Patient Story: When X-Rays Aren’t Enough

By: Dr. Sonia Chopra

The saying goes “Don’t judge a book by its cover.” And in dentistry I say, “Don’t judge a tooth by its x-ray.”  Also, don’t assume the worst — give things a chancroot e.  That’s how I practice endodontics. I never say “never”, and I always give teeth a chance. I won’t know if a treatment is going to work until I try.  This philosophy that I live by served one of my patients well!

My patient was a 35 year old woman with pain in a tooth that had already had a root canal. She came to me as an emergency case, experiencing lots of pressure and pain. Usually, I try not to “meet and treat” my patients because I need time with them – they have questions that I want to answer. I like to make sure the patient understands their treatment and treatment options, and I want to make sure I am treating the right tooth.

Getting the patient to understand the “why” of their treatment is key, and that takes communication, transparency, and patience.

However, if the patient’s pain is characterized by intense pressure and they are in tears, I reassess the situation and treat immediately. I know that their tooth is trying to drain of the infection inside, and I want to make that happen for them.

When a patient comes to me and their tooth already had a root canal, my protocol is to take not just x-rays but a 3-D cone beam image as well.

Here are my patient’s root canal tooth xray:

root canal tooth xray

root canal tooth xray

And here are my patient’s 3-D cone beam images, that can show cross-sections inside the teeth:

root canal tooth xray

root canal tooth xray

Some dental professionals would have said that the cone beam images suggested this patient had a vertical root fracture in her tooth… and that was possible, and most definitely a part of my diagnosis. But I could not be certain.

The x-ray imaging looked like the previous root canal had been done well. But since I had no history of the tooth and the patient didn’t remember any details, I had to keep in mind that it was possible that the tooth had a new bacterial infection that had nothing to do with a crack. It can be easy to blame pain and infections on cracks when treatment isn’t working, but bacteria is a more likely culprit.

There are so many variables I did not know about the initial treatment. Was a rubber dam used during her previous root canal to keep the tooth free of bacteria ? Was the tooth cleaned properly during the procedure? How long did it take the patient to get her crown after the root canal?

I gave the patient her treatment options: we could retreat the tooth with another root canal, or extract the tooth and she would need an implant. I explained to her that, even if she chose a second root canal, I could find a fracture in the tooth and it would still need to be extracted. She wanted me to try it anyway. Complete transparency before starting procedures is extremely important to me, and to my patients.

What I found surprised me!  When I accessed her tooth to start the root canal, the previous root canal filling (called gutta percha) was black, black and black! The gutta percha was so contaminated by infection that it turned black. I was so surprised to see the level of infection in the tooth.

root canal tooth xray

Once I removed the gutta percha, the infection started to drain.  And THIS is the key to helping a patient feel better. Instant gratification for both me and my patient!

Proper diagnoses from a dental professional can require putting together lots of clues. I understand that there’s a learning curve to reading cone beam images, and they can be misinterpreted. Some would have thought to take this tooth out because of a possible fracture (since root fracture can cause pain after a root canal). If your dentist is not 100% definitive in the cause of root canal failure, then they should access the tooth for a visual assessment to be sure. Sometimes we don’t know the answer before going into the tooth. And your dentist should prepare you, as the patient, for the potential outcomes of the different types of treatment.

The cone beam for this patient did not look good, but if I had judged the tooth by its root canal tooth xray, I would have done a total disservice to this patient. It would’ve been a complete misdiagnosis, because the root canal infection didn’t show up on the X-ray.

I was lucky that the patient wanted to try and save the tooth. It was the right choice for her and her health.

root canal tooth xray

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