How to manage broken instruments with confidence

Charlie Nicholas explores the reasons why a file may fracture and what to do in the event of these instruments breaking.

A recent systematic review indicated that the overall incidence of endodontic file fracture was 2.27% (Gomes MS et al, 2021).

In real-world terms, this probably means there is a good chance general dentists performing endodontic treatment may indeed encounter this issue at some point in their careers.

The potential difficulty lies in the physics and chemistry of the files we use, which, of course, are made of metal.

We have all seen for ourselves that if we bend a paperclip back and forth, the material starts to displace. This is known as work hardening.

As this movement continues, the crystal line changes. The metal actually becomes a bit more like a ceramic and subject to stress fracture.

With endodontic files, there are two causes of fracture (or a combination of both):

As with everything in life, prevention is better than cure. It is key that we clinicians do everything we can to mitigate the risk of file fracture.

The good news is that metal technology advancements have made inroads here in the form of heat-treated files.

The process that many endodontic file manufacturers use, including Endoperfection, involves heat treatment. The heat treatment changes the crystalline structure of the metal.

In a nutshell, the metal always ‘thinks’ it is warm, making the nickel titanium ‘happier’ to be bent.

There is plenty of evidence supporting the efficacy of this development, including Endoperfection’s own research.

We tested heated and non-heated versions of our Varyflex files at 250rpm around a 40-degree curvature.

The non-heated file fractured at 43 seconds, while the heat-treated version took 13 minutes and 26 seconds. The results speak for themselves.

As for minimising the risks during treatment, there are a few simple tips to bear in mind:

Despite best efforts, things can go wrong. The first thing to do is not to panic!

It is important to note at this point that breaking a file is not in itself negligent. It can be, but it still happens even if you do everything right.

So, as a small aside, in terms of record keeping, which is really an issue beyond the scope of this article, I would suggest that everything that is said in your conversation with the patient and the choices you make, alongside any action taken, must be recorded in their notes in full, accurately, and contemporaneously.

Be open with the patient about what is happening. In my experience, the term ‘separated file’ is better received that ‘broken’ or ‘fractured’.

Simply tell them what has occurred, that it is known to happen from time to time, it can be challenging, but you know how to help to get this sorted.

Now, you may feel up to the job or you may choose to refer. Either is fine, as long as you know your own limits and work within them judiciously.

There are a few pieces of equipment that can be helpful in these circumstances, such as Steiglitz tweezers, which can be useful if the broken file is simply sticking out of the canal.

You might also want to have to hand: wedging/micro tubes, cyanoacrylate (aka superglue) and methyl methacrylate, to snap-set the glue in the tube.

This will hopefully enable you to pull the whole thing out, including the fractured file.

On a more technological level, the IRS instrument removal ultrasonics system is designed to assist in the removal of intra-canal obstructions by dislodging them and, hopefully, making them relatively easy to retrieve.

What I would say is that, for the most part, file removal is challenging and unless the broken file is in the top part of the canal and you have straight line access, chances are you need to refer.

Of course, file removal is not always possible.

A broken file left in the canal does not necessarily mean that treatment is doomed. However it does need careful monitoring.

For example, sometimes the broken part can be bypassed, and successful endodontic treatment completed.

It depends on the individual circumstances. I would suggest that if you, as a general dentist, think this is the best option, you do need to be transparent with your patient about what is happening and refer them to make sure this is the best outcome that can be achieved.

No matter what happens, always remember that effective communication will see you through any circumstance.

Be honest, be open and be clear, and you and your patients can get through anything together, including separated files.

I would also suggest that a confidence-building course dedicated to broken file removal will help to stand you in good stead in such circumstances

It is something that is being developed by Endoperfection right now, so keep your eyes peeled for dates and locations.

Gomes MS et al. (2021) Clinical fracture incidence of rotary and reciprocating NiTi files: A systematic review and meta-regression; Australian Endodontic Journal; 47(2): 372-385

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