File Lineup Boasts Better Flexibility and Durability

Richard Gawel


Root canals require files that are flexible as well as durable. Coltene developed its HyFlex EDM lineup to satisfy these dual demands. An electric discharge machining (EDM) process yields up to 700% more fracture resistance over previous files while reducing the risks of ledging, transportation, or perforation, according to the company.

“I don’t have the ‘What if?’ in my mind when I go into a case,” said Jeffrey R. Briney, DDS, who has been using the files for the past few months. “I feel like I can put a lot more pressure on it and let it work harder, whereas some of the other files, I’m too worried if I feel engagement, it’s going to snap in there.”

The EDM process generates a potential between the workpiece and the tool. The sparks generated in the process cause the surface of the material to melt and evaporate, creating the NiTi files’ unique surface and making them both stronger and more resistant to fractures. Dentists, then, don’t need as many files during root canal treatment.

“I’ve done everything from initial endodontic therapy to retreats with the EDM files,” said Briney. “I went from using about 6 different files to 2. It also eliminates from the 25 file straight to the 40. So, those 2 files are eliminated between those 2 steps.”

These files are more than reusable, though. They also benefit from a controlled memory effect. During a procedure, files tend to lose their spiral shape. But by applying heat, typically in an autoclave, the files return to their original shape and regenerate their crystal structures, restoring their resistance to fatigue. That resistance is key to efficiency.

“Doctors obviously don’t want to leave part of the file in the canal. They’re trying to remove the pulp tissue. They want to get everything out of there,” said Amy Tuttle, global product manager, endodontics, at Coltene. “If a file breaks, they may take an hour or more to try and remove it, or, if it’s a GP, they may have to send that patient to an endodontist.”

There are 6 files in the HyFlex CDM lineup, beginning with the 25./12 orifice opener and including the 25/~ variable taper and 40/.04, 50/.03, and 60/.02 finishing models. Each of these files can be used at 400 rpm with a torque up to 2.5 Ncm. The 10/.05 glidepath file can be used at 300 rpm and 1.8-Ncm torque.

In addition to the EDM process, the shape of the files provides durability and flexibility. Each file starts off with a rectangular shape and then progresses to a triangular shape, which Tuttle says is unique.

“We’re able to make a quadratic tip, which is strong and less likely to separate in the canal,” said Tuttle. “Further up we go to a triangular shape, which makes it more flexible so it is able to work its way through the canal without causing transportation or ledging.”

The HyFlex EDM Introkit Compact starter set comprises 4 file sizes that practitioners can use to preform treatments, particularly straight canals, to ISO size 40. All HyFlex EDM files also are presterilized, so dentists can use them right out of the box without delay.

“I’ve found that patients feel less stress. They can see that things are going much smoother and flowing quite well, how easy it is. My assistant sees how easy it is, too. And I know they’re getting an outstanding technique,” said Briney. “In probably 20 years that I’ve been practicing, it’s been the easiest segment of my career in endo.”

For more information, visit Coltene’s website.

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