Written by Richard Mounce, DDS Sunday, 31 December 2006 19:00
How does any endeavor move from OK to good, from exceptional to elegant, and then ultimately to the level of an art form? How can one achieve this transcendence from a white line on a radiograph to a work of art in an endodontic context?
Several simple factors can make a completed task rise from “just good enough” to “exceptional.” One is a mastery of basic skills blended with a vision to see what needs doing before it becomes obvious to the untrained eye; another is having an intense passion to create the best possible result with the given instruments at hand. Transcendence to the art form requires one to stay the course until it is not only done correctly but until the myriad of small details involved in making it unequalled in quality are mastered.
This has direct application to providing exceptional endodontic therapy. The process can be viewed in many ways. For example, it can be viewed as simply grinding out a canal and trying to “fill” it (think drinking red wine from a cardboard box). By contrast, it can be viewed as 3-dimensional dentin sculpting in an infinitely complex space so as to obturate the prepared space with a thermosoftened replication of the internal anatomy (think an excellent, handcrafted, aged, oak-laden cabernet).
What elements are essential to create the difference between these two outcomes? In essence, what raises endodontics to an art form, and what is simply a “root canal?” If the patient was our mother or loved one, which level of service and awareness would we choose? Which result would likely be better? There are an infinite number of steps to create transcendent results, but they can be assigned to one of several basic concepts:
Figures 1 and 2. Clinical cases performed with the techniques discussed using K3 rotary Ni-Ti instruments and RealSeal bonded obturation (both SybronEndo).
1. The clinician appreciates the infinitely complex nature of the anatomy of the root canal system, and rather than be intimidated by the fins, culdesacs, lateral canals, fourth canals, trifidities, delta canals, and bifidities, these clinicians seek to negotiate and explore this most delicate space with the care and respect required. In practical terms, this means that patency files will be used extensively at all times in the process. The small hand K-files (6s to 10s) will be prebent and inserted gently coincident to copious irrigation at all stages in the process. These hand files will precede rotary Ni-Ti (RNT) files in the vast majority of clinical cases and given canal levels being instrumented irrespective of the RNT brand.
To place a RNT file into a canal that has not been carefully explored with hand files first is to encourage iatrogenic outcomes, not the least of which are separation, canal transportation, blockage of the canal with debris, ledging, and transportation of the apical foramen. The single thing that sets the master apart from the novice in endodontics is a cognition and tactile dominance over the canal with regard to keeping the canal path clear via patency files, and not allowing chips of debris to block the canal path during the accidental and undesirable propulsion of pulp and canal debris apically during the emerging canal preparation. Both create a nidus of debris that can provide apical bacteria, which if left in enough quantity and virulence are the harbinger of a failed root canal.
2. Canals are shaped to address the anatomy at hand (not some arbitrary approximation based on anatomical averages). Regardless of the original anatomy of the canal, the final canal shape has characteristics that are inviolate but whose creation takes into account the anatomy that is being shaped. Specifically, the clinician seeks to enlarge the canal in 3 dimensions. In doing so he or she leaves the canal in its original position and the minor constriction at its original size and position (not altering the anatomy of the apical foramen), and creates narrowing cross-sectional diameters from the minor constriction to the orifice. Making this occur reproducibly during the cleaning and shaping of root canal systems requires patience, only one step of which is that listed in step 1 above.
Such patience can be demonstrated, for example, in how orifice openers are used. Rushing in quickly and forcefully can lead to undesirable outcomes very quickly. Knowing when to use orifice openers, for example in coronal third enlargement, and when to spend significant time by hand to get the canal to a size where it might be ready to accept an orifice opener, takes clinical judgement. For example, if the orifice of a canal is small and calcified, placing an orifice opener too quickly into such a canal can very easily block the canal with chips of dentin debris. Aside from just knowing whether to use an orifice opener, it has value to know the correct size of the orifice opener to use so as to prevent unnecessary removal of dentin cervically and potential weakening of the root, predisposing fracture. Seeing the potential problem before it occurs by being fully focused on the clinical entity that is present can go far toward avoiding the problem and creating the needed access to the apical foramen to allow its subsequent management.
While it is not possible in one paper to discuss all the various nuances of shaping technique, suffice it to say that bearing in mind the key principles of canal shaping outlined above in a focused and patient manner can go far toward avoiding iatrogenic problems and creating the art form. Future articles will address specific instruments and sequences for canal instrumentation; although canals can be shaped beautifully with many different file systems and sequences, how the files are used transcends specific design characteristics.
RNT use is gentle, passive, from the fingertips, slow, deliberate, and done with intention but not forced. A file is never pushed apically if it does not willingly want to go. And finally, a glide path ideally must be created before a RNT file is placed to the same length in the given third of the canal. Once a RNT file is inserted, astute clinicians instinctively irrigate and recapitulate (re-ensure the canal patency) so as to make sure that debris is not present in the canal that might be carried by the next file insertion and block the foramen and/or be extruded apically.
3. Respect for the apical foramen is paramount at all times. Couples may have disagreements, but those in a fully committed and successful longstanding relationship make it a habit never to lose respect for their spouses. This analogy applies to the apical foramen. If the position and size of the minor constriction are transported and violated, results become less predictable and far more problematic to achieve. Two common violations of the apical foramen are mechanical transportation and its blockage by debris. Both of these outcomes are virtually always avoidable and not due to calcification or difficulty of the given tooth. Debris should never accumulate or block the patency of the apical foramen. The apical foramen, if maintained at its original position and size, can act as a natural stopping point for instrumentation, irrigation, and obturation, and if respected, make these 3 tasks far more predictable and effortless. The converse is true. “Respect” in the context here implies that the clinician will know to what depth all files and irrigants are being placed into the canal at all times. Files, especially RNT, are not blindly placed down canals, especially into the apical third, unless the clinician knows to a high degree of certainty where the minor constriction lies and ideally what the diameter of the minor constriction is.
While a comprehensive discussion of the size of the minor constriction and its impact on apical preparation size is beyond the scope of this paper, it bears mention that it is absolutely essential to know the diameter of the minor constriction so as to appreciate to what diameter to finish the apical preparation. Obtaining the diameter of the minor constriction is done by a process called “gauging” the apex. Gauging is accomplished with a .02-tapered hand K-file. The hand K-file that binds at the minor constriction of the apical foramen is the diameter of the minor constriction of the apical foramen. Knowing the initial diameter of the minor constriction allows the clinician to match the final prepared diameter to the actual anatomy of the canal space. A future article will discuss how to interpret this initial apical diameter in relation to choosing the final prepared canal diameter.
Using hand K-files to ensure that the minor constriction is open and patent at all times is a key core value for clinicians who appreciate the delicate nature of the apical third. RNT files can inappropriately be used aggressively; as in many canals they can easily slip into the apical third. If the use of such files is not carefully monitored mentally for depth and the position of the file in relation to the minor constriction, then file breakage, blockage, and canal transportation can ensue. For example, if the RNT file should begin to track a previously unexplored fin or cul-de-sac, it can easily become bound at its tip. Alternatively, if a RNT should encounter remaining debris, such debris can be compacted further apically or cause the file to wind upon itself and fracture. Both of these potential outcomes are avoidable with a diligent attention to detail with hand files, which can help act to remove debris by recapitulation combined with irrigation. For vital pulps, especially on younger patients, and for necrotic cases with significant pulp tissue volume, a viscous EDTA gel or material like KY jelly is advised to hold the pulp in suspension until it can be flushed out of the canal.
4. World-class clinicians rehearse the procedure mentally before it is performed; potential problems are dealt with while they are potential and not actual. World-class clinicians practice constantly. Their attitude is one of the Japanese business concept of “kaizen,” ie, a slow and continuous improvement. The clinicians are always learning, always curious about new ideas, materials, and techniques. They are open-minded. These clinicians believe that tomorrow’s ideas and technologies will be better than today’s, and that their own knowledge, clinical skills, and mindset can be expanded. The experience is approached with a beginner’s mind. Such a mind is open to all possibilities instead of imprinting its own values and often-arbitrary opinions onto the given clinical situation. For them, endodontic therapy is not one-size-fits-all. Their treatment is handcrafted; it is anything but cheap. Using a sporting metaphor, everything the clinician has is “left out on the field,” and nothing is left behind. The clinician’s mind is fully focused at all times on the procedure, also known as being “in the zone.” In a practical sense, one manifestation of this is that the clinician mentally interprets all the tactile sensation in his or her fingertips and assimilates that to his or her visual input, ideally through a surgical operating microscope. This allows the clinician to be mentally in 2 places at one time…the place he or she is at that moment, but also where he or she needs to be in the next 5 seconds. If the 5 seconds between the 2 moments are held together and remain primary in the clinician’s mind, then these 5-second bridges, cognitions, and awareness link together into minutes of a focused procedure, one that is accomplished and finished with real style and substance, ie, one that was done matching the clinical requirements of the tooth at hand with the treatment rendered. Such an approach allows a custom and handcrafted treatment result, not one that was derived from a menu-driven cookbook, where arbitrary and irrelevant values are imprinted onto the tooth.
An appreciation of the vital importance of respecting the apical foramen (and maintaining its patency, especially with the use of hand files) in light of canal shaping principles blended with the mental discipline and focus needed can go far to achieve transcendence in an endodontic context, from merely “finished” to “finished with real quintessence” for the patient, ie, transcendence (Figures 1 and 2). These concepts will be expanded upon in future articles. I welcome your questions and feedback.
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