Most times when a rotary file breaks in a canal, the fragment is either irretrievable or the risk to remove it is greater than the benefits. This is purely because they mostly break apically, around curves, and the fragment is often no more than 3-4mm in length.

Using ultrasonics to remove a fragment in a situation like that can very easily lead to excessive damage to the apical aspect of the root. Apical surgery is often a more predictable approach if the fragment must be removed. Many times, however, the prognosis of completion of endodontic therapy with the file fragment still lodged in the root (ie. obturation that incorporates the fragment) can lead to a decent prognosis still. It all depends on the presence or absence of preoperative infection within the tooth and the management of the tooth through the whole process.

I have found that when instruments break in canals like this, it often is more a manufacturer’s defect than poor technique.

Here you’ve got a fairly thick file that broke off leaving a long segment in the canal. The canal is fairly straight and the head of the fragment is visible in the coronal aspect of the canal. I was able to trough around the fragment to about 2mm beyond the head of it. The energy from the ultrasonic tip them unscrewed the fragment and it popped loose. Often applying the ultrasonic directly to a fragment will cause the fragment to further fragment, but this piece was thick enough, not around a sharp curve, and visually accessible enough that I was able to retrieve the file and proceed to complete the endo normally.

On the post-op film you can see how close I was to a perforation of the root even though I had good visibility of the fragment through my microscope. Imagine trying to do all of that troughing in the apical third of the root.

Note that this file has radial lands, a larger tip diameter, and a greater than 0.04 taper. It’s probably a GT file.

The first picture is how this premolar arrived (with the patient) to my office. Discharge was present through the gums from a chronic abscess. Looks like a radiolucent post was placed practically to the apex. There’s some remnant gutta-percha or cement mid-root and probably an apical perforation at the base of the post.

The tooth was retreated over a couple of appointments. Sure enough there was a perforation at the apex of the root, but laterally. I was never able to regain the true canal beyond the perf. A carbon fiber post was removed, Calcium Hydroxide was used as an interappointment intracanal dressing, and then MTA (Mineral Trioxide Aggregate) was used to fully obturate the canal.

There is a 21 month interval between the two films. Osseous healing is progressing well, and no mucosal lesions were evident at the time of the second film.

This case also serves as an example of the fact that a 1-year recall on endodontic cases does not provide enough time to properly evaluate healing. From a strict radiographic interpretation, this case has not healed and is therefore not currently a success. One strike against the relevance or clinical significance of that Cochrane Review.

By the way, I did address the molar’s obvious periodontal issue verbally. The patient is aware of a guarded long-term prognosis there.

It’s not usually a good thing when your dentist says “oops” during a procedure. I’m sure that the dentist who did this didn’t say “oops” out loud, but instead thought something much more profane when he saw what he had done.

The patient has been experiencing episodic symptoms for almost a year (since the implant was done). The periodontist who did the implants bounced the patient to an endodontist and an oral surgeon. Nobody really wanted to do anything. A CT scan was ordered by the oral surgeon and, although results were not conclusive, there were findings consistent with the fact that the implant was in contact with the root of the tooth. It was difficult to determine if the canal space had been perforated.

The patient was eventually referred to me for a second endodontic opinion. I recommended exploratory access and a retreatment start. The film above shows the story after I had accessed the crown, cleared gutta-percha from the canal, and then loaded the canal up with Calcium Hydroxide paste. The plan was to leave the tooth in this state for at least 4 weeks to see if symptoms improved.

During instrumentation of the canal, I found a solid, wide blockage in the apical 1/3 of the canal but fairly short of where the root should have ended. Electronic apex locator readings showed an apex at this blockage. These finding are consistent with the blockage being a metallic object that had perforated the root.

Over the past few weeks our patient has not noticed any significant relief from the current treatment. This means that completion of the retreatment will make no difference either. I’m not interested in doing apical surgery around an implant, so back he goes to his periodontist for further direction.

I was watching this video, thinking that the dentist was doing an ok job. The only things that made me a little worried were the lack of eye protection on the patient and the extremely long hair the assistant was tossing around.I was about to give a passing grade until he said that he’s putting a titanium post into the tooth to strengthen it. That’s completely false. He should know better and if he does, he’s doing an unnecessary value-added service (that will increase the fracture potential of the tooth)…from what I can see of the tooth the post is unnecessary from even a restorative-retentive perspective.

So why does it matter to me what the restorative dentist does in the tooth? The answer is ethics for one, and the second reason is more selfish. Often the first thing to fail in a tooth that is having trouble is the endo. In today’s society where people take no responsibility for their actions and find it much easier to assign blame to others, the patient shows back at my office with the impression that their tooth is having trouble because of inadequacies with my work:

March 2006, consultation appointment. A long discussion about why this 1.5 year old endo is episodically symptomatic. Her dentist did the work. I recommended retreatment, another discussion ensued about the post and the reason it was placed. She was not optimistic about root canals in general because of the history of this tooth.

December 2006. Because of the patient’s trepidation about endo, I decided to medicate the tooth and only complete the retreatment once signs of osseous healing were evident. I babysat the tooth while it was medicated for a few months and saw some obvious signs of healing. Symptoms had also disappeared. Retreatment was completed. A discussion about posts ensued again because the patient was wondering whether one was necessary or not. I told her I didn’t see a need for it because of the amount and strength of internal structure.

Last week. The patient’s dentist sent her back to see me because the tooth has been episodically symptomatic (demonstrating recurring parulis formation) since the retreatment was done. Upon further questioning, the patient said the tooth started acting up after the permanent restoration in the crown was done. She said she told her dentist she didn’t want any posts and he said he wouldn’t do the filling unless he put posts in. He insisted, so she felt she had no choice.

From the film it’s obvious that a non-metal post was placed in the P canal, gutta percha has been removed from the coronal 1/3’s of the buccal canals and material consistent with the core resin was placed into those areas. Apical bone appears good still, a lesion has developed in the furcation. The lesion in the furcation is associated with all of the work that was done in the coronal canal areas. There’s likely been a strip perforation in one or more of the roots. My guess is the MB root.

As much as I tried to diffuse a potential situation with this patient, I know that she’s going to have a few unpleasant words with her dentist.

I’ve been sifting through some old files and came across a presentation I gave a few years ago. This one slide from the lecture is interesting because it shows two areas where we often see canal transportation.

The arrows point out the mid-root area where strip perforations can happen (where inflexible instruments straighten the canal out there), and then the apical area where “zips” can happen.