Island City have to say about this subject.


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About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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