Is scientific hype replacing scientific evidence?

EdgeVsOneEndo_Pics

 

**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.

 

Conventional Research: Greater Value than Actuality?

Screen Shot 2015-11-09 at 9.08.49 AMAfter so many years of research, it is daunting to succumb to the realization that so much of my time was devoted to compiling conventional, or what could be considered useless, data for evaluating endodontic files. Someone once commented, “There is no ox so dumb as the orthodox.”

For instance let’s consider a file that is statically in the 50 percentile compared to other files in resistance to cyclic fatigue and also in the 50 percentile (50/50) in resistance to torsional failure. Research will reveal that files that are in the same percentiles can perform very differently. Compiled data for these percentiles might give little indication as to how a 60/40 percentile would perform  or a 40/60 percentile. Certainly a 100/? percentile can amount to little more than hype. There are too many other design differences to consider for extrapolating for conclusions.

My realization from the research I have experienced is, file features should only be considered file features with no indication of how the file will perform until performance itself is measured. Only then, should we attempt to explain the performance in terms of the file’s features. We can use the “ox“ depiction again to represent the paradox of Schrodinger’s cat; we have to see the results first to explain them and then our explanations might actually be very comprehensive.

Fortunately, we at NanoEndo have conducted literally 100s of file evaluations measuring performance, probably more than all other performance evaluations put together. And, fortunately, you do not have to depend on projections. NanoEndo files speak for themselves; their performance excels beyond comparison. We invite you to see for yourself.

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/

ProTaper Next : Tip Evaluation (1st 3mm)

ProTaperNextX2Full

DETAILS:

FILE NAME: ProTaper Next X2
COMPANY: Dentsply Tulsa Dental
MANUFACTURER: Dentsply Tulsa Dental
MADE IN: USA
WEBSITE: tulsadentalspecialties.com

 

CHARACTERISTICS:

SIZE: X2 (.25 tip/0,04-1.2 taper)
FLUTES: 4 (rectangular)
SPIRALS PER 16MM: 3
HELIX ANGLE: 18.5º [fig. 2]
CUTTING ANGLE: (-)45º [fig. 1]
DEBRIS REMOVING AREA: 46.4% [fig. 1]
ROTATION TO FAILURE: 640º (bound 5.7mm from tip)
PEAK TORQUE AT FAILURE: 10.42 gf/cm
60 ̊ DEFLECTION: 3.97 g
PLASTIC DEFORMATION: 0º
FILE CORE AREA RELATIVE TO CIRCUMFERENCE AREA: 42.9%
FILE CORE AREA RELATIVE TO FILE X-SECTION AREA: 78%

 

DISCUSSION:

  • Since the x-section is rectangular, the cutting angle meets the surface to be cut at a 45 degree angle and one might expect very little canal enlargement to occur. However, cam action resulting from the center of rotation being different from the center of mass enhances its cutting ability. Near the tip end, the file’s relatively small core area as compared to its x-sectional area and circumference, makes it more susceptible to separation (especially when sufficient torque is applied for enlargement at its midsection and handle end).

    Tip SEM

    Fig. 1

    Fig. 2

    Fig. 2

     

     

     

     

     

     

     

    SEMs are provided by Dr. Franklin Garcia-Godoy, Professor and Senior Executive Associate Dean for Research Director, Bioscience Research Center University of Tennessee Health Science Center

     

Maximizing Efficiency – for what it’s worth

TimeManagement1

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.

Descriptions of Protocols and Terminology

Rake & Cutting Angle:
If the file is sectioned perpendicular to its long axis, the rake angle (cutting angle) is the angle formed by the leading edge and the radius of the file inscribed in its circle of rotation. While using the radius as the line of reference, if the leading edge is in front of the perpendicular radius, it is referred to as a negative (scraping) cutting angle and is measured as the angle formed by the leading edge and radius. If the leading edge is behind the radius, it is referred to as a positive cutting angle.

Negative Angle

X-Section with Negative Angle

X-Section with Positive Angle

X-Section with Positive Angle

 

 

 

 

 

 

 


 

Circumference Area & Core Area:
The circumference area (A=3.14r²), inscribed by the rotation a file, is determined by defining r as the distance from the file’s central axis of rotation to the file’s outer most boundary. The core area of the file (A=3.14r²) is the cylindrical center area of the file having its circumference outlined and bordered by the depth of its flutes. It should be noted that there are instances when the central axis of rotation is separate from the file core’s center.

File with symmetrical X-section

File with Symmetrical X-Section

File with Asymmetrical X-Section

File with Asymmetrical X-Section

Circumference&AreaKey

 

 

 

 

 

 


 

FLUTES & SPIRALS:
The flute of the file is the groove in the working surface used to collect soft tissue and dentine chips removed from the wall of the canal. The surface having the greatest diameter that follows the groove (defined as where the flutes intersect), as it rotates, forms the leading (cutting) edge. The number of spirals that a file has in its working surface can be calculated by dividing the number of flutes on the working surface by the number of flutes in  x-section.

Sides of X-Section Point to Corresponding Flutes

Sides of X-Section Point to Corresponding Flutes

 

 

 

 

 

 

 

 

 


 

HELIX ANGLE:
The helix angle is the angle the blade makes as it intersects with central longitudinal axis of the file.

Helix Angle

Helix Angle

 

 

 

 


 

DEBRIS REMOVING AREA:
The debris removing area is the total flute space represented as a percentage of the circle area that inscribes the file.

DebrisRemovalArea

 

 

 

 


 

DEFLECTION & DEFORMATION:
Deflection is measured as the file is lowered 5mm onto a 60 degree incline. If the file remains bent as it is lifted from the incline, the angle of the bend is measured as plastic deformation.

Deflection

 

 

 

 

 

 

 


 

ROTATION TO FAILURE:
To determine rotation to failure, 3mm of the tip end of a file is locked into place before rotating its handle end continuously until it breaks. The degree of total rotation is measured at the point where the file fails.


 

PEAK TORQUE AT FAILURE:
Peak torque at failure describes the maximum torque the file undergoes as it is rotated to failure.


 

 

 

Introduction to Mastering Endodontic Instrumentation : An online addendum

Screen Shot 2015-02-04 at 7.24.00 PM

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.

 

DOWNLOAD MASTERING ENDODONTIC INSTRUMENTATION (original award winning text)

 

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

CardCheat

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?

Screen Shot 2015-02-04 at 7.24.00 PM

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.

Sample Selection: How we select files for evaluation on the Endo File Evaluator

Screen Shot 2015-01-21 at 6.47.36 PM

In any scientific study that intends to make inferences about an entire production of endodontic files its primary objective, the sample size is a very important feature for having sufficient statistical power. In estimating unknown parameters, larger sample sizes generally result in greater statistical confidence. Unfortunately the clinician rarely has that opportunity. If he uses 10 out of 100,000 files, that’s only a 0.001% chance that all of the others are the same. He relies on the manufacturing regulatory procedures for confidence in using every single instrument as 1 in 100,000 or the production number. In other words, the clinician relies on the one that comes out of the box. In our evaluations and in our imaging we make the same sample selection as does the clinician, the one that comes out of the box. With that selection we make the ethical commitment that every image we show and every test we conduct is unaltered and as independent as possible from operator influence.

Recently we received a complaint from Komet that the SEM we received from NOVA University and featured in a previous blog was not representative of their files. Their claim may be entirely valid. One out of the box may not be a representative selection but it is the selection upon which the clinician relies. If Komet would like to provide us with us with a statistical analysis and standard deviation of what is representative, we would welcome the opportunity to post their analyses and images.