Just What Is Old Endodontic Technology

Recent commentary by a dentist on linkedin has suggested that I stop talking about the alternative method of instrumentation that I favor, namely, high frequency 30o oscillations of stainless steel reamers, and move on to the modern world of advanced rotary NiTi instrumentation. That the only reason I persist is because I have a financial interest in the sales of this alternative approach. That is not an accurate appraisal of how I got to where I am. It actually started with my purchasing rotary systems that caused me to experience instrument separations. Not that that had not occurred when I was manually using stainless steel instruments. The significant difference between the two experiences is that I knew by using short manual arcs of horizontal motion I could pretty much eliminate instrument separation as a concern unlike rotary NiTi that despite using a light pecking motion would on occasion cause instrument separation regardless of the precautions I took. The unpredictability of being unable to absolutely avoid separations made all the difference in the world to me. For sure I wanted a system that was totally invulnerable to breakage.

And that is precisely what 30o oscillations of relieved stainless steel reamers provides for. To get some appreciation of why this works consider the fact that a 30o arc of motion is 1/12 that of a full rotation subjecting the instruments to 1/12 of the stresses that fully rotating instruments encounter. The two stresses that cause rotary NiTi to break are torsional stress and cyclic fatigue. In both cases, instruments confined to 30o arcs of motion encounter 1/12 the torsional stresses and cyclic fatigue that fully rotating instruments encounter. Rotary manufacturers are fully aware of this fact and have introduced reciprocating systems that still produce full rotations, but interrupt them with a 30o counterclockwise motion. That reduces without preventing the breakages that unpredictably occur. It does, however, point out that the rotary manufacturers themselves understand the benefit of shorter arcs of motion.

Manufacturers of rotary instruments and their advocates cannot make a convincing argument regarding the superiority of rotary NiTi based on its increased vulnerability to separation compared to 30o oscillating stainless steel relieved reamers. Given the precaution of centered shaping that rotary NiTi users must employ to reduce separations also reduces their ability to adequately debride increasingly oval canals as well as thin isthmus spaces something amply documented in the endodontic literature. On this basis, superior debridement is not a fruitful area of comparison. So, the argument that the greater flexibility of NiTi results in a lower degree of distortions than 30o oscillating stainless steel relieved reamers is pushed as a superior factor. At first blush, this makes sense considering the higher flexibility of NiTi compared to stainless steel. What is completely avoided in this comparison is the information derived from the balanced force technique that clearly demonstrates fidelity to canal anatomy even with stainless steel instruments, if these stainless steel instruments are confined to short arcs of motion.

The lessons learned from the balanced force technique clearly tell us that stainless steel instruments confined to short arcs of motion are at least as effective as rotary NiTi in minimizing canal distortions. The potential for distortions is further reduced by using instruments more flexible than the K-files used in the original paper, confining them to even shorter arcs of motion that further reduces their potential for distortion with the added bonus of being engine-driven eliminating hand fatigue and reducing procedural time requirements.

The non-distorting benefits of employing stainless steel instruments with short arcs of motion are disputed in some research papers, but only to a minor degree. Two questions arise from these papers. Do the small differences in distortion really matter clinically. There is no paper that discusses the correlation of these small differences in the degree of distortions and success rates. The only areas where instrumentation and clinical results correlate is in those situations where instruments have separated in non-vital cases and the poor debridement of oval canals both associated with rotary instrumentation be it continuous or interrupted. The second question is far more difficult to answer because the papers anointing rotary NiTi as superior are also produced in institutions that have accepted corporate sponsorship of the rotary systems that are often the subject of comparative studies. So, discussions on the impact of corporate sponsorship are a delicate subject and open to highly charged emotions.

Rotary advocates state the concern for instrument separations are minor, a belief that is not substantiated by the separation cases we see posted right here on linkedin. Nor is it confirmed by the dentists who take our courses and are seeking solutions to this shortcoming. So, when a rotary advocate states that what I am posting is simply a means to draw attention to the alternative approach of 30o oscillating stainless steel reamers for commercial reasons, he is being simplistic ignoring the search I personally experienced in seeking safer, more effective and more efficient means of endodontic instrumentation in my own practice.

I don’t think I am any different from any dentist or endodontist who wants to do his endodontic procedures in a manner eliminating as much as possible the procedural stresses while not compromising the final results. Admittedly, I was most open to the solutions that we came upon, but that is only as a result of having to the best of my ability an open-mind not succumbing to the ubiquitous marketing efforts that have gone into the selling of rotary NiTi systems. Today, if anything the cases I treat are often more difficult because my referral base tends to consist of older dentists and their older patients. I would estimate the average age of the patients I treat to be about 70. When I see a younger patient I am eternally grateful.

The other day I treated a patient with a fairly curved mb canal, clearly seen in the trial fit. This is a reasonable example of the stainless steel reamers clearly negotiating curved canals without any sense of canal distortions. If there is some increased degree of distortions compared to rotary NiTi, something undetectable, it is more than compensated for by the more thorough means I can employ to debride in three-dimensions and the reduction in procedural stress because I am assured that the instruments will remain intact. Below is that case.

So, I won’t stop writing about the merits of our approach, engine-driven 30o oscillations of stainless steel relieved reamer compared to rotary NiTi. To do so would be to negate the techniques I have been using for the past couple of decades that have derived from the problems rotary NiTi forced me to encounter. There is another very human reason I won’t stop writing and talking. The people who approve of what I write far outnumber those who are not only critical of what I write, but also show no inhibitions in attacking my character and motivations that according to them are limited to selfish commercial rewards. Lucky for me, that the feedback I get from those who have taken our courses give me much psychic support and energizes me enough to have the motivation to not only continue, but to carry this message of alternative means with joy, excitement and commitment.

Regards, Barry