Stacking the Deck : A response to questions about our selection of testing protocols


Recently, we received feedback regarding our methodology for creating protocols for evaluating endo file performance on our Endo File Evaluator, a computer controlled clinical simulator. As always, we encourage your participation in our discussions and we felt others might benefit from including these comments in our public forum. The comment submitted through our website contact form is as follows:

“I’ve been looking over some of your data comparison in regards to your Evaluator V2 and am borderline appalled at how misleading it is and how you’ve set your file system up to succeed in that scenario and make sure that others do not perform. You have all 11 file systems in that Evaluator V2 running at 550rpm [sic] knowing good and well that for several of the file systems on there 550rpm is much higher than the recommended speeds Many of those systems run at 300rpm. Not to mention the torque you are using in the settings is also much higher than normal for many of the files. I find it to be quite a coincidence that the speed you choose to do the Evaluator V2 test comparisons at is the exact optimal speed of your own file. It seems to me that without testing each of these systems at their optimal speed torque technique your are doing nothing more than publishing skewed results that have been made to lean in your direction.”

Were this in fact the case, we also would be appalled. Distinguishing hype from fact was precisely the reason Dr. McSpadden developed his Endo File Evaluator. The protocol mentioned and its use of 500 rpm and unlimited torque setting is actually arbitrary and was intended to establish a baseline for future comparisons. Our goal with protocols is primarily to find the limitations that dictate optimum performance. The first series of protocols takes various file sizes to a canal’s apex with a particular speed and rate of insertion with no regard for the file’s size relative to the canal opening. This is not a technique we, or I dare say anyone else, would ever recommend using in their practice.

Rather, our methodology allows for direct comparison of torque and pressure readings that may be viewed in a graphic format and ensures a level playing field for interpreting the data. Previous testing performed on the V1 Evaluator used several various protocols with multiple rotation speeds and insertion rates. This data informed Dr. McSpadden as he wrote Mastering Endodontic Instrumentation and ultimately inspired his design of the One Endo file. It has always been our intent to continue our testing and comparative analyses of endo files using an ever broadening scope of protocols. To that point, we  are currently completing a full evaluation of most endodontic file designs in an ongoing series that we will share as a new blog scheduled to launch next week.

Furthermore, from our beginning, we have invited anyone to Request-A-Test on our Endo File Evaluator. Through this online form, anyone may submit ideas for additional protocols they wish to see performed on our Endo File Evaluator and we will be happy to perform them and publish the results, even if they prove unfavorable to our own designs. Our mission is to empower endodontic practitioners and advance their potential by offering the most effective products while providing open access to unbiased informational resources for instrumentation and design. What we seek is knowledge and what we hope for is your participation.

What differences do endo file design differences make?

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What differences do design differences make? We intend to find out. We are embarking on a very ambitious research program to test each part of every major file in production, from tip to handle. We have completely up-dated the computer controlled Endo File Evaluator to improve resolution of its sensors and motors and to expand its capability for performing new testing protocols. As such, we have created what I believe is not only the most objective means for evaluating endodontic files, but also the best method for testing file functions in a manner that is truly relevant within a clinical setting. We do this while letting the data determine the results for objective comparisons independent of operator skill or marketing bias.

What difference does this endeavor make? Our first objective is to finally determine how to minimize risk and maximize efficiency, how file designs relate to function, how function relates to canal anatomy, and how anatomy relates to technique. Our second objective is to present the Endo File Evaluator results using the numerous different parameters for testing, and to use high resolution images and SEMs in a manner that allows clinicians to save and apply the information to enhance their skill and treatment.

How will this process take place? About every ten days we will share test results and observations of only one segment of each file beginning with the file tips. Through this blog, we invite you to participate in discussions and critiques to create group research dynamics as this project progresses. Once all segments of the files have been covered, a composite of each whole file will be available as an endodontic reference along  with any contributing assessments gathered from our readers. We will continue providing results as we find them through this comprehensive series of evaluations and add to them in the future as needed. We are excited to embark on this endeavor and hope you will follow along and contribute your own thoughts and impressions.