File separation

What to do about an endodontic file separation?

Endodontic file separation during a root canal can and does occur. So what can we do about and what should we do about it?

What happens when you have an root canal file separation?

The first thing we will do is evaluate the situation. As you can read below there are times when it is inconsequential and we do not do anything different. An example of this would be when we are almost done cleaning out the canal of a vital tooth and we experience a file separation in a spot we know will be tricky to remove. At that point attempting to do anything is likely to just cause more harm than good.

Once we evaluate the situation we will determine whether or not an attempt at removal is prudent. Retrieval of broken segments deep in a root with a curve can be very risky to remove. Removal at the very least will result in more tooth structure removal and weaken the tooth. Worse can cause strips which is not taken care of will result in failure of the tooth. If we determine removal is necessary we will attempt to remove the file. There are file retrieval systems but we prefer a series of smaller and smaller piezo tips like the ones from Denstply. If we are not able to remove the file and the tooth does not heal or is still painful, then an apicoectomy is the next step.

Root canal file separation in palatal canal at apex

In a case like this, vital and file separation near end of appointment at the apex, very minimal or no attempt being made to remove is acceptable. What’s interesting about this case is the canal we were concerned about, the severe curve on the mesial buccal canal, looks great!

Why do files separate?

The newer file systems are less likely to separate than older file systems. This is mainly due to the way they process the metal. Furthermore the reciprocal systems are much less likely to experience a file breakage vs the rotary systems. However, experience of the operator is the biggest risk factor for who will experience a file separating during a root canal. A dentist with more experience will have more file separations in their career and will likely have learned from their mistakes.

The biggest issue we see is not developing a straight access line in a root with a curve, such as an MB2. The anatomy of the tooth is also a major reason why files will separate. However, a lot of that can fall under the experience category and knowing when there is risk. Over using files is another issue but again, you learn your systems limits with time.

Small file separation on a lower molar

In this case there was a small file in the distal canal. It was not the cause of failure though. The distal has two distal canals and only 1 canal was done, thus causing the failure. This case is on our selective retreat blog.

How big of a deal is an endodontic file separation?

It may not matter at all! Or it may be an almost guarantee to cause a failure of the root canal procedure. The main determinants are at what point during the procedure the file separation occurs and whether or not the tooth was vital or necrotic.

A necrotic tooth needs to be thorough cleaning and disinfection to be successful. A vital tooth has more of an ability to heal itself. So if a file separates at the tip of a vital tooth, this may not be an issue. As far as when it occurs, the later in the procedure the better. If the dentist is almost done with that canal, then it probably does not matter at all. The file is basically the filling material now. If it happens early on, which is more common, then the root canal was essentially not done past where the file is stuck.

Another factor on the severity of the file separation is where the file is. If it’s up higher in the canal we have a better chance to retrieve it which is good. However, if we can not retrieve the file, then higher is much worse because all of the portion below the file still has not had ant treatment. If the file separation is lower then the chances of retrieval are lower. This is almost always a worse situation. A file separation outside of the apex is impossible to retrieve.


Case study of a file separation

In this case there was a file separation in #13. The case was sent to Dr. Bauer to attempt retrieval and for the retreatment of the failing root canal on #12. We were able to use a piezo to visualize and removal the broken file. Both #12 and #13 have 2 canals. Viewing the CBCT, we can see that #13 has severe curvature in the apical portion. The curve is a contributing factor to the file separation in that area.

Endodontic file separation retrieved and root canal retreatment of another tooth.

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