Oral Health Group

Practical Endodontic Suggestions for the General Dentist: Creating Ergonomics and Efficiency

February 1, 2007
by Richard Mounce, DDS

Being able to perform endodontic treatment as safely and efficiently as possible is a function of primary three components:

1. Choosing cases correctly for treatment or for referral.


It is difficult to give simple and arbitrary rationale for cases which might be referred, and when they can or should be done in-house. Empirically, 75% of my practice is either re-treatment of failed results or completion of those which have been started but not finished, and in which there is most often a clinical challenge which has been introduced into the treatment where it did not exist before (perforations, separated instruments, ledges, blockages, etc). If the general practitioner has the time, skills, equipment and will to perform the treatment to the highest level, it should be done at the time and place it was assessed, assuming consent was given. When these factors are not present, referral to a more skilled practitioner is necessary. What has value is an honest decision on the part of the clinician to assess, that in the given situation, if they are the best individual to treat that particular patient at that time. The clinician must also take into account any behavioral management challenges that exist. Rather than thinking that a treatment referred to another is a fee lost, one might see the possibility that a patient referred for the right reasons is likely a patient with whom trust will be built and a long relationship can ensue. This scenario is better than that of a patient who, after 1-2 troubled visits and an iatrogenic event, decides that the original clinician did not manage the situation correctly and then goes to seek out another dentist. It is an unfortunate situation, but happens often.

Assessing risks and case complexity is essential. In short, appreciating the challenge that will ensue (for example, root length, curvature, calcification, numbers of roots, amongst a host of different clinical challenges) can go far toward avoiding any iatrogenic issue. For example, the RNT file might separate or where the perforation is likely to occur before it happens can go far toward its avoidance.

2. Having one’s equipment properly organized to the greatest extent possible prior to treatment, so that it can be used effortlessly in clinical treatment. Knowing intimately what equipment one is using during treatment is a vital prerequisite for creating an excellent result.

Understanding technique and the equipment used to facilitate this treatment is a significant step toward making procedures flow smoothly and efficiently. Understanding, for example, what torque control is and how auto reverse torque control motors work is a significant issue with regard to making RNT files work to their greatest benefit.

First, organizing ones files in the order in which they will be used is highly beneficial. It bears recognition that hand files are used as pathfinders, scouting files and for negotiation of canals, as well as to create a glide path before the use of RNT instruments. As such, the clinician should have enough small K files available for use in such negotiation and glide path creation. For an average molar it might take 1 pack of #6 files, 1 pack of #8 files and 1 pack of #10 K files and several #15 K files to adequately negotiate and scout the canal space, and to create the glide path before the use of RNT files. A glide path represents a canal that has been enlarged to a #15 K file before the RNT file is engaged. While advocated methods for use of RNT files can vary, in my empirical opinion using RNT in a crown down manner in any given canal third, is the most effective method in the prevention of separation, blockage and iatrogenic events of all types. To create a crown down instrumentation, using RNT files from larger to smaller tapers and tip sizes can provide a safe and effective canal preparation that minimizes any possible iatrogenic event. Having the RNT files aligned on the sponge in the expected order of use, can allow the clinician to utilize them in the most effective manner possible.

I use the K3 RNT file system (SybronEndo, Orange, CA). These are arranged on the sponge in the expected order of use from larger tapers to smaller. K3 is a complete system and, as such, can be used in a variety of manners and pack configurations with varying taper, tip sizes or both. In addition, one can create their own pack configurations for their sponges by choosing from the assorted files that provide the most ideal usage based on the experience of the clinician. In any event, using the K3 system from larger tapers to smaller creates an inherently crown down preparation as each successively inserted file is advanced further apically than its predecessor.

Powering RNT files with electric motors creates the greatest efficiency in their performance. There are two systems on the market today that I consider to be state of the art for electric motor capability, in the effort to enhance the safety and efficiency of any given RNT system, not just K3. These are the Kavo ELECTROtorque TLC system (Kavo, Lake Zurich, IL) and the TCM III (SybronEndo, Orange, CA). The TCM III is a single corded motor with an electrical plug in. The motor is very dependable, has auto reverse and torque control and is cost effective. It is not rechargeable as it is corded to a wall socket. Hand held rechargeable models might not be ready if they are left uncharged. This will never happen with the TCM III. Also, model dependent, some handheld’s will not reach the same RPM as the TCM III which can reach 900 RPM with an 18:1 attachment.

As an aside, the author runs K3 at 900 RPM with the torque control off. The manufacturer recommends them to be used at 350 RPM. Such faster rotational speeds are possible if the engagement of the file against the canal wall is minimized to 1-2 mm per insertion. The touch is gentle, passive, and continuous and controlled. In addition, the K3 is always preceded by the creation of a glide path (the canal is taken to at least a #15 K file before RNT file use) aside from the other recommended use considerations. And finally, the K3 is never left rotating the canal at one place without being advanced apically or removed, especially while the file is around a curvature.

The ELECTROtorque TLC has additional features that go above and beyond simply providing an electric motor for endodontics. It is an electric motor system that is attached to the dental unit and has a hand piece that, with varying attachments, can provide an electric high speed, an electric low speed and the aforementioned electric motor for endodontics. The clinician can pre program multiple high and low speeds into the motor. The electric motor endodontic function can be pre-set for torque as well as the various speeds in multiple pre sets. The system has fiber optics and is very simple to use. Fewer cords, boxes and foot pedals are needed relative to many of the alternatives.

Knowing where to set the torque control on these various units is a matter of experience and personal preference. For a clinician new to RNT files using the lower torque control settings that will auto reverse easily is advisable. Many endodontists, myself included, turn the torque control off, so as to be entirely in charge of the files in the canal rather than rely upon any electric motor to auto reverse the files for them.

With regard to obturation, what equipment one will have varies considerably depending on whether the clinician is using cold lateral condensation, warm carrier based techniques or variations of the vertical compaction technique (including SystemB). The author uses SystemB with the down pack and back fill delivered via the Elements Obturation Unit (SybronEndo, Orange, CA, USA). The value of the EOU is that it can allow the clinician to provide a safe and effective flameless source of heat in one unit blended with an extruder, which can provide a heated stream of either gutta percha or bonded obturation in the form of RealSeal (SybronEndo, Orange, CA, USA).

The EOU is a stat
e of the art gateway/instrument for all of the warm techniques, except warm carrier-based models. This is because it can provide the heat needed to carry out thermal softening for gutta percha or RealSeal as well as a simple, economical and practical user-friendly means of backfilling canals.

3. Carrying out the treatment with the best ergonomic and efficient flow.

A relaxed and well-informed patient is a prerequisite for excellent treatment. Creating such a relaxed patient is a function of a well taken history, informed consent, profound anesthesia, use of the rubber dam at all times, copious irrigation (not simply for the function of creating cleaner canals, but the avoidance of debris blockages and recapitulation), excellent length control during treatment, and ideal cone fit amongst other similar considerations. Inherent in making any dental procedure flow well, but especially an endodontic one, is knowledge on the part of the clinician that ideally the procedure will be performed in a way such that each step is done correctly before moving on to the next. In essence, one well-performed step follows another.

Significant practice with extracted teeth is advised. Speed that is generated with expertise and familiarity with equipment can be achieved by repeated practice. It is obviously ill advised to take new equipment into the operatory and practice on live patients. Instrumenting canals and shaving back the dentin longitudinally and/or in cross section to observe the debris left, canal transportations, degree of complete obturation, etc can all provide important lessons for the clinician as to the effectiveness of the various procedures that they are now using, as well as how they might improve. If for example, the clinician can learn how much pressure it takes to fracture an RNT or transport a canal through practice, obviously the misadventure can be prevented in clinical practice.

Ergonomic flow within treatment can be produced by a well rehearsed procedure in which the clinician and assistant have rehearsed the procedure, and the assistant clearly understands the goals of treatment, the necessary instruments (as well as the order of their use without needing them to be placed in the proper order during the procedure).

Finally, two additional means for making procedures flow more smoothly and predictably are the employment of both digital radiography as well as a surgical microscope. I use DEXIS (DEXIS Digital radiography, Alpharetta, GA, USA) and Global Microscopes (Global Surgical, St. Louis, MO, USA). DEXIS allows multiple images to be taken in rapid succession, which has great value in allowing for a three dimensional mental imaging of the canal anatomy before treatment. This also allows the clinician to strategize before treatment, which can minimize the chances for iatrogenic outcomes. The surgical operating microscope allows the greatest possible visualization during root canal treatment bar none, given its commanding visualization and magnification during all stages of the process. There simply is no substitute for its capabilities.

In summary, choosing cases correctly in terms of knowing which should ideally be attempted and which should be referred; carrying out the treatment with the best ergonomic and efficient flow; and having ones equipment organized properly to the greatest extent possible prior to treatment can all provide the clinician an excellent opportunity to achieve a final result in the safest, most ergonomic fashion. Knowing intimately what equipment one is using during treatment is a vital prerequisite for creating an excellent result.

I welcome your questions and feedback.

Dr. Mounce has no commercial interests in any of the products mentioned in this column.

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