Where Memory Meets Flexibility
October 21, 2025
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PRODUCT REVIEW | Q&A | FROM THE PODIUM EARLY ADOPTERS WHY I USE
A new single-patient use line of diamond burs offers superior speed and efficient cutting.
KERR DENTAL
Where Memory
Meets Flexibility
With excellent flexibility for up to 90º curves, ZenFlex CM files combine high cutting efficiency with superior resistance to cyclic fatigue and file separation.
Like many of his peers, Dr. Rico Short was trained on using hand files for root canals and never thought the wiser—that is, until rotary
files came onto the scene.
“I remember when rotary files first came to market and people were like, ‘Are you crazy? That’s never going to work,’” recalled Dr. Short, a board-certified endodontist in Smyrna, GA. “Those first-generation rotary files were really stiff. They definitely took the stress out of our fingers, but if there was a round curved canal, a lot of them would break and sepa- rate. You were on pins and needles every time you used one, wondering whether it was going to come out in one piece.”
But over time, as nickel-titanium (NiTi) technology advanced and heat treatment was introduced, rotary files became increasingly more flexible, safe, and strong. “We no longer need to take a deep breath every time we’re using one,” said Dr. Short.
Controlled Memory in the Driver’s Seat
Today, Dr. Short equates rotary files to driving a car with power steering, and for many years, his vehicle of choice has been Kerr’s ZenFlex NiTi rotary shaping
file system. He recently added the new ZenFlex CM files to his routine, which leverage a proprietary metallurgy and heat treatment design that make them remarkably resistant to both cyclic fatigue and file separation.
“The new ZenFlex CM file is even better than the original,” he shared. “I love having the ability to pre- curve it, which is great for accessing tight areas, and the cutting efficiency and flexibility of the files are excellent. I don’t have to worry about them breaking easily, and I think that’s what makes them stand out from other systems.”
The ZenFlex CM file system is offered in comprehensive tip sizes from 0.13 to 0.30 mm and .04 and
.06 taper configurations—an upgrade that Dr. Short finds particularly useful.
“The new tip sizes are very unique and offer more incremental steps between sizes,” he said. “Most file systems stop at 0.15 mm, but this one has 0.17-, 0.15-, and 0.13-mm sizes, which makes it a much smoother transition—especially when you’re dealing with very small canal systems and a really tight apex.”
A Smoother Workflow
Since opening Apex Endodontics 20 years ago, Dr. Short has treated countless patients in his practice, including some notable celebrities.
“It’s a pretty fast-paced office, so we need to have file systems and equipment in place that match the efficiency and quality we provide to our patients,”
he said, adding that he’s seen many patients’ dental IQs skyrocket in recent years. “We want to make sure we’re using the latest technology because our patients demand that.”
By and large, the curve of ZenFlex CM files affords Dr. Short a much smoother workflow vs other less flexible file systems. “We can take care of patients efficiently without losing quality,” he concluded.

RICO D. SHORT, DMD, BCE, FICD
The opinions expressed in this article are those of Dr. Short, who is a paid consultant of Kerr. Clinicians should use their own professional judgment in treating their patients. Kerr is a medical device manufacturer and does not dispense medical advice. The article was originally published by Dental Product Shopper.
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