Lateral canals — they are so easy to forget about as a potential culprit for root canal failure. When teeth don’t act right, we need to think outside of the box. It’s easy to blame a crack or even a missed canal, but what about a lateral canal? I forget about this little guy all the time, and it often stumps me in my diagnosis.
Let me walk you through this case so that I can show you exactly what I am talking about. Here are the preoperative radiographs…
Investigating the Case
When I first examined the radiographs, I felt as if tooth #3 should have been the problem. I really liked the way #2 looked on the radiograph, but I was too quick to judge because this patient had pain to percussion on tooth #2. That said, I diagnosed her with Previously Treated Tooth and Symptomatic Apical Periodontitis #2. I think we all know by now that in a case like this, I will take a CBCT. So, here we go…
Even after the CBCT, I still felt like the culprit tooth should have been tooth #3. This axial slice shows me that all the canals appear to have been found and obturated in tooth #2, but there was a potential for a missed MB2 in tooth #3. I was really surprised when I saw that it was #2 that was bothering her, and she was very localized to the percussion test on tooth #2. So I looked deeper into the CBCT, and here’s what I found…
I found this furcation breakdown and I didn’t know what it meant. Was it a sign of a crack? Was the root canal just recontaminated? Or was there a separate periodontal issue superimposed onto this root canal? I was stumped! Luckily, the patient was highly motivated to save her tooth. She BEGGED me to re-treat the tooth, and since we just don’t know sometimes until we try, that’s what we did.
Sneaky Lateral Canals
My root canal doesn’t look much different from the pre-op except for one minor difference — one of the lateral canals is radiating from the MB root that leads right into that furcal breakdown.
Now, I need to give a little disclaimer here. I re-treated this tooth with the GentleWave, and I don’t think that I would have been able to pick up that anatomy any other way. I wish I could fast forward a few months to see this thing heal. If it does, that will blow my mind — and it should blow yours, too, because it’s crazy that something so small could have such an effect! I promise to post the recall in another future post.
The moral of the story? We can’t forget that even one of these tiny little lateral canals going into the furcation can also make a tooth appear “cracked”.
Another Example
Let me show you another case. This patient had no pain, but clearly had a problem.
You can see that the tooth has been previously treated, but there is some furcation breakdown. Once again, the root canal looks fabulous!!
You can see from the bitewing that the tooth was not in occlusion, so the idea of a crack was just not in my differential diagnosis. Now I had to think outside the box. What else could be wrong? When I took the CBCT, all I could see was this….
Do you see it? It’s a periapical lesion that went into the furcation. This can be a very typical endodontic lesion, but I know that this would scare most dentists. This appearance of a PARL is normal to me, but I always want to know “why?” (and I absolutely hate it when it is not obvious). I let the patient know that I could try to retreat it, but that I couldn’t promise anything. Luckily, I once again had a motivated patient who wanted to try to save his tooth no matter what, so we re-treated the case.
Again, this root canal does not look any different than the pre-op besides that little lateral canal. But could this canal be the cause for failure? Probably!
My point with this blog is that we need to think outside the box with our diagnosis and consider that these tiny little lateral canals could be the cause of a failing tooth. So don’t be so quick to extract! Instead, re-treat to try to see if you can save a natural tooth.
Again, I can’t wait to fast forward a few months to see how this puppy heals.
A Handy Tool for Accessing Lateral Canals (and more)
Due to what I learned in the previous case, I also re-treated this case with the GentleWave. Not all dentists have embraced this technology, and it took me time to get used to it, for sure. However, the difference it has made is not the “slap in your face” evidence, but rather these little things that I am finding as I obturate. (You can read more on my GentleWave recommendations here.) But I do know one thing — it’s irrigating better than my syringe, that’s for sure! I don’t think that I could have made access into this lateral canal with the conventional root canal methods. Time will tell! (And I’ll make sure to show you the recall.)
Remember: Not all “bad” teeth are cracked!
-Sonia
Nice& informative mam.pls tell me your irrigation protocol..
In this case, I used the Gentlewave system by Sonendo. So, the irrigation is all built into the system.
-Sonia
beautiful retreats!
Maybe you’ve said before, but what filler paste are you using?
Hi Mike, I use Ribbon Sealer by Dentsply.
-Sonia
Thank you!! Very well illustrated. What obturación system do you use on these cases? Once you remove the debris is it your sealer and your obturación material that will flow into that lateral canal?
Hi Christie – I use a warm vertical obturation system. I am sure that it is a mixture of both materials that is flowing into that canal, but probably more sealer than gutta percha.
-Sonia
Hello Ma’am
Have you ever given an open dressing to any of your patients..
I’ve read about quite a number of dentists giving open dressing in cases such as an acute abscess with swelling
Hi there! I don’t ever leave a tooth open. My reasoning is that I don’t want to introduce any more bacteria into the tooth. The way I was taught is that this is an old school way of thinking so my recommendation is to keep all of your teeth closed at appointments. Hope this helps.
-Sonia
Hi
Nice work! I agree with your diagnosis. Scans are a very valuable tool . I do my endo with profiles. The key, as you have mentioned, is a lot of irrigation. That said I’m old school and still fill canals with lateral condensation and still get those lateral canals filled.
Hi Larry – Thank you for the comment. There is nothing wrong with old school!
-Sonia
In second case, if the tooth had considerable mobility, will you still recommend a retreat vs extraction ?
Sometime that’s a tough call when pt wants to save the tooth .
Definitely, interested in long term prognosis of these teeth with such furcation breakdown.
Hi Swati – mobility would still not scare me. Once I understand that the etiology is of endodontic origin, I know I can get all that bone back. Endo bone regenerates and the bone loss can make you think it’s worse than it really is. Disinfect the tooth with a root canal and you are back in business. The bone comes back and the tooth stops moving as well.
-Sonia
Hey.. Thank you soo much for such an informative post. I recalled so many cases that I had to refer for extraction due to this furcation perforation. After reading this blog I’ll be sure to look more deeply into my cases before reaching my definitive diagnosis. Thanks again! You r a gem!
Hi Hina – I’m so glad it was helpful!
-Sonia
Sonia, have you ever retreated just one canal, let’s say #19 had a short fill with a well circumscribed radiolucency . The mesial canals look perfect. Would you consider just retreating the D canal?
Hi Greg – yes I have. But it’s usually because there was a post in a canal that if I removed it, it would have a negative impact on the tooth. Most other cases, I will retreat the whole thing. I feel like it is all connected.
-Sonia