Conflict In Data In Determining The Effectiveness of Various Endodontic Instrumentation Systems

The discussion on linkedin to date has centered on a comparison of rotary NiTi systems to engine-driven 30o oscillations of stainless steel relieved twisted reamers. The critic, an advocate of rotary NiTi presents studies that conclude that rotary NiTi produces superior debridement and fewer distortions. I offer data that includes thorough debridement of the mesial canals of a transparent 3D printed molar as well as the isthmus space common to both canals. In addition, I included a French study that showed superior debridement of the oscillating reamers over three rotary systems. I reinforced that data by showing cross-sections if highly oval canal anatomy that display no residual pulp tissue after instrumentation and obturation. To substantiate the oscillating reamers effectiveness in non-distorted shaping I have placed a number of cases with highly curved roots that display no apparent distortions in their preparations.

So, what we have is conflicting data. Yet, there is a difference in the data presented. The data I present is all visual clearly showing more positive results for oscillating reamers in debriding complex pulpal anatomy. The studies the critic references include data that is no longer relevant, a result of testing instruments that are no longer used in the 30o oscillating technique, because they, in fact, did lead to distortions in curved canals. Whatever such testing showed, it does not reflect the way the oscillating reamers are used today.

Regarding thoroughness of debridement, to accurately assess their effectiveness each system should be used to their full potential. In the case of rotary NiTi, the instruments to minimize their chances of separation, are used in a centered fashion with little lateral movement. This type of preparation is adequate in conically shaped canals, but leaves increasing amounts of residual pulp tissue and bacteria as canal anatomy becomes more oval and the presence of isthmuses increase. Centered shaping cannot avoid these inadequacies in three-dimensional debridement as canal anatomy becomes more complex as has been so noted in numerous research papers.

That fact produces a question that must be asked when comparing rotary NiTi to 30o oscillations of stainless steel relieved twisted reamers. Are the limitations of centered shaping that are a requirement for rotary instrumentation imposed on the oscillating reamers in these comparative studies? This question is crucial because what is a necessity for rotating NiTi is a needless impediment when employing 30o oscillating reamers. Used vigorously against all canal walls does not increase the chances of instrument separation and, consequently, should be applied in this fashion for superior debridement. Yet, for uniformity sake in a comparative study, not taking note of the freedom oscillating reamers afford the dentist in being vigorously applied to all canal walls via lateral application of the instruments and keeping them centered as is the case for rotary NiTi, produces results that don’t reflect this important advantage 30o oscillations of stainless steel relieved reamers have over rotary NiTi.

This last point is simply more in line with common sense. How is it possible for an instrumentation system that must stay centered and has been shown to leave as much as 50% of the pulp tissue in oval canals producing superior results to a system that can be aggressively applied to all canal walls. Such results don’t pass the common sense test. Assuming the studies the critic references are done with the best of intent, those doing the studies should be familiar with the best way to employ the systems. This is not obvious from the protocols or the results. The design of the protocols should reflect the most effective way they are used.

With the November 2021 article published in JADA that documented the fact that 80% of academic endodontists receive industrial payments, we cannot be so naive as to dismiss the possibility that much of the published research is used as a marketing tool to stifle the attractiveness of an alternative instrumentation system that overcomes the shortcomings of rotary NiTi instrumentation. How do we know that research is not only properly conducted, but is not under the influence of corporate manipulation particularly when it is an established fact that 80 of academic endodontists receive industrial payments? This fact alone, throws into question the results of comparative research studies that are then used as marketing tools.

The dental schools are responsible for this state of affairs. They have chosen not to prohibit corporate financial incentive. Indeed, the determination of what instrumentation system to teach the students is based on which corporation provides the most generous financial incentives. The schools have adopted the same mentality of the corporations, namely, maximizing profits. In that light, the students are now thought of more as consumers than students where the stated goal of increasing their critical thinking skills are supposed to be the basis of an educated individual. That goal has been sacrificed on the alter of academic capitalism, a state of affairs that will only lead to a further degradation in our educational institutions.

Regards, Barry