Cents and sensibility

X-ray taken by Dr. HB Johnson circa 1939 (courtesy Dr. Tom McDonald, Atlanta GA)

X-ray taken by Dr. HB Johnson circa 1939 (courtesy Dr. Tom McDonald, Atlanta GA)

When preparing a root canal, there seems to be nothing that can’t be achieved by a skilled endodontist. In the right hands, virtually any root canal can be prepared with virtually any file or number of files. The very small curvature radius and large curvature angle in the featured x-ray illustrates the extraordinary skill for using carbon steel files in 1939 by Dr. H.B. Johnson, the individual that gave us the term “endodontics.”

Curiously, it is rare that a file is promoted today without an accompanying x-ray depicting an extraordinarily difficult case. Should we conclude then that all files will enable you to achieve ideal root canal preparations? We can eliminate almost all restrictions except for one, our inability to freeze time. Ahh… there’s the rub. Time is our most valuable commodity.

Many years ago, a clever sales rep showed me a time saving formula demonstrating the annual money savings that a very expensive digital x-ray device would provide before convincing me to buy what turned out to be the very first digital x-ray device sold in the US. Ever since, that formula has continuously convinced me that penny-pinching at the expense of saving time isn’t really saving money at all. It’s no different with endodontic files. Consider that by saving 10 minutes/patient with each of 6 cases/day for 200 days results in 5 weeks of chair time saved annually. That’s more than a month of additional production, vacation or whatever you like!

A file’s ability is not the issue. Rather, a file’s efficiency during performance is THE most important issues and our guiding objectives when designing NanoEndo files. Our results are extremely successful in this regard and our customers agree that NanoEndo’s highly efficient designs save them time and reduce risks during root canal preparations. See for yourself and review our comparisons with the files you are using now or give us a call (844.ONE.FILE) to learn more. Remember lost time can never found.

Is scientific hype replacing scientific evidence?



**Watch this VIDEO to see a brief summary on how results from our testing of file performance differs from conventional testing of flexibility and cyclic fatigue.**

Many endodontists have devoted a great amount of valuable time to endodontic instrumentation research using scientific evidence in an attempt to convey useful information for the advancement of endodontics. Scientific evidence relies on comprehensive data and it is crucial for researchers to ensure that the data they collect is sufficiently inclusive to have relevance to actual clinical situations. When “scientific hype” reaches the point that it diminishes the value of scientific evidence, then practitioners need to be aware that insufficient information can have counterproductive consequences.

During scientific research it is not uncommon to encounter hype. Although somewhat frustrating, common hype is usually tolerated because claims are at least somewhat true. Even though the benefits of the claims are usually exaggerated, they are transparently limited in scope. An example of such a claim would be: “These files are faster, safer, and require fewer sizes.”

What is apparent to the dentist is the missing ‘compared to what’ or ‘under what circumstances’. Taken alone, these claims are obviously discounted as scientific evidence. Recently, however, a more insidious hype, one that uses insufficient and selective scientific testing, has lead to erroneous conclusions and created an opportunity for mistakes. This type of hype uses the convincing nature of inductive reasoning that is not so apparent, but may be easier to recognize once it’s broken down into logical propositions. Consider the following examples:

From a specific proposition such as:
A file’s greater resistance to cyclic fatigue is better than less resistance to cyclic fatigue.

To a general proposition:
Greatest resistance to cyclic fatigue results in the best file.

This particular general proposition has gained widespread acceptance and success in the promotion of endo files. One company claims, “700% greater fracture resistance compared to traditional NiTi files” without stating that the increased resistance to cyclic fatigue was accompanied by a reduction in the resistance to torsional stress, an essential component of resistance to failure. Another company uses resistance to cyclic fatigue as evidence for “unmatched strength”, “Off the charts Strength,” “Amazing strength means the confidence…,” and “Twice the strength, half the cost.”

The definition of strength within the context of metallurgy is the resistance to deformation. Now consider that the files described above distort with the least force of almost all, if not all, of the files on the market. All other factors being equal, increasing the resistance to cyclic fatigue is concurrent with a decrease in file strength and resistance to torsional stress. Unwinding is evidence of torsional stress. The question becomes, as long as the resistance to cyclic fatigue is adequate, why compromise by reducing the resistance to torsional failure?EdgeVsOneEndo_Graphs

There are certain features of science that give it a distinctive character as a mode of inquiry. Once that mode of inquiry is compromised, It is no longer valid science. When a company claims that its file will rotate over 600 seconds in a 90 degree curvature 3mm from its tip, and that capability is two times as long as a competitive file, does it make it a better file? If it does, does that mean a copper wire of the same diameter that will rotate 1,800 seconds is the better file? Actually, it only means that it has better resistance to cyclic fatigue in that particular circumstance with no evidence for superior performance. Besides, who lets a file rotate 600 seconds in a 90 degree curvature? Or even 10 seconds? Is there relevance to actual clinical situations?!

The ultimate goal for instrumentation advancement can be stated as, ‘maximizing efficiency and minimizing risks while accomplishing the preferred results.’ How effectively that goal is achieved is a measure of performance. My hope is that you will scrutinize all claims of advancement to the best of your ability. That especially pertains to any claims that I might make. Scrutiny is the hallmark of advancement.


Limiting Torsional Stress on Endodontic Files: Lubrication, Irrigation and/or Technique


I was recently asked if irrigation and lubrication influenced the stresses a file undergoes during instrumentation. Research that I carried out indicated irrigation and lubrication can reduce torque requirements by as much as 400% compared to rotating in a dry canal. However, one can see from the included chart that the amount of the file’s engagement can be as important as the lubricant itself in reducing torsional stress. Shorter strokes of insertion is more effective in reducing torsional stress than carrying the rotating file to greater depth into the canal with fewer insertions. When the rotating file becomes engaged for more than a very few millimeters, the interface of irrigation is reduced between the surface of the canal and the file and torsional stress increases.


The importance of engagement is illustrated. Quantec files were inserted in 1mm increments at 1mm/s with a depth of 8, 10, and 12mm. The torque recorder is an average of 6 files taken for each depth. Note minimum engagement can have approximately the same benefit as irrigation in reducing torque.

Join Us for a Complimentary Seminar

The Efficient and Productive Endodontic Practice:  Dr. JohnT.McSpadden

If you save a penny and double it every day, it only takes 27 days to become a millionaire. We are familiar with the power of compound returns but sometimes the power of accumulative returns escapes us, particularly in our practice. Ponder this as an endodontist: If you complete 6 cases a day and if you save 10 minutes for each case for 50 weeks, you would “save” over 31 eight hour work days in a year. If not saved, perhaps “wasted” is a more accurate term.

I became so impressed with the accumulative returns concept that my practice became a laboratory for developing proficiency. That involved collecting ideas from scores of practices for over 40 years and designing over 30 patented files and techniques for efficiency to become one of the most productive practices in the nation. The potential gains when you maximize how efficiently you perform can be astronomical. Nothing, however, has given me more satisfaction than being able to learn from your and others’ expertise and to combine them with my unique experiences in the form of seminars.

We condense the NanoEndo seminar to 1 concentrated, full day for developing all aspects of practice efficiency, but especially on how files and preparation techniques can dramatically and uncompromisingly provide “accumulative” returns. Conversely, we point out that one might spend way too much time on things that don’t matter.

Our approach:

  • First an examination of the sequence of file development will be used to recognize what and why file features and seminar-imagetechniques constitute advantages and disadvantages.
  • Determine and test for time/risk benefits and limitations of any file and technique.
  • Determine when to use fewer or more files during canal preparation for results and time conservation.
  • Determine a file’s limitation and maximize its capability.
  • Determine the appropriate files and technique to use relative to the canal anatomy.
  • Determine how to minimize stress and maximize efficiency during canal preparation.
  • Discover how the files and techniques you now use compare with the alternatives while using the computerized clinical simulator.
  • Discover how to practice at the speed of thought; there are no “cookbook”step by step procedures.
  • Learn how to reduce the things that “don’t matter”.
  • Learn how to use a formula to identify and use “accumulative” returns in all aspects of your practice from the “hello to the goodbye” of patient treatment.

Our objective is not to tell you what to think or even being an advocate, but rather to help in making discoveries. We invite you to join us for the Nov.13, 2015 COMPLIMENTARY Seminar, but let us know soon to best accommodate you. Email or call us directly at 844.ONE.FILE (844.663.3453).

Our seminars are held in Chattanooga, Tennessee, one of the South’s top travel destinations. In fact, the New York Times named Chattanooga one of the “Top 45 Places to go” in the World.  Only four US destinations were named and the Scenic City was the only place outside of California.  And it’s no wonder, tucked away between the mountains of Southeast Tennessee and along the beautiful Tennessee River. We hope you will decide to bring your family and spend some time here. http://www.chattanoogafun.com/

If a picture is worth a thousand words, then what’s that worth?

X-ray taken by Dr. HB Johnson circa 1939 (courtesy Dr. Tom McDonald, Atlanta GA)

Most of the time x-rays of tortuous canals are used to demonstrate the capabilities of a file. This begs the question: exactly how much information do we get from an x-ray. Dr. HB Johnson, one of the pioneers of endodontics and the man who coined the term endodontics, is the person that performed the RCT of the featured x-ray taken around 1939. If we use this x-ray (courtesy of Dr. Tom McDonald, Atlanta GA) illustrating a successful end result as a benchmark, then we shouldn’t be so impressed with x-rays portrayed today as an indication of how good a file is. The files he used were carbon steel, worse than any file than most of us have ever seen. I’m including two x-rays of cases I completed soon after the introduction of NiTi rotary files. I cannot even remember which files were used, but probably not the ones I would recommend today.  The point is: virtually any file can prepare virtually any canal. More difficult to illustrate is the ease, predictability, and productive capability of a file. This is why our research focuses on determining endo file limitations and efficiencies rather than endo file abilities, given the time and skill of the operator.

NanoEndo and Stellar Studios Awarded Gold Communicator Award for nanoendo.com

NanoEndo is proud to announce its website, nanoendo.com, has been awarded a Gold Communicator Award from The Academy of Interactive and Visual Arts. The website was developed in conjuction with Stellar Studios, a multimedia marketing agency based in Johnson City, TN. The Gold Communicator Award falls within the Websites, Websites Visual Appeal category and recognizes nanoendo.com for its unique design characteristics and overall esthetic appeal.

“We really wanted to create something different that stands out from our competitors. My father and business partner, Dr. McSpadden, is distinguished as one of the world’s foremost endodontic file designers and he considers the One Endo file to be the best overall file design he’s ever seen. When we founded NanoEndo LLC to bring the One Endo file to market, I knew that our website would become the cornerstone of our efforts and I wanted its design to highlight the same uniqueness in thought and attention to detail evident in my dad’s instrument design. I have a long history of working with Stellar Studios to create award winning multimedia designs and it was a forgone conclusion that they would help us achieve our goals. Stellar Studios is an outstanding agency with tremendous talent and we are very fortunate to count them among our friends and partners.” – JT McSpadden, Chief Operating Officer, NanoEndo LLC

The Communicator Awards is the leading international awards program recognizing big ideas in marketing and communications. Founded two decades ago, The Communicator Awards receives over 6,000 entries from companies and agencies of all sizes, making it one of the largest awards of its kind in the world. The Communicator Awards is sanctioned and judged by the Academy of Interactive & Visual Arts, an invitation-only group consisting of top-tier professionals from acclaimed media, communications, advertising, creative and marketing firms. AIVA members include executives from organizations such as Airtype Studio, Big Spaceship, Conde Nast, Coach, Disney, The Ellen Degeneres Show, Estee Lauder, Fry Hammond Barr, Lockheed Martin, MTV Networks, Pitney Bowes, rabble+rouser, Sotheby’s Institute of Art, Time, Inc, Victoria’s Secret, Wired, and Yahoo!


What difference does unwinding an endodontic file make if it doesn’t break?

extrusion segI was recently asked why would it matter if an endodontic file unwound as long as it didn’t break. First, let us think of a file as not only an instrument that enlarges a canal but one that acts as an auger as well; it conveys debris. When a file unwinds to the extent that its helix augers apically rather than in a coronal direction (as in segment 1), then debris is extruded through the apical foramen. Note that part of the file becomes denuded. Post operative pain will most likely be the consequence. The unwound segment 2 continues to auger debris in a coronal direction while the unwound segment 3 augers in an apical direction. The result is compression of debris, additional torsional stress and a greater propensity for breakage. Keep in mind most files will not even unwind 2 revolutions without fracturing. If the file is rotating 500rpm, 2 revolutions require less than 1/4 second before failure.

The short answer to the question is: it probably matters. Luck is not nearly as predictable as cause and effect.

Maximizing Efficiency – for what it’s worth


Time is the one commodity shared equally with all. No matter who we are or where we are we each get 60 minutes with every hour, 24 hours each and every day and then it is gone forever. One cannot keep time from passing, yet, profoundly, one can save time.

Early in my career, I had the good fortune to enroll in a course on ergonomics. The curriculum was about efficiency and how best to streamline all the individual movements and methods used to complete a procedure. This concept resonated with me and guided my thinking and methods throughout the rest of my career. In fact, my endless pursuit of efficiency within my own practice is what ultimately inspired me to design and modify my own instruments and techniques.

Even very small gains in efficiency will compound over time and can have a profound impact on a practice over the course of a career. Suppose you could save 10 minutes with each patient. If you see only 6 patients in a day, that would equal an extra hour each day; 5 hours each week; 260 hours each year. That’s the same as 32.5 eight hour working days a year! Can you imagine that a simple 10 minute gain in efficiency might result in gaining an entire month’s worth of time over a year? What is the value of such a proposition? Keep in mind that there is a big difference in saving time and wasting time.

In my practice, I bought and tried every new gadget that came to market, always searching for new ways to save time and effort. Mine was one of the first practices to use digital x-rays, electric handpieces and a microscope. Later, I introduced a NiTi rotary file simply because I knew it would make me more efficient. Ultimately, I became so efficient that I had even more time to seek out even greater efficiencies and now that I’m retired from practice, the fascination remains.

The One Endo file’s design was born from my unending pursuit of maximizing efficiency in instrumentation and my research continues to validate that combining two or more dissimilar tapers side-by-side within the same instrument, significantly enhances virtually any endodontic file design. Recently I was asked to describe why an established practice should consider switching file systems to incorporate the One Endo file in terms of a return on investment. Addressing any ROI demands that benefits are quantified, so I turned to data from our research for insight.

What I found when taking a very broad view for comparison was striking: the One Endo file is 33% more efficient on average than every other file we’ve tested to date. This number is a comparison of the average maximum torque and pressure values from all files and sizes tested with our Endo File Evaluator against the same parameters for all sizes of the One Endo. More importantly, it should be noted that half of our competitors’ files failed their respective evaluations resulting in broken/distorted tips or screwing into or transporting the canal.

While this finding does not mean that switching to the One Endo will save you 33% more time or money, it does mean that it is very likely to allow you to complete the same amount of work with less effort. Depending on how you adapt your technique to incorporate such a gain in efficiency, this could result in time/money savings, but most importantly, it is likely to improve your results. This poses a new question: If you can become more effective by using a new file, why wouldn’t you try it? Remember that 10 minutes I saved way back when? Consider this – at the end of my 31 years of practice, those 10 minutes managed to free up over 2.5 years of extra time! Granted, I can’t tell you where that time went, but it wasn’t wasted and I loved every minute of it.

On Communication and Collaboration for Advancing Endodontic File Design

While the overwhelming majority of comments we receive regarding our research and innovations is very positive and complementary, publishing our independent research while marketing our own endodontic file designs and claiming unbiased objectivity opens us up to criticism and scrutiny. We expect and welcome such skepticism as it inspires discussion and informs further investigations. Our hope is that our openness to criticism and our transparency in operations will ultimately serve to balance biases and provide an open dialogue wherein all perspectives may be granted equal consideration. To that end, please consider the following comments we’ve received regarding our most recent series of endo file evaluations alongside our responses to them:

Alex’s Comment: (background unknown)

Great job Dr. McSapdden! Your experiment’s design proved that your file is the best! Well done!! Now it’s time to put together an experiment to prove that your children are the cutest!! Come on man! Is this a joke? How can you sell a file and test competitor files? Well. Thanks for wasting my time reading this commercial.

Dr. McSpadden’s Response:

The instant formula for failure may be to try to please everyone but we try. We try by using equipment that can give results that can be consistently replicated independent of the operator. We try with a commitment to publishing the results without knowing in advance what the results will be. We try by inviting any change in the parameters we use for testing as well as inviting anyone to observe the results as they occur. We try by including 35 years of our past testing experience to provide the most useful information we know how. We try by using the information we have accumulated to design instruments that might help in providing solutions for clinical needs. We try by having our quest for solutions to be a continuing endeavor. We try by convincing ourselves that trying is better than doing nothing when success is unknown but that even failure might be at least some benefit. And, we will try to help you find solutions if you should ask and hope that you might try to do the same for us. And, yes my grandchildren are the cutest and, as a 75 year old grandfather who doesn’t need to sell files, I will admit that particular claim might be biased.

David Clement’s Comment: (UTHSC Grad Endo)

This is a great project you are sharing with the Endo Community.  I look forward to seeing further results which you say will be distributed regularly. Just one comment, and perhaps a description criteria you could consider adding to the Descriptive Characteristics. The Circular core dimension as a percentage of the circumferential size (diameter) would be a very interesting characteristic to see.  The bulk of metal in the core (Not including the exposed cutting edges) could give fundamental information/understanding on torsional strength and and Cyclic fatigue characteristics of these rotary files.  It would also give information is the core area changes in the length of the blade, theoretically increasing the Flute space ( debris removing area). Again, Many thanks for sharing the project information with us. 

Dr. McSpadden’s Response:

…I think your idea is excellent. It might be good to carry it a step further and have the core as a percent of the total x-sectional area. If we cannot change the program easily I can include it in the discussion. I really appreciate your interest and comments.

If you have any questions or comments of your own, please feel free to share them with us however you like. Post them here, send us an email or give us call (844) ONE-FILE [663-3453]. We value your input and perspective and hope you will help us in collaborating for the advancement of endodontics.

One Endo : Tip Evaluation (1st 3mm)


WEBSITE: nanoendo.com



SIZE: 25/04
FLUTES: 2 (S-shape, H-type)
HELIX ANGLE: 7.5º [fig. 2]
CUTTING ANGLE: (-) 40º [fig. 1]
60 ̊ DEFLECTION: 3.56 g



  • The degree rotation to failure is less than that for the Edge file or the ESX.
  • The peak torque at failure is more than the Edge but less than the ESX.
  • Interestingly, the One Endo was not superior in either the rotation to failure or deflection tests but was the only file that did not fail the Endo File Evaluator protocol. This is likely due to the One Endo’s blade that extends closer to its actual tip and the single blade opposed by a rounded surface and its reduced helix angle. These features facilitate greater efficiency in debris removal.




Fig. 2