Reciprocation Innovation

Doug Kase, D.D.S.

Tales from the Chamber:
Reciprocation Innovation

Doug Kase

ERTAIN INNOVATIONS or techniques in a dentist’s life make a dramatic difference in the way he or she practices. For some it’s a new procedure or technique; for others it’s a new instrument or product. As an endodontist I have been subject to a barrage of all of the above over the years. New techniques and philosophies, such as crown-down instrumentation; new instruments, such as nickel-titanium in various tapers; a slew of constantly changing rotary techniques and a slew of different handpieces; and of course the many different methods of obturation techniques are only a few that have had their impact on the practice of endodontics. For my father, who graduated in 1943, moving from stand-up to sit-down dentistry made a big difference. For me, leaving the stomach-churning world of rotary Ni-Ti for the safer pastures of a more reliable, predictable, and safer system of doing root canal was the ticket!
    I am sure you all remember our Simplified Endo Technique (S.E.T.), which used .02 tapered standard stainless steel reamers in combination with .04 and .08 tapered NiTi hand instruments to create a greater tapered canal. This was the beginning of a stress-free endodontic evolution in my professional life. When our technique further evolved with the advent of SafeSiders and a further refinement of the system, so came another level of stress reduction and predictability. Using this technique in combination with electronic apex location has allowed me to do one-visit endodontics in a safe and stress-free way with incredibly predictable results.
    Well, something else has come along! For weeks, Barry Musikant has been asking me whether I have tried adding a reciprocating handpiece to my armamentarium for doing our EZ-Fill SafeSiders technique. Being the stubborn person that I am, I asked myself why I should add a handpiece when the system is so easy the way it is? I was already doing one-visit molars in under an hour with little stress, so I wondered how this handpiece could improve my technique. Well, readers, I gave it a try and needless to say since that day I have used my reciprocating handpiece for all instrumentation over a # 20, including NiTi, in the EZ-Fill SafeSiders technique.
    The advantages of using a reciprocating handpiece are many besides the obvious one of decreased hand fatigue for the operator. I have been using the NSK reciprocating contra-angle on a Star slow speed engine. Its 30-degree reciprocation from center in clockwise and counterclockwise directions provides stress-free instrumentation of the canal without the instrument’s reaching a resistance point. We all know that we try to replicate this movement with our hands; however, the proprioceptive feeling that we get prevents us from moving past this subjective resistance point. Since this can be a subjective boundary, it differs for different operators. Moving beyond this point can distort an instrument or—even worse—eventually cause an instrument to fatigue and fracture. Since the movement of the instrument in the handpiece never meets and moves beyond this point, the risk of fracture becomes incredibly low with stainless steel instruments and, even more importantly, with NiTi instruments. Coupling this low risk of fracture with a pre-bend test for NiTi instruments makes the likelihood of a separation within the canal almost non-existent. When the reciprocating handpiece is used in a pecking motion, its rapid reciprocation works synergistically with SafeSiders reamers to provide a more rapid and efficient instrumentation. Remember that the flat on the SafeSiders reamer not only helps with negotiation to the apex, but also acts as a chisel that allows the instrument to cut in both directions. I have tried using the NSK in both straight and curved canals, and it really works!
    A note to my “Rotary” colleagues: if you love rotary endodontics because you need a handpiece to reduce hand fatigue during instrumentation, then this is the innovation for you. Using a reciprocating handpiece with the EZ-Fill technique will fulfill all your requirements for performing stress-free endodontics.
    The following case is an example of the results that can be achieved using this technique in a curved canal with the addition of the NSK handpiece. (See Figures 1 and 2.) The results are the same, but the effort and operator stress required to achieve the results are greatly reduced.


FIGURE 1: The canals were instrumented by hand to a # 20 and then the # 2 Peeso reamer was used to straighten the coronal architecture of the canal as much as possible before the NSK reciprocating handpiece was used for the rest of the SafeSiders instrumentation.	FIGURE 2: The final film shows the same predictable results that we have all become accustomed to when using this technique.

FIGURES 3 AND 4: Different cases, same technique, same results!

Fall 2004

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