Issues Where GPT-4 Brings Clarity

When addressing the specific issues regarding the mechanics involved in endodontic instrumentation GPT-4 clearly discusses the advantages of 30o oscillations of stainless steel relieved reamers at frequencies between 3000-4000 cycles per minute. The 30o short arcs of motion generated by the oscillating handpiece exert far less pressure on the canal walls than fully rotating NiTi as well as the interrupted rotations defined as reciprocation. Furthermore, the instruments themselves are subject to far less stress for the same reason, eliminating the concerns of instrument separation associated with rotary NiTi. The short arcs of motion are the reason 30o oscillating stainless steel relieved reamers even at high frequency don’t break and don’t tend to induce dentinal micro-cracks, consistent with Newton’s Third Law of Motion which if you have read my past posts you are familiar with.

It is also a fact, discussed by GPT-4 that the shorter the arc of motion, the less the pressure exerted by the instruments on the canal walls given a constant amount of apically applied pressure. This particular mechanical principle results in a force applied to the canal walls by the instruments that is less than the resistance of the canal walls. In a curved canal, an instrument confined to 30o arcs of motion will deflect into the path of least resistance when the tip of the instrument contacts the canal walls. It is this particular principle that accounts for the fact that confined to 30o arcs of motion the relieved stainless steel reamers stay true to the canal anatomy while also not having to be concerned about instrument separation and the less observable dentinal micro-cracks that are produced via rotary NiTi instrumentation.

GPT-4 notes the advantages that the increased flexibility of NiTi brings to the table, namely, being able to use them in a rotary fashion even in significantly curved canals. Remaining true to canal anatomy is accomplished in rotation when using flexible rotary NiTi. The same ability to instrument curved canals without distortions is accomplished by employing relieved stainless steel reamers confined to 30o arcs of motion.. They are both engine-driven, but limited to 30o arcs of motion the stainless steel relieved reamers are not subject to excessive torsional stresses and cyclic fatigue that can lead to instrument breakage, something the rotary NiTi instruments are vulnerable to.

A further advantage of 30o oscillating stainless steel relieved reamers have over rotary NiTi is that the oscillating reamers don’t require the prior creation of a glide path. Indeed, these instruments produce a glide path via the engine-driven handpiece unlike the manual use of K-files used prior to the introduction of rotary NiTi. Common sense would inform rotary NiTi advocates that the creation of the glide path could be done far more rapidly and effectively employing the 30o oscillations of the relieved stainless steel reamer, but that would introduce the users to a technique that could then be practically applied for almost the complete instrumentation process. For marketing reasons, this is not done and most rotary NiTi users still go through the hand fatiguing and time consuming manual process of employing K-files.

When it comes to comparing the traditional use of K-files to stainless steel relieved reamers GPT-4 goes into detail why the relieved reamers are superior, factors that include their increased flexibility resulting from the reamer design having half the number of flutes compared to a comparably sized K-file that in turn required one half the number of twists to the original square or triangular wire making them appreciably less work-hardened and, therefore, more flexible. Being relieved along their working length as well as having half the number of flutes, they encounter less resistance as well as being more flexible making them more adaptable in negotiating all varieties of canal anatomy. GPT-4 also notes that the predominantly vertically oriented flutes along the length of the stainless steel relieved reamers are less likely to distort curved canals to the outer wall when the pull stroke is used to remove the instrument from the canal. The 30o oscillating handpiece confining the predominantly vertically fluted stainless steel reamers to short horizontal motions shave dentin away in a non-distorted fashion and when pulled from the canal, the vertical flutes are poorly designed to shave dentin from the outer wall of curved canals reducing the chances of distortion. In like manner, upon inserting the instruments into the canal, the predominantly vertical flute pattern is also poorly designed to impact or extrude debris apically unlike their K-file counterparts.

So, in summary, replacing both K-files and practically all rotary NiTi instruments, the alternative approach of employing 30o oscillating relieved stainless steel reamers for 98% of the canal preparation as noted by GPT-4 accomplishes the following:

. Prevents instrument separation

. Provides for three-dimensional debridement of oval canals and thin isthmuses

. Prevents distortions of curved canals

. Minimizes the chances of producing dentinal micro-cracks

. Less likely to to impact or apically extrude dentinal debris and bacteria

. Provides for multiple use of the instruments before replacement with great cost savings

. Adaptable for a far wider range of canal anatomy

. Eliminates hand fatigue while shortening procedural time requirements

. Effectively activates the irrigants driving them into intimate contact with the canal walls

. Minimizes personal procedural stress

Please note that in the final preparation of the canal, I use one helically relieved rotary NiTi instrument, but only after 98% of the canal preparation is done. I generally use a 30/04 that tends to encounter little resistance negotiating to the apex given that 98% of the canal preparation is already done with the 30o oscillating stainless steel relieved reamers where I typically prepare the canals to a minimum of a 35/02 or 40/02. The degree of preparation prior to implementing the single 30/04 (in most cases) minimizes the risk of the 30/04 helically relieved NiTi reamer breaking. It should also be noted that after the canal preparation is completed, I still go back with the 25/02 stainless steel relieved reamer for a final activated irrigation to remove the smear layer that develops when rotary NiTi is used. I now have a canal that at least mesio-distally has smooth walls that will show up well on x-ray and a space that again at least mesio-distally is sized for the appropriate gutta percha point.

All the advantages noted in this post are corroborated by GPT-4. What is most interesting is the confirmation by an unbiased algorithm of techniques that were developed long before AI existed. GPT-4 is confirming principles that if followed provide safe, more effective and efficient endodontic procedures. While rotary NiTi dominates today, all who use these systems know their downsides. What is not nearly as well-known is the alternative instrumentation system that compensates for those downsides. Because we developed the alternative approach, when I have posted the advantages of this alternative approach and critically review the shortcomings of rotary NiTi as well as K-files, I have been accused of bias for the sake of profit. Without getting into a never-ending debate with my one significant critic, let him refute the conclusions that GPT-4 has already generated as well as the many responses from GPT-4 I have yet to post. Bottom line: Nothing bad comes from an open-ended debate if it sticks to the issues at hand and personal assessments of one’s character are not germane to the discussion. In my estimation, focusing the discussion on mechanical principles is where the greatest insights are to be found and the least vulnerable to biased intentions.

Regards, Barry