Responding To My Critics Here On Linkedin

One critic states his objection to my comments regarding the balanced force technique and I am quoting his remarks. “Incorrect. The Balanced Force method, with K-files, followed canal curvatures better than any other filing technique, without packing debris, and produced the least amount of debris extrusion. Push-pull packs and extrudes debris.

Your push-pull method is nothing like the Balanced Force method. Once again.”

My response to his comments is that the design of the K-files used in the original paper on balanced force is an excellent flute configuration to impact debris apically. The flutes on the K-file are predominantly horizontally oriented. When used with the balanced force technique the initial 90o clockwise arc of motion embeds the flutes into the canal wall. That motion is followed by a 270o counterclockwise motion while at the same time applying apically directed force to prevent the flutes from unscrewing disengaging the flutes from the canal wall. The result is a cleaving of the engaged dentin from the canal wall with the debris filling the depth of the flutes.

This debris must be removed from the flutes for further penetration of the length of the canal requiring a coronal pull stroke out of the canal to physically cleanse the instruments. This same instrument or the next larger size is then inserted to depth using a push stroke at which point the predominantly horizontal orientation of the flutes are well-designed to impact any debris present apically. Dentists know that in the establishment of a glide path too often there is loss of length in the apical third due to the impaction of debris resulting from the use of the K-files. So, while the balanced force technique can advance the instruments without apical distortion, the potential to impact debris with loss of length is a direct result of the predominantly horizontal flute orientation. Another point to consider is the fact that upon withdrawing the instrument from the canal for cleansing, those same horizontal flutes are tending to shave more dentin from the inner wall of a curved canal resulting in some degree of canal transportation.

The key to the significant reduction in distortion is not based on the design of the K-file, but its use with short arcs of motion. Indeed, the balanced force technique is effective despite the use of the K-file. By substituting relieved stainless steel twisted reamers used with an even shorter arc of motion the ability to debride curved canals without distortions is further enhanced. Why is this so? The flutes on the reamers are predominantly vertically oriented. Consequently, when an arc of motion is applied that is more or less at right angles to the cutting edge of the flutes, that motion shaves dentin away from the canal walls. Where the short horizontal clockwise motion used in the balanced force technique embeds the flutes into the dentin, the flutes on the reamers immediately shave the dentin away with the equally short counterclockwise motion cleaving off any residual dentin that might still be engaged. Whether reamers or files are used, in either case the instruments must be withdrawn to remove the debris from the depth of the flutes. As noted above, while the horizontal flute orientation of the K-files tends to shave dents away from the outer wall of curved canals on the out stroke and debris impaction on the in stroke, the vertically oriented flutes on the relieved stainless steel reamers are poorly designed to shave dentin away on the pull stroke and also poorly designed to impact debris on the in stroke, making the reamers function in a more efficient way considering what we want to accomplish.

If one understands what the balanced force is designed to accomplish, it becomes obvious that relieved stainless steel reamers are a better choice than the use of K-files . Hopefully, this more detailed explanation brings greater clarity to the subject.

Let me now address the remarks of another critic who I now quote. “The ONLY instrumentation concept that you have correct is that stainless steel is resistant to separation. Science has shown ALL the rest of your statements are merely fantasies in your mind. Of course you are unwilling to be shown wrong by scientific investigation of your claims. Though you cry out foul when science shows you wrong and you call it bias against your fantasy claims. You claim physic terms you do not understand as proof of your instrumentation claims. When confronted with realities scientific facts that don’t agree with you claim bias stating that companies are paying off the faculty to give false reports. I have given you an opportunity to have you claims scientifically investigated and you refused to support the research. You are afraid that you will be proven wrong and lose money by be shown wrong.”

He starts out by stating that indeed the stainless steel instruments are more resistant to separation. That is not exactly accurate. Confined to short arcs of motion even at high frequencies the stainless steel relieved twisted reamers are completely invulnerable to instrument separation. That’s 100%, 100% of the time, not merely more resistant to separation. That is not a trivial advantage. Now common sense dictates that 100% invulnerability to separation might include other advantages, namely, the ability to apply these instruments vigorously against all the canal walls while activating the ever present irrigants that are driven into intimate contact with these canal walls. This fact was corroborated from our own cross-sectional studies as well as the often referenced French study that documented the 30o oscillating stainless steel reamers as the only system that removed the smear layer from the entire length of the canals compared to three other rotary systems.

He states my criticism of claims of bias and corporate influence is something I conjured up in my head. On the contrary, and unfortunately, corporate influence has been well-documented and I am quoting particularly one study published in the official ADA journal that concluded that 80% of academic endodontists are the recipients of industrial payments. Why would they publish an article that is so detrimental to our own profession unless they hoped by publishing it that it would lead to reforms, greater transparency and an impetus for a more honest platform for unbiased teaching and research. Given his lack of concern on this issue and conducting himself in a way that to the casual observer does not represent an unbiased temperament, his offer to supply a source of impartial judgement is met with a bit of skepticism on my part. As I’ve said before, I may have been born at night, but not last night.

Now getting back to instrument separation, while there are a multitude of studies that the compare varying degrees of debridement, distortion, apically extruded debris none of these factors have been shown in any studies to effect success rates. Indeed, the only factor that has been documented to effect success rates is the separation of an instrument in a non-vital tooth with an area. So, the fact that a technique is available that prevents instrument separation 100% of the time is worth knowing about. That it is one that is engine-driven from the start bypassing the need for the manual creation of a glide path minimizing hand fatigue and reducing procedural time requirements are qualities that at a minimum equal the efficiencies of rotary NiTi without the concerns for instrument separation and the advantages that derive from that fact.

I do take a certain pleasure in attempting to provide rational responses to what I interpret as attempts to degrade what I say as well as my person. My ultimate refuge are the endodontic workshops we provide, contributing information that is simply not attainable in any format that is based on marketing rotary NiTi be it used in a continuous or interrupted manner. In this environment I meet dentists who wish to improve their endodontic results, including safety, effectiveness and efficiency. I state my case and then given them the opportunity to decide for themselves whether or not the claims I am making are supported by their experiences. The dentist is the ultimate judge and that judgment is enhanced with his/her exposure to the widest range of methods available. My job in the workshops is made easier by the fact that the vast majority of participants are already well versed in the various rotary methods available. What they were never exposed to during their formal dental education are solutions that overcome all the shortcomings of what they were taught in school where there was no exposure beyond what the corporate sponsorship offers. Nothing beats being well-informed.

Regards, Barry