I love my cone beam so much I want to kiss it. This machine has revolutionized the way that I use scans & X-rays for diagnostics and is a total game-changer for my endodontics practice. I was first introduced to the CBCT (cone beam computerized tomography) in 2009 at an endodontic CE event, but since I had just opened my practice, I didn’t have the funds to think about purchasing one.
Then 2012 came, and things were looking up. I finally pulled the trigger and bought one — and it is, hands down, the best thing I ever did for my practice. The cone beam has so many different applications, including:
- Facilitating early diagnosis and early detection of disease
- Revealing the true etiology of root canal failure
- Serving as a communication and patient education tool, leading to increased case acceptance
- Helping determine true lesion size and assisting in follow-up
- Aiding in the location of hard-to-find canals, especially the MB2 in maxillary molars
This machine is so powerful, but it does have limitations. Even with all its advantages, there is one thing that cone beam imaging can’t do. It can’t routinely detect a crack. This limitation is one that many general dentists don’t quite understand. I hear so many referring dentists tell their patients that they need a scan in order to see the crack, which then leads to patient frustration when an endodontist can’t deliver that information. They wonder why their dentist told them that in the first place! Be careful what you say to your patients, because sometimes it can be misleading.
I never promise a patient that I am going to see a crack on the cone beam, because this simply isn’t why I order a cone beam. Let me show you an example so you see what I mean.
A patient had a previous root canal and a draining buccal sinus tract. The sinus tract was traced to the furcation. Her diagnosis was Previously Treated Tooth and Chronic Apical Abscess. The root canal (done by another professional) looked like it was done really well, but the tooth was never restored with a crown.
A CBCT was obtained and here are some snapshots from the scan:
This image clearly shows the furcal breakdown and the lateral bone breakdown to the distal root.
The axial view below is usually the most helpful view when trying to make this evaluation.
Let me ask you this: can you visualize the fracture in the image? If so, shout it out right now, and let’s see if you are right! The answer is below.
When you are interpreting a CBCT, be careful about false positives that are actually artifact. When a tooth has a radiopaque material in or near it (i.e. gutta percha or an implant), watch out for scatter, beam hardening or reconstruction artifact. If you look at the axial slice again, you will see several black lines that look like cracks, but are actually nothing at all!
However, this tooth is cracked. When I send a tooth for an extraction, I request the tooth back so I can correlate the findings back to my cone beam. Here is what the tooth looked like in my hand:
From these images, you can clearly see the crack along the distal root that starts on the distal marginal ridge and goes all the way down to the apex. This crack is huge, and it never showed up on the cone beam!
So here is a little trick that may help: instead of looking for an actual fracture line on the cone beam, look for patterns of bone loss instead.
The bone loss adjacent to the distal root is what you SHOULD be looking for, and not the line itself. For more info on how to do this, click here for a must-read article.
I have seen some teeth where their fractures can be detected on the CBCT, but they are the exception to the rule. Generally speaking, if you can see the fracture on the cone beam, you can usually see it on the periapical radiograph, too.
I wish I could say that the CBCT could detect cracks and fractures in addition to its many other uses. My job would be so much simpler if that was the case!
At the end of the day, I’d encourage you to be careful what you say to your patients, and let them know what they can and can’t expect from the cone beam. The better your understanding of CBCT, the better you’ll understand the capabilities and limitations of this near-magical machine — and the better care you’ll be able to provide to your patients.
-Sonia
Really informative article! Thanks for this explanation. It can truly help my patients have realistic expectations.
Thank you Rebekkah – it’s all about the patient!
Best,Sonia
I think many people are misled about this. Thanks for your explanation.
Meena – I always appreciate your insight! Thanks for following-
– Sonia
Fantastic, very succinct and useful information!
Well written!
Love the work you on it!
Thank you Ernest! I appreciate you following along. Stay tuned for more!
-Sonia
Great information! Thanks for your images and clear explanations.
Thanks for reading – and stay tuned for more!
-Sonia
Amazing Dr Sonia. Quite a enough information.
Thank you!
-Sonia
Too good.. confusion cleared so clearly ..👍
Very nicely investigated
Thank you so much!
-Sonia
Very interesting as I feel I have another racked tooth but dentist cannot detect; it is hurting with hot/cold and sometimes eating; its full of old fillings…. do you think that some time in the future someone will “invent” a way to detect a crack/fracture ? I would like this tooth extracted before it gets worse and I have to go on an antibiotic as allergic to most… as this happened to another tooth years ago. Thanks for the information . A patient
If you happen to find the technology to detect cracks, please let me know because I would invest in it. Maybe you should consider just crowning the teeth that are showing signs of cracks so that you can prevent a split tooth. I would ask your provider these questions if you need more clarification.
Dr. Chopra
I went to a dentist (CBCT scan) for this exact reason, possible cracked tooth and could their 3D machine see it. 2 weeks and I haven’t heard back from them. The tooth is #18 and it has had a root canal and crown but I still have sensation. Not pain so much but more irritation when I bite or brush it. I’m at a loss on what can be done. The original dentist and endodontist have looked and both are stumped.
Angie,
I am sorry that you are having this problem. I would request that you have your tooth retreated. The same thing happened to my tooth and I retreated it and it now feels better. Ask your provider if it is an option for you. Please keep in mind, I do not have the entire story since I have not fully evaluated you, so please do not take this as complete clinical advice.
-Sonia
Wonderful article doctor .. As a practicing Endodontist I found this insightful !🙂
Dr. Seal,
The CBCT is such a powerful tool. Thanks for reading, it’s certainly can be a hard tech to master!
-Sonia
Hello, I have a failed root canal and wonder if my root is fractured. Would you read a cbct I had taken and give me a second opinion please? Thanks
Loire,
Unfortunately, the manner in which a cone beam was acquired makes a big difference in the resolution and therefore the diagnosis. It is possible that I may not be able to use your scan. There is a fee associated with this, but if you are interested, you can reach out to support@soniachopradds.com and see if this works for you.
-Sonia
THANKS for such a helpful article! And it’s kind of you to reply to patients too! Today I discussed CBCT with my dentist and said that I wasn’t sure it would help detect the extent of my molar crack. He seemed to think it might, but also that it would be able to diagnose if I have irreversible pulpitis, and if I need a crown or root canal, by noting the widening of the periodontal ligament. Do you find the CBCT is accurate at diagnosing pulpitis accurately? And can a radiologist consultant be very definitive about this? I’m just cautious of any more unnecessary sieverts. I even called my brother, who’s a radiation physicist, and now he’s wondering about the usefulness in this kind of dental case too. Thanks again… for helping SO many!
Dede,
If there is one limitation to the CBCT it is in identifying cracks in some cases. So, you have to look for other patterns. As for pulpitis, this will not show on the imaging, rather as the pulp starts to die you will start to see changes in the bone that can help with a diagnosis. So, the takeaway here is sometimes it can be too early to take a CBCT as there may not be any findings. However, if you wait, then findings may start to appear over time. It’s just important to understand a technology’s limitations. Nothing is perfect and it can be very hard to see some cracks on the CBCT. I could probably talk about this for days so its hard to get this info out in a simple comment, but I hope this helps.
-Sonia