Written by Richard E. Mounce, DDS Monday, 01 March 2004 00:00
One of my favorite uncles used to describe how winning motocross races relied on the skill of the rider and not the motorcycle. A talented racer on a less powerful bike could predictably beat a less skilled competitor on a superior motorcycle. Summing up such a description, my uncle would almost always conclude, “It’s the rider, not the bike.” The dental equivalent might be stated “It’s not the material, it’s the operator.” A skilled dentist can perform excellent endodontic therapy with a minimal armamentarium, whereas with even the most advanced technology, the novice may struggle.
What are the critical skills and factors that allow the astute clinician to create excellent endodontics for his or her patients? What follows are 7 tangible factors that help shape the difference between excellent and less-than-desirable results.
FACTOR 1: START WITH THE END IN MIND
Preoperatively, visualize how the final case ideally should appear. Evaluating all the various clinical challenges that can reasonably be foreseen and developing a management plan for these obstacles can go a very long way in preventing needless complications of often nonexistent problems (as Dr. Cliff Ruddle of Santa Barbara, Calif, likes to say). Strategies for assessing case complexity (number, length, and curvature of roots; calcification; location of the tooth; patient cooperation; limitation of opening; etc) are beyond the scope of this paper. Obviously, however, the more risk factors that can be identified and solutions mentally rehearsed preoperatively, the better.
That said, even with the best preparation, there always will be additional issues that may arise midtreatment. For example, recognizing that an upper bicuspid has 3 roots radiographically is not enough. Mentally, the next step involves being aware that locating and negotiating each of the 2 buccal canals often can be quite challenging, especially when the coronal third makes an acute bend away from the canal orifice (as it frequently does). As a result, it may be necessary to accentuate the access toward the given line angle of the tooth to provide the best straight line access for the canal.
In addition, as one moves through dealing with each of the various clinical challenges present in a given tooth, it is essential not to move to step C or D in the performance of the endodontic therapy when step A and B have not be completed properly first. In other words, do not skip steps that successively build upon one another. For example, as above, if one doesn’t have straight line access into the canals, it is counterproductive to begin to shape the root canal system. Each step must be done properly and with intentionality to build a small series of excellent miniature procedures upon one another so that the final result is the desired endodontic outcome (diagnosis, access, coronal third shaping, irrigation, etc, following one another in the correct order). In essence, the initial mental visualization of the final result slowly is formed into reality (Figures 1a and 1b).
|Figures 1a and 1b. Preoperative evaluation of this clinical case centered on visualizing the intended result in managing the removal of the separated file in the MB canal of the upper molar. Each step in its removal and subsequent re-treatment was rehearsed mentally prior to beginning the tooth.|
FACTOR 2: OBTAIN AN ACCURATE AND TIMELY DIAGNOSIS
Almost daily, I meet patients who have had obvious pulpal pathology for many days to weeks for a host of reasons, and treatment has been delayed by the referring doctor in the hope that the sensitivity will go away, even in the presence of clear indications for root canal therapy. Simply put, if the patient has nocturnal or spontaneous pain localized to a tooth, lingering pain to hot or cold, pain to hot relieved by cold, pain to biting accompanied by the symptoms listed here, and pain that is getting worse especially after recent restorative treatment, root canal therapy is generally required. Trying to shield the patient from the “bad news” that they need a root canal and hoping that the problem will go away often ends up in frustration for all parties.
How often has each of us found a radiographically visible periapical abscess in a recently crowned symptomatic tooth that was not pulp tested or x-rayed prior to placement of the permanent restoration? More often than we would like. Prior to restorative treatment, carefully evaluating the tooth with both recent bite wing and periapical radiographs as well as pulp testing with hot, cold, and possibly electrical means is advised. If the tooth does not test comparably to the other teeth used for comparison (at a minimum the contralateral tooth and optimally the whole quadrant in question), and there has been a previous pulp cap, deep filling, many coronal fractures, etc, serious consideration should be given to performing the root canal treatment prior to extensive restorative treatment. Hopefully, this would prevent a later flare-up and access having to be performed through the new crown or bridge.
FACTOR 3: TAKE ENOUGH RADIOGRAPHS TO BUILD A 3-DIMENSIONAL MENTAL IMAGE OF THE TOOTH PREOPERATIVELY
At least 3 preoperative films (mesial, distal, and straight on) and 2 to 3 postoperative films are often needed to appreciate fully all the minute anatomical details present in many teeth. A single film examined casually from across the room will most often miss subtle yet important visual clues. Performing excellent endodontics without appreciating these details is a challenge. For example, a third root on a lower molar, the uncommon fourth root on an upper molar, or third root on an upper bicuspid, can be easily missed without taking all the needed off-angle radiographs. Normal anatomy and a myriad of factors can influence the interpretation of a single radiograph, but with multiple views it generally becomes relatively simple to interpret the true 3-dimensional (3-D) picture. A periapical radiograph is a 2-dimensional representation of a 3-D object, and taking these 3 views allows the creation of an actual road map to the canal’s multiplanar curvatures, number of canals, the presence of coronal microleakage, lateral root and periapical lesions, etc (Figures 2a, 2b and 2c).
|Figures 2a and 2b. Numerous off-angled radiographs provide a very different view of the true clinical picture with regard to the distal root of this lower molar.|
|Figure 2c. Off-angled view of the tooth reveals 3 distal canals.|
FACTOR 4: EXCELLENT ANESTHESIA IS A MUST
How often do we have difficulty anesthetizing a patient, or have a patient who is numb but loses anesthesia before we are finished with the procedure? How often in the above scenario are we “in no man’s land” where the patient wants to finish the procedure but is not profoundly numb, and the root canal becomes a rodeo? I have combated this by taking approximately 20 minutes for lower molar anesthesia via inferior alveolar blocks to take effect prior to treatment (ie, my series of inferior alveolar blocks or other anesthesia is given over a 20-minute period).
For an example of my clinical technique, let’s assume the most difficult possible combination of clinical circumstances, which could be a phobic patient in considerable pain from a “hot” lower molar (irreversible pulpitis) that has a long history of not obtaining profound anesthesia. In the absence of a medical contraindication, I generally first give Carbocaine (Cook Waite) without a vasoconstrictor (so as not to initiate or potentiate an anxiety attack by their endogenous epinephrine, already at high levels, being fueled by the additional adrenaline in an initial anesthetic injection). This is followed by 2 cartridges of Articaine (trade named Septocaine/Septodont) via inferior alveolar block (assuming no medical contraindication) over the aforementioned 20-minute period (usually about 10 minutes apart). In other words, Carbocaine without a vasoconstrictor is given first at minute 1, followed by 2 single cartridges of Articaine at minutes 10 and 20, respectively. Occasionally, it may not be necessary to give the second cartridge of Articaine.
Prior to beginning access, I virtually always test the tooth to cold and percussion in addition to examining for lip signs of anesthesia and having the patient tell me they feel as numb as they would expect. It is very rare for me to need intraosseous anesthesia or an intraligamentary injection for supplemental anesthesia with the technique described above. Articaine has been a revelation for me. Equivalent amounts of Articaine vs. 2% Lidocaine 1/100,000 epinephrine have given me dramatically higher effectiveness for inferior alveolar blocks. I highly recommend it if used appropriately.
FACTOR 5: OBTAIN THE ACCURATE AND “TRUE” WORKING LENGTH
Working length is determined by 4 common methods: radiograph, electronic apex location, bleeding point, and tactile sense. None of these methods is completely reliable in every clinical situation independent of the others.
Radiographs can be deceptive. Apex locators have traditionally needed some interpretation in that the operator must know when the machine is “lying” or giving an inaccurate length. A new 4th generation machine, the Elements Diagnostic Unit (SybronEndo), with performance based on new mathematical calculations, has gone a long way toward eliminating this historic weakness. A discussion of the Elements Unit is beyond the scope of this paper, but the reader is encouraged to evaluate it against his or her present apex locator. Tactile sense alone used for true working length determination is fraught with peril. Hoping to reliably “pop” through the apical foramen is certainly possible but subject to interpretation, as well as being difficult to reproduce predictably. In addition, this method is not universally applicable to all clinical cases, even in the most gifted hands.
Mentally imaging the length of the tooth (along with the anticipated master apical file size) preoperatively and confirming the length with at least 2 or more of these 4 methods has significant value. Instrumenting short to an inaccurate working length can unnecessarily predispose the tooth to the creation of numerous iatrogenic events, including ledging, perforation, zipping and tearing the foramen, etc. Other than scouting files to first explore the apical third, it is highly recommended that true working length be determined accurately before significant apical instrumentation to avoid the aforementioned problems (Figures 3a and 3b).
|Figures 3a and 3b. The anticipated working length of this tooth was 21 mm, which was very close to the exact length in all canals. Estimating the length of tooth provisionally before beginning treatment has value in avoiding iatrogenic events.|
Using a bleeding or moisture spot on the tip of a paper point as a method to obtain true working length can be accurate and reliable if done correctly. An article by Dr. David Rosenberg in Dentistry Today, March 2003, describes the technique. If a bleeding or moisture point can’t be reliably obtained, it is likely that the canal is under instrumented, ledged, blocked with dentin mud, or for other reasons patency has been lost.
FACTOR 6: ATTAIN “DEEP BODY” SHAPE
In general, shaping the coronal and middle two thirds of root canal systems is straightforward. The apical third is problematic and represents the challenge. “Deep body shape” refers to the ideal shape that should exist at the junction of the middle and the apical third of the canal. This space might be considered the “gate keeper” to the apical third. If this space is not properly managed, what happens beyond is done without control and most often with less-than-satisfactory results. How often have we seen gutta-percha that “wimps out,” where the filling seems to become increasingly narrow or nonexistent in the apical third? Amongst other causes, lack of deep body shape is most often the cause. Without deep body shape, it is virtually impossible to irrigate the apical third properly, resulting in accumulated debris that can act as a source of failure or iatrogenic misadventure.
These aforementioned problems arise from a large number of often small breakdowns that have occurred prior to negotiating the apical third. Such “breakdowns” might include:
(1) lost patency;
(2) inadequate anesthesia;
(3) a lack of crown down instrumentation technique;
(4) inadequate irrigation;
(5) inadequate experience with or a lack of confidence in one’s rotary nickel titanium file system to use the files to the true working length for fear of fracture;
(6) difficult anatomic challenges (long, narrow roots; severe curvatures, etc) that are beyond the operator’s comfort zone; and
(7) the operator giving up in the interest of time or convenience and finishing the tooth at the present level (probably the biggest single factor preventing the creation of excellence!).
Referring to No. 5 above, confidence in the resistance of a given rotary nickel titanium file system to fracture can strongly influence how it is used. Recently, I had an endodontist tell me that he “holds his breath” with his system. I don’t hold my breath with mine. I use the K3 rotary nickel titanium system (SybronEndo). Detailing the use of these files is beyond the scope of this paper, but suffice it to say that varying either the tip sequence from larger to smaller (they are available in 15 to 60 tip sizes in 0.04 and 0.06 tapers) in the same taper, or varying the taper with progressively smaller tip-sized instruments (0.06 tapered instruments followed by 0.04) can allow the operator to achieve deep body shape confidently with little fear of instrument fracture and use these rotary instruments to their full potential (Figures 4a and 4b).
|Figures 4a and 4b. Case treated with the K3 rotary nickel titanium file system (SybronEndo).|
FACTOR 7: GIVE YOURSELF ENOUGH TIME TO PERFORM EXCELLENT TREATMENT
How many times have each of us looked at an excellent result in some aspect of dentistry and said to ourselves “I could do that if I only had the time?” If we have asked this question, then why don’t we simply allocate enough time? In response to this challenge, each of us might ask ourselves, what are we doing to close the gap between where we are now in our skills and knowledge and where we know we have the capability of going? The difference in the 2 attitudes is not academic. Do we take the advice of “experts” and sales reps at face value without testing the materials, technologies, and methods first on our own, or do we cross-check “facts” with all the available literature?
We might ask, “Have I taken a wide range of courses on the same subject within the field to get a diverse range of opinion and heard conflicting information?” As an endodontic presenter, I often hear dramatically conflicting claims made pro or con with regard to different techniques and materials. The only rational response to these contradictions is to balance a literature search for evidence tempered with personal experience and that of our colleagues. A byproduct of this learning will be greater competency, and with it increased speed and efficiency.
To allow ample time, having an adequate fee structure and providing our therapy efficiently is essential. Profitability (through an adequate yet equitable fee) creates the time needed to perform excellent endodontics and provides a platform on which to operate at the highest level possible. Enhancing efficiencies can certainly shorten treatment times (in essence create more time) and increase profitability for some cases (not all). Techniques to enhancing efficiencies might include:
Learning to master the surgical operating microscope (which will provide more longitudinally successful treatment because of fewer missed canals, fewer iatrogenic events, etc).
Mastering rotary nickel titanium instruments, which are more efficient in canal shaping relative to their stainless steel hand counterparts.
Creating an unconditional mental focus on the tooth during the actual procedure. Treating one patient at a time, removing background noise and commotion in and around the operatory, and treating patients in 1 visit if indicated are all simple techniques for achieving and maintaining focus.
Mentally visualizing where one is at all levels of the procedure and what step is needed in the next 5 seconds and 5 minutes (where the procedure is going and why) is a powerful means actually to deliver the procedure to its intended destination. In contrast, “cookbook” endodontic techniques as recommended by some manufacturers might work well until the operator runs into a tooth that has not read the book prior to its treatment, much to the dismay of the tooth, the patient, and the unsettled operator. Much like airplane pilots are prepared for all kinds of hazards and midflight problems, we also must be ready to address a host of issues that can occur midtreatment in order to prevent our treatment from crashing. Knowing when one is “in trouble” and when referral is indicated is critical for maintaining the best possible long-term prognosis for the tooth and giving the patient the chance to experience excellence (Figure 5).
|Figure 5. This lower molar would defy all attempts to be treated by a “cookbook” endodontic technique; it might challenge even the most gifted dentist and would require every effort possible at preoperative visualization and in-treatment focus.|
Having one’s instruments laid out in the order they will be used, as well as performing “dry runs” of the procedure with staff on a periodic basis can improve efficiencies and gain needed time. The worst of all endodontic worlds is the scenario where a staff member is digging through plastic containers chairside trying to scrape together needed files and materials that are unfamiliar to the assistant and doctor. Patients know if the treatment being performed is familiar and has been choreographed and rehearsed properly.
If you are using a new rotary nickel titanium file system, I would strongly suggest practicing in extracted teeth repeatedly until using the files becomes second nature. For example, in such practice, if one intentionally separates rotary files, a new skill will be learned about the dynamic movement of placing the file into a curved canal in tandem with the selected torque and RPM of the electric motor and how much force it takes to separate the file. Such practice might be analogous to a pilot practicing in a simulator in various challenging scenarios. Eventually the operator will gain experience, which will make the real treatment at chairside (where it matters) much smoother for all involved.
Achieving excellence in endodontics is ultimately a matter of creating the time needed to let our talents come forth, unconditionally focusing on the clinical case at hand, and familiarizing ourselves with and mastering the vast array of techniques, materials, and equipment that allow excellent endodontics to flourish.
A skilled motocross racer who uses every bit of his experience can win the race even when not riding the highest performance bike. We as dentists can take advantage of both an amazing array of new equipment and technology (like being on the best performance motorcycle available) and blend it with an undiminished attention to detail and clinical experience to provide that extra edge to finish the race at or near the top.
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