How does an instrument get into a root canal?

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We interviewed Denis V. Podilchuk, Endodontist and co-founder of the Ukrainian Endodontic Association.

Denis, at your clinic’s Website I have found amazing feedback from a patient. He thanked you for taking two instruments out of his root canal! I searched the Internet and realized that your patient is by far not the only one, who had to deal with this problem. But how is it possible that an instrument got stuck in the root canal and what kind of instrument was it?

A root canal is like a tunnel. To clean it out a dentist uses instruments made of medical steel or nickel-titanium alloy. But, however durable, all the metals dental instruments are made of are subject to the so-called fatigue. And if a dentist does not use a new instrument, uses one incorrectly or if a root canal is very curved, the instrument might split into parts.

That is it can break inside a canal?

Yes. According to statistics, this occurs in 2–5 % of clinical cases. The fragment itself does not cause inflammation, but the microbes that are present in the root canal do, because the fragment interferes with proper cleaning of the canal. Unsuspecting people often live with such fragments in canals, and they have no signs of inflammation.

How can a person guess that they have something in a root canal?

As a rule, you can see it on an X-ray, which must be done after root canal treatment, according to the root canal treatment (endodontic treatment) protocol. I can also often see instrument fragments through the microscope during treatment. If you find such a fragment, you can take a photo of it, take it out, and show it to your patient.

So, if a person had a root canal treatment and wants to make sure that the dentist did not leave anything there, he should have a control X-ray done?


Example: Root canal treatment shot up, with fragments of the tool, and then remove them

Is the protocol that you mentioned used in your clinic only or in all the medical institutions?

It’s a protocol recommended by the Ministry of Health, but it’s outdated. That’s why we follow an up-to-date protocol that is a gold standard of endodontic treatment. Before and after X-rays are an obligatory condition of good quality root canal treatment.

What if a dentist does not have the X-ray equipment?

If a dentist does not have equipment to comply with the protocol recommended by the Ministry of Health, it means breach of treatment standards. So the possibility of errors is much higher in this case. I do not recommend having treatment, where it is impossible to have an X-ray and control the quality of dentist’s work.

What if a person had seen one dentist and then went to see another and discovered that the previous dentist had left an instrument fragment in the root canal. What does he do in this case?

A doctor, be it a narrow specialist (an endodontist) or a general dentist, should first analyze the clinical situation and, having evaluated its various aspects, inform the patient if it is necessary to take the fragment out. If there is inflammation, the doctor should offer to treat the root canal once again: open it, clean it out again, remove the fragment and fill the canal. In certain clinical cases (when nothing bothers the patient, there is no inflammation), it is not advisable to take out the fragment, because you can damage the tooth and make it worse.

And if you leave everything as it is, will the person not feel anything?


Still, instrument fragments in the root canal – is it a relatively safe situation or a time bomb?

A broken instrument is always a complication. Dentists, however, say: “The one, who does not break an instrument, does not work.” Such situations have occurred, occur and will occur again. At the same time, this does not mean that a dentist should not minimize such complications.

Should a doctor, who performs root canal treatment, give guarantee on his work? And if so, how can a patient find out about it?

First of all, a dentist should aim to minimize risks in his work. At our clinic, in addition to control X-rays and using microscope in root canal treatment, we take stock of used instruments. We prefer to replace an instrument, if there is the slightest doubt in its “fatigue” and, correspondingly, risk that it can break. Disposable use of root canal instruments is not practiced in Ukraine: considering how expensive the instruments are, it would make the treatment 50% more expensive. A year ago we made a survey at our clinic, and 83 % of patients said that they are not ready to pay for a disposable kit. There are, however, those, who want a new set of instruments to be used for their treatment. We undoubtedly try to accommodate their wishes.

Root canal treatment is a microsurgical procedure. As any surgical procedure, it has more of a prognosis than a guarantee. If you have your appendix removed, you do not get 100% guarantee that the surgery will be successful. There are certain risks when removing a nerve as well. The outcome depends on both the dentist, and the patient’s immune system, type of microbes living in the root canal, anatomy, and state of the tooth. A favourable prognosis usually varies from 80% to 95% depending on the situation.

What other situations do you have to deal with? What do the patients come with to you most often?

About 70% are easy cases, when it is necessary to treat the canal again, and the rest 30% are complicated cases. These patients usually get sent to us from other clinics. Missed root canals take the top spot in the rating. A dentist misses 20-30% of canals when not using magnification (microscope) during treatment.

And why does a dentist miss root canals?

Human anatomy is unique to each individual. One person might have one root canal in a tooth, another – three or four. And treatment without magnification (without a microscope or binocular magnifying loupes) is done, so to say, by the touch or almost blindly. Due to magnification, a dentist is able to see tooth anatomy better. Believe me, an entrance to a root canal can be so small that it is sometimes difficult to find even with a microscope.

How is this issue dealt with at your clinic?

At our clinic root canal treatment is always done with the help of a microscope, because it allows us to clear out a root canal better, minimize risks and, correspondingly, achieve better treatment results.

What other complications do you have to deal with apart from missed root canals and instrument fragments?

We often get patients, who have calcified root canals. As a result of inflammation, a dental nerve tries to bury itself in the root and so makes the canal narrower. Dentists treating it without magnification risk not moving along the root, but making a hole in the tooth wall and going out into the bone, which, in its turn, is going to lead to new inflammation. As a result, the root canal will not be found and treated, and the tooth will cause continuous pain. We deal with such issues successfully at our clinic.

While we are talking about extraordinary cases, what else have you found in a tooth?

In my practice I have found cotton wool multiple times. It could have been in the root canal for five years or more causing inflammation. And it was both directly under a filling, and at the very end of a root canal, in the bone. How it got there, we can only guess.

Totally foreign bodies can be found as well. We had cases, where we found non-standard dental pins, which are not used in dentistry at all, instead of standard ones – like regular construction wire or a burr used to prepare a tooth for filling instead of a pin.

You mean a burr used to drill a tooth?

Yes, they took a piece of a metal burr and inserted it into a tooth. Besides, we often get sent patients, when a pin cannot be taken out. The matter is that, after root canal treatment, some of the teeth require restoration with pins. And, if the treatment was not done well or there were complications, you have to take them out. Some types of pins cannot be taken out without magnification, but, thanks to the microscope, we tackle such tasks with ease.

To tell you the truth, I’m greatly impressed by what I’ve heard. Could you give me advice on how to choose a dentist for root canal treatment?

The first criterion for choosing any doctor is trust, and a dentist is no exception. If there is no trust, it means it’s not your doctor.

When choosing a clinic, ask your friends and colleagues for opinions, but do not stop at that, because a dentist might not have a high professional level, but still be well liked and so recommended. Or, vice versa, a dentist might be a professional of the highest order, but not very good at communication. That’s why recommendations are only half the information you need to make a thought-out decision.

You should also make sure that the clinic you are going to really is at a good level and uses verified modern technologies. I recommend finding half an hour to read information on the Internet (e.g., at the clinic Website) and ask what is used for root canal filling and how it is done directly at the clinic. To paraphrase an old Latin saying “Forewarned is forearmed”, you can say “Informed is prepared”. Stay healthy!

Prepared by Maria Yarevtseva

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