What’s the best way to give root canals a bad reputation? A missed root during root canal.
As an endodontist and educator, one of my primary responsibilities is to continue to dispel the harmful myths that have emerged and persisted around root canals. For decades, the dental community has had to contend with literature and even full-length documentaries that drive fear around root canals and what they do to our bodies. Most of these false claims are grounded in the idea that root canals never truly heal—they will always be home to harmful bacteria that will only cause further pain and infection.
If that were true, I would understand why so many patients assume they’ll need to have their teeth extracted! Fortunately, though, all those fears about root canals are totally unfounded. As every trained endodontist knows, a properly performed root canal is perfectly safe, and has the added benefit of balancing out a patient’s microbiome while saving their natural teeth.
However, as with any medical procedure, it is true that a failed root canal can cause complications later on. That’s why it’s imperative for any dentist to stick to the two cardinal rules of root canals:
- Find every single canal
- Get to the end of every single canal
When you follow these two rules to the letter, your patient’s root canal will heal just fine and they’ll become a believer in the power of endo. When you don’t … that’s when the problems start. And that’s exactly what happened in this tooth story.
The Story of a Missed Root During a Root Canal
The patient in this tooth story was a 28-year-old woman. About a year and a half prior to seeing me, her general dentist performed a root canal on her upper premolar. Although the root canal had seemed like a success, the patient was now experiencing a painful bump around the previously treated tooth.
When I looked at the patient’s periapical X-ray (Image 1), everything appeared to be in order. But upon clinical evaluation, I found the tooth to have pain to percussion and biting. I knew it was time to take a second look with my cone beam.
When I reviewed the CBCT scans (Images 2 and 3), I quickly found the source of the patient’s discomfort—there was a missed root during the root canal. Somehow over the course of the original procedure, this patient’s dentist had failed to identify—or to treat—a DB root.
I want to be clear: this tooth story isn’t about shaming this patient’s general dentist. Instead, it’s yet another example of how much it pays off to invest in endodontic technology. That missed root during the root canal was almost impossible to see using traditional X-rays, but it was clear and defined in the 3-dimensional cone beam scan. Having a cone beam on hand could have prevented this failed root canal and prolonged suffering on the part of the patient.
With the help of my CBCT, I was able to diagnose the patient’s previously treated tooth with symptomatic apical periodontitis.
Retreating the missed root
With a diagnosis in hand, I got started on retreating the patient’s tooth. If you take a look at the coronal view of the cone beam scan (Image 4), you’ll see I really had my work cut out for me! That image shows the substantial bone resorption around the root that resulted from the tooth infection. It also shows how the tooth infection thickened the maxillary sinus membrane. (Both of those symptoms normally resolve themselves after retreatment.)
I opened the patient’s tooth back up and removed the restorative filling material. Then I got to work with my file. Image 5 shows that working file in the untreated DB root, identifying its correct length and location. As with any endodontic retreatment, I made sure to clean and fill all of the canals, even the previously treated ones. The last thing I wanted was for this tooth to get another infection! You can see all the cleaned and refilled canals in the conefit X-ray (Image 6).
Lastly, here’s an image of the final filling and obturation of the retreated root canal.
How to avoid missed roots during a root canal
I am thrilled to report that this patient’s second root canal was entirely successful—her bone regenerated, and that annoying bump went away! But even though this tooth story had a happy ending, it still makes me a little sad. That poor patient never should have had to step into my office, and I hate to think that her initial experience of the failed root canal may have contributed to some of the harmful myths around their efficacy.
So, in the spirit of endodontic education, let’s do a recap of the key takeaways from this tooth story.
- Always follow the two cardinal rules of root canals: Find every canal, and get to the end of every canal! If you don’t do that, the patient’s risk of contracting some new infection drastically increases.
- Invest in endodontic technology. This patient’s general dentist wasn’t bad at his job—it was impossible for anyone (including me!) to see that third canal without a cone beam. Traditional X-rays are great, but relying on them can lead to a missed root during a root canal.
- Refer your patients to specialists when applicable. This relates back to the previous takeaway—general dentistry offices may simply not have access to the advanced tools available at a specialist’s office. Additionally, endodontists have years of experience identifying and treating tricky-to-find canals.
All that being said, a missed root during a root canal can happen to the best of us. When it does, it’s even more imperative to retreat the tooth quickly and effectively!
What experiences have you had with missed roots in your practice? I’d love to hear about it in the comments!
– Sonia
Which material is used for closing the crown opening…
Abdul, I use composite.
-Sonia
Thank you so much ma for sharing. The use of contemporary imaging is key too, as it could help in locating occult canals.
Thanks so much for reading Dr!
-Sonia
very helpfull ma’am and thanks for sharing.
Thanks for reading!
-Sonia
i have a missed canal, funny i had the impression that i had but when i pointed to the spot the dentist saud it was just tooth decay there. but i also got tbe bump now and the choice between root tip resection and pulling. as a revision toot canal isnt covered by dental insurance.
Hi there. If the option is there to redo the root canal, I am a firm believer that is always the best option. Of course, I do not have all the data to give you an accurate diagnosis, so I would trust your provider. Unfortunately, dental insurance does not cover much and I always urge patients not to rely on your dental benefits since they do not work like medical benefits.
-Sonia
It should be the dentist’s responsibility to refund the cost of the failed RCT and insurance cost so the patient is able to use their insurance benefits to have a chance to save the tooth, e.g. , retreat and re-crown the tooth. As mentioned, insurance won’t pay for same procedure on the same tooth for up to 5 years. This is really unfair to patients, especially when they are not advised that they have the option of having root canals done by an Endodontist. It is not fair to have to lose a tooth, bone loss, thousands of dollars and insurance benefits due to dentist’s error…not to mention the pain and suffering because the dentist missed cleaning a canal and “sealed in” the infection, allowing it to spread. It is really the patient who loses out in so many ways when this happens. By the time a complaint can even be reviewed, it is too late for the tooth.
Hannah,
You have a really good point. This is why I encourage all patients to be advocates of their oral health and to understand their options. Everyone has the option to have their treatment done by a specialist, but first we need to create the awareness that specialists exist. On the flip side, there are many patients who refuse to see the specialist. The risks and benefits need to be understood by everyone. You as the patient have a right to make your own choice.
-Sonia
Hello Dr Sonia, I have a question is long term prognosis of a successfully done RCT. I have told from multiple endodontists say, every rootcanal will eventually fail at some point. How are your though on this? what is your time line of how long a RCT last or if that even true or is it just a myth.
Levi,
I don’t know any endodontists that would say that. My goal is for that patient to take that tooth to their grave with them when they go :).
-Sonia
Hi Dr Chopra! It’s been a while since we last chatted , This was possibly on one of your lectures. Anyway how are you? I’ve been following your postings and try to read them all!
I’ve learnt so much from you.
I’ve had a few retreats sent to me for other general dentists . The last one being a left mandible second molar. The patient presented with the usual symptoms: pain, buccal sinus .
I removed all the GP points from the previously treated RCT and located an untreated MB CANAL. The hardest part was removing the old GP points . I used a hybrid rotary file and has some eucalyptus oil over each orifice . This did the job and I’m happy to report the patient is now symptom free.
How do you remove your old GP points for your retreatments?
Do you obturate in that sitting or do you medicate the canals for 6 weeks ?
Let me know .
Micheal,
I take my GP out with a rotary on high RPMs after I have dissolved it a bit. And if I am retreating my own case, then I definitely do it over at least one month.
-Sonia
Could you please do a blog explaining proper protocol for retreatment.
Tim,
I sure will get that in queue, but I believe I have written one in the past. I would check the blog page on the website a bit more closely and even check out my videos on youtube.
-Sonia
Dear Dr. Chopra,
An excellent article.
Having a CBCT for endodontics is getting closer to the accepted standard of care, certainly in the specialist’s offices.
For those of us in small clinics or solo practitioners, the costs of a CBCT are challenges for competing technologies.
I would suggest the surgical operating microscope should be the priority.
Do you have any suggestions on how offices without CBCTs can obtain those services in a time-sensitive manner?
Thank you,
Douglas
Douglas,
Perhaps you can work with your specialists or a scan center. I don’t really know the answer to this, however, there is always a return on your investment. It’s all in how you look at these things. Thank you for your comment.
Patient came to me for root canal tooth #5. Took cone beam and identified two canals. Cleaned and filled both, placed post and crown. Patient returned in six months with symptoms. Took another cone beam and the buccal canal split into two about 1/3 of the way down. I failed on my initial exam and review of the cone beam to view the entire tooth closely all the way to the apex. Ugh! Patient lost faith in me and went elsewhere. I now look at all angles, all the way to the apex in all views!!
The CBCT will save us every time! Thanks for sharing.
-Sonia