Beyond Marketing: Critical Thinking As Applied to Stainless Steel Relieved Twisted Reamers

I have been repeatedly described by the two critics on linkedin as simply a vendor who will do anything to sell the instrumentation systems we developed as an alternative to rotary NiTi instrumentation. So, lets address those accusations with critical thinking. Reality: Rotary NiTi is increasingly subject to instrument separation as canal anatomy becomes more complex. To deny that is to be blind to the research studies that are still being published up to the present day that confirm this fact. Given its unpredictable tendency to break it is simply logical to seek instrumentation systems that are invulnerable to separation. An excellent proven way to prevent breakage is to confine the arc of motion to 30º or 1/12 of a full rotation. It is a fact that stainless steel relieved twisted reamers do not break when confined to 30º arcs of motion even at frequencies of 3000-4000 cycles per minute regardless of the degrees of curvature they are negotiating through. So, we have two established facts: Rotary NiTi is prone to breakage and 30º oscillating stainless steel relieved reamers are not. This point alone addresses the major shortcoming of rotary NiTi.

The literature clearly documents the inadequate debridement of oval canals when using rotary NiTi logically resulting from the fact that it is strongly suggested to use these instruments in a light centered way to reduce the incidence of instrument separation. The 30º oscillating relieved twisted stainless steel reamers are not subject to such limitations and are, consequently, applied vigorously against all the canal walls. This is a major difference between the way the two are applied within the canals. It defies common sense not to conclude that a system applied vigorously against all the canal walls will not do a more thorough job of debridement compared to one that must stay centered in oval canals.

Regarding the issue of canal distortions: Prior to the introduction of rotary NiTi, Dr. James Roane’s development of the balanced force technique demonstrated that stainless steel K-files negotiate curved canals without inducing distortions. The key to non-distortion in this technique is based on short arcs of motion generating a degree of stress against the canal walls that is less than the resistance of the canal walls causing the instruments to deflect when the two meet. Such deflection results in the instruments following the path of least resistance, namely, the patency of the canals. The 30º arcs of motion used in our approach are significantly smaller than those employed in the balanced force technique further reducing the stresses the instruments apply to the canals and, consequently, deflect more efficiently than the K-files. This is further aided by the fact that relieved stainless steel twisted reamers are more flexible than comparably sized k-files. The K-files are applied manually in the balanced force technique while the 30º oscillating stainless steel relieved reamers are run at a frequency of 3000-4000 cycles per minute making it a much more rapid system eliminating hand fatigue in the process. The high frequency has no impact on the canal walls other than shortening the time requirements. If some disagree with this position, please explain.

So, up to now, we are presenting an alternative to rotary NiTi that is invulnerable to breakage, cleanses canals better, has no greater potential to distort canals and being engine-driven from the beginning is time efficient. Added features derived from common sense: Instruments confined to short arcs of motion are less likely to induce micro-cracks. These instruments, given the way they are utilized, are invulnerable to breakage. According to Newton’s Third Law of Motion, two interactive bodies have an equal and opposite impact on each other. A reasonable conclusion is that instruments that don’t break are less likely to induce micro-cracks than systems that are vulnerable to breakage. This relationship is confirmed in the dental literature where it is expressly stated that those systems imparting short arcs of motion are least likely to induce dentinal micro-cracks. Yes, in terms of critical thinking, I have to take into account the few studies that state rotary NiTi produced better debridement and less canal distortions compared to the 30º oscillating stainless steel reamers, but those studies are not corroborated clinically. Indeed, without any signs of canal distortions the 30º oscillating reamers produce debridement that is extended to all the canal walls. It would also be naive in applying critical thinking not to be aware of the bias that is introduced where corporate sponsorship not only determines what is taught in the schools, but also funds a good deal of the research that occurs in these same institutions.

The two critics who define me as vendor beyond all else, take no account of the fact that I am still a practicing endodontist for over 52 years, have hundreds of papers published in juried journals and teach exactly the techniques I have adopted in my own endodontic practice. The fact is none of that should matter and any comments on my reasoning should also be limited to critically analyzing the data both academic and clinical and give cogent reasoning why my interpretation is unreasonable. Time and again, I have asked the critics for specifics in why what I am saying is wrong and evidence that the weaknesses associated with rotary NITi are not accurately described.

If one looks at their responses, they have a lot more in common with the marketing tactics they accuse me of, a complete avoidance of undesirable topics such as instrument separation, dependence upon the few papers that support their preferences, a whole host of personally degrading remarks and no comments on the overwhelming evidence of corporate sponsorship and its impact on the educational process.

Regards, Barry