Were you taught in dental school that J-shaped lesions meant that the tooth was fractured? When you see that J-shaped radiolucency on a radiograph, does your heart sink? 

Well, it turns out that it doesn’t always have to be a cause for despair! This misconception about J-shaped lesions and vertical root fractures is, honestly, flat-out wrong.

Honestly, if there were one thing I could unteach everyone about endodontics, it would be this misunderstanding. Honestly, the idea is really starting to make me upset, because it’s leading to a lot of unnecessary extractions. 

Before we go any further, I want to draw your attention to the word “fractured” in the first paragraph. I have noticed that the words “fracture” and “crack” get thrown around loosely and interchangeably sometimes, and that’s pretty clinically confusing. To me as an endodontist, they’re very different! Fractured, to me, means non-restorable, while cracked means there is a crack but it can be restored. That poor tooth doesn’t always have to go in the trash! So let’s be clear about our nomenclature with these two words.

Why Does this Matter so Much?

I’m all about saving teeth, as you know! If you have been following me for any amount of time, you know that my motto is Give Teeth a Chance. I have had so many patients come to me throughout my career that want me to save their tooth because they have been told that their tooth prognosis is hopeless. They want to see if there is even a small chance that their tooth may be saved instead of extracted. If the universe did not deliver me these patients, I don’t know if I would have ever started writing my blogs. 

Plus, my own tooth story—missing eight teeth when I entered this world and saved from a horrifying infection by a root canal—makes me believe that I was born to do this work. I am here on this planet to share my voice about saving teeth. I’m here to empower dentists to rethink and reframe the beliefs that we were given while we were in dental school.

Are you open to having your belief about J-shaped lesions reimagined today? Are you open to the possibility of understanding how to be successful and confident when you are faced with a J-shaped endodontic lesion?

In this blog, I showcase two teeth with J-shaped radiolucencies. They have two very different outcomes. As a side note, these teeth came into my office in the same week. Coincidence? I think not.  They came in so that I could teach you this new learning!

J-Shaped Radiolucency Case #1

This young lady had a very good looking previous root canal. When root canals look like they were done well, I question if perhaps bacteria is getting back into the tooth via a crack, which would mean that the tooth would need to be extracted, not retreated.

From the radiograph, you can see the J-shaped radiolucency around the distal root. 

I also traced a sinus tract on the buccal.

So this tooth was diagnosed as Previously Treated and Chronic Apical Abscess #30. And from the CBCT, you can really appreciate the J-shaped radiolucency here…

And here is the bone loss pattern in the coronal view…

And the axial view…

Now, let’s be honest. Would you send this tooth for an extraction at this point?

I think it’s important to understand our beliefs along the way. I, too, thought that this tooth had a questionable prognosis. Every time a J-shaped lesion shows up on imaging, I get a little worried; but in this case, I also had hope. 

Ultimately, the treatment decision was not mine to make, and I cannot impose my beliefs onto my patient.

So, I had a deep discussion with the patient about the possibility of finding a fracture internally within the distal root. If I could see that during the procedure, then the tooth would need to be extracted. I presented her all of her treatment options including 1) retreatment, 2) attempt retreatment but if I find a fracture then extraction, or 3) go straight to the extraction.

She opted for 1 & 2: do the exploratory retreatment, and if we find the fracture, then she is aware that extraction will be needed.

So, we started the retreatment and removed all of the gutta percha. I inspected all of the walls with the microscope and saw nothing… no fracture, NADA! So, I continued to disinfect the tooth (with the GentleWave) and then obturated the tooth.

You Have to Really Look Closely

What do you appreciate in the final radiograph? It’s subtle, so you have to really inspect it. 

Here’s a hint: Look at the surface area that the gutta percha has now filled into.

I know it’s hard to compare that to the preoperative radiograph since the distals are not that split apart, but there was so much surface area between the distal canals that still needed to be disinfected and treated. My hypothesis is that this area was still harboring some serious bacteria. Only time will tell if this tooth heals. I will make sure to get a recall radiograph in a year.

I can tell you one thing, though… the tooth stands a chance now. Even with a J-shaped lesion, endodontic treatment can sometimes make all the difference in the world and can give that tooth a chance. If you extract, it’s a one-way street.

We need to give this patient the time it takes to heal such a large amount of bone loss. She is also keeping an eye out on that sinus tract. If it doesn’t start to resolve within the month, then we still have a problem.

It is still quite possible that there was a fracture internally that I could not even see with my microscope.

And I think that this is the interesting part about this case. I still don’t know if this tooth is fractured or not. I need to wait and see how it heals, and then I can make a full proper assessment.

We dental professionals are typically very quick to make our judgment about a case, but I want to push back on this, and suggest we slow down. Let’s reimagine our beliefs in ways that can fully serve our patients. It’s not easy to admit to our patients, “I don’t know,” but sometimes it’s what we need to say because no one has a crystal ball. No matter what, it’s our sacred duty to heal our patients as well as we possibly can.

J-Shaped Radiolucency Case #2

Let’s move on to the second tooth story. This young man was told by his dentist that he had an infection in his tooth that had a previous root canal. He had had no pain whatsoever. You can see that J-shaped lesion very clearly on the preoperative radiograph (but remember you could see it on case #1 as well)…

The CBCT outlines that radiolucency very well too…

In this case, I did the same thing that I did in the prior tooth story: I had that detailed discussion with the patient about his treatment options. Patient empowerment and informed consent is extremely important to me.

I actually thought, in this case, that the etiology of root canal failure could have been the short obturation and the poor condensation, so I really thought this tooth had a chance (more than with the tooth story I shared first).

So with the patient’s permission, I removed all of the gutta percha and inspected the internal walls of the root canal system for a fracture. This time, I thought I saw something. Uh oh, better look closer!

One thing that I like to do is to run my GentleWave at this time. Why? Because if there is a crack, then the GentleWave will clean the walls to help me visualize that crack more clearly, and be more confident in my diagnosis. And sometimes, it will even clean it to the point that it lets in some heme from the periapical area.

And that’s exactly what happened.

The picture is fuzzy, so just in case you don’t see it, here it is outlined. You can see that it is traced by blood from the periapical area…

What Can We Learn from These Two J-Shaped Radiolucencies?

Let’s put the preoperative radiographs side-by-side. You can appreciate how very similar they look from the outset!

Even if a tooth has a J-shaped radiolucency, it doesn’t mean an automatic extraction. A J-shaped lesion doesn’t necessarily mean there is a vertical root fracture present. Empower your patients to understand what their options are, and that you can’t guarantee an outcome for them if you try to treat the tooth. But it really can be worth a shot much of the time.

I hope that this blog has started to shift your beliefs. What you learned about J-shaped radiolucencies in dental school was most likely oversimplified, and there’s more to the story than most dentists realize. But you can be different!

Remember, we became dentists to save teeth, not to take them out. We were born with teeth to use them, not go without them. As dentists, we are healers.

For more thought-provoking tooth stories and endodontic tips, I invite you to subscribe to my email list. You’ll receive weekly emails that can make you a more effective and efficient provider. Welcome to my endo community!

– Sonia