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8 Dental Tribune Middle East & Africa Edition | January-February 2016 mCME Predictable Endo 102: Why warm and soft is so good System ‘S’ for injectable or carrier-based GP mCME articles in Dental Tribune have been approved by: HAAD as having educational content for 2 CME Credit Hours DHA awarded this program for 2 CPD Credit Points CAPPmea designates this activity for2continuingeducationcredits. > Page 9 By John J. Stropko, DDS T he author has been in pri- vate practice and a contin- uing student for the past 50 years. The first half was spent practicing restorative dentistry, and the second half in a specialty practice limited to endodontics. On the road to predictability, it became apparent there was a definite relationship present between root canal treatment, periodontal status, prosthet- ics and/or subsequent restora- tive procedures. Each operator has to decide what steps for a more predictable outcome they are willing to trust another to do. This article is an attempt to share some “secrets of success” and perhaps serve as a checklist for a system that works in the at- tempt to achieve predictability of endodontic treatments. During the earlier years of the past century, several techniques were devised for the obtura- tion of the canal system after removal of the diseased pulp, or necrotic tissue. Some of the most popular were silver points, lateral condensation of gutta- percha (GP), Sargenti paste and chloropercha. Currently there are seven techniques that utilize gutta-percha as the obturation material of choice: 1) Single cone 2) Lateral condensation 3) Chloropercha technique 4) Vertical compaction of warm GP (Schilder, continuous wave, System “B,” McSpadden, System “A”) 5) Carrier-based (Thermafil) 6) Injection of thermo-plasti- cized GP (often referred to as “squirting” using a Cala- mus or Obtura unit) 7) Mechanically assisted com- paction (Pac Mac). In 1967, Dr. Herb Schilder, often referred to as “the father of mod- ern endodontics,” introduced the concept of filling the root ca- nals in three dimensions.1 The Schilder Technique in- volved a new and different ap- proach for obturation of the ca- nal system and resulted in much controversy. Evidently, the controversy did create interest from some doc- tors, because in the mid 1970s new ideas and techniques evolved that became most of what are the currently accepted concepts of modern endodon- tic principles and techniques. Today, the numerous clinical reports, published research and the rapid advancements in technology have significantly changed the operator’s obtura- tion preferences. Ease of com- munication, along with modern marketing, has become a very important determinant when making a choice of techniques. More recent studies have dis- counted some previous obtura- tion materials that were popu- lar, but some form of GP still remains the most acceptable and widely used. The purpose of this article is to share a simple, six-step protocol (System “S”) in a straightforward manner, to achieve predictability of endo- dontic treatment for the benefit of the patient. There are six important compo- nents to the System “S” protocol: 1) Proper shaping with patency 2) Adequate cleaning, disinfec- tion and drying 3) Delivery of pre-warmed GP to apex (Calamus/Obtura) 4) Coronal seal for the rest of the system 5) Respect for the endo-pros re- lationship 6) Use of the surgical operating microscope (SOM) for the entire endodontic treatment The author believes that as long as the gutta-percha is in- troduced to the apical third of the canal system, pre-warmed and pre-softened, the deforma- tion and adaptation to the canal walls is more predictable, result- ing in a better seal that is signifi- cantly less “sealer-dependent.” It has been shown that the pre- warmed techniques (Obtura and Thermafil) produce a better seal than lateral condensation.2 Due to the lack of deformity in- herent at room temperature, the techniques utilizing non-sof- tened GP are more “sealer-de- pendent.” The two most popular thermoplastic obturation tech- niques are the “carrier-based” (e.g., Thermafil) and “direct in- jection” (e.g., Calamus/Obtura). The pros and cons of each will be discussed, but regardless of the technique used, the “shape” of the prepared canal system is of utmost importance and must be discussed. Access and shaping the canal system In the early ’70s, Schilder clear- ly stated the requirements for the proper shape using GP to achieve three-dimensional ob- turation of the canal system: 1) The root canal preparation should develop a continuously tapering cone shape. 2) It should have decreasing cross-sectional diameters at every point apically and increas- ing at each point as the access cavity is approached. 3) It should have multiple planes, which introduces the concept of “flow.” 4) The foramen should not be transported. 5) The apical opening should be kept as small as practical in all cases. There were several other re- quirements more clinically de- finitive. Following are a few of them: After placement of the rubber dam, an appropriate ac- cess is made. Unless the access is large enough for adequate vi- sion, appropriate instrumenta- tion may be compromised and canals missed. A perfect exam- ple is a maxillary first molar; if the access is made as though there was an MB2, it is amaz- ing how many times an MB2 is found. A general rule of thumb is, if you access for it, you are more likely to find it. A proper access will also facilitate the cre- ation of the continuously taper- ing shape of the canal, necessary for the warm GP technique. Occasionally after caries or old restorations are removed, a “pre-endodontic” restoration may be required to control and maintain a sterile environment until the endodontic treatment is complete. This can usually be accomplished using a bonded composite technique. Shaping should be confined to the anatomy of canal system, fol- lowing the natural curvatures. Instrumentation beyond the apex is unnecessary and may needlessly enlarge and deform the apical foramen.3 Using the Schilder protocol to achieve the desired shape of the canal system was a time-con- suming process. It involved the tedious use of pre-curved files and reamers to follow the ana- tomical curvatures of the canal. Other requirements that caused some controversy then (and still does), besides the size of the ac- cess opening, was the need to keep the apical foramen as small as possible, and to maintain pa- tency throughout the entire process. The majority of more recently published research and clinical studies have confirmed the rational for an appropriate access and correct shaping. In the early 1990s, technology brought about the introduction of rotary instruments, reliev- ing the operator of considerable time spent creating an accept- able shape. The ProFile rotary bur (Tulsa Dental) with 0.04 and 0.06 taper, was introduced to the profession. Creating the shape necessary for the success- ful use of the warm obturation techniques was made easier and faster. By the beginning of this cen- tury, numerous designs gradu- ally evolved utilizing varying tapers, active or passive cutting blades, etc. (Fig. 1). At first, the biggest problem with the rotary files was breakage during use. But modern nickel titanium (NiTi) metallurgy technology has developed more, and more dependable, rotary files. As a result, today the separation of a rotary instrument during use is of virtually little or no concern. Ithasalsobeenshownthatprop- er shape permits more thorough irrigation and the removal of significantly more debris from the prepared canal system. Disinfecting irrigation should be used between each instru- ment during the entire shaping process and patency continually maintained with a #10 file. Note: The quantity of irritants used is not as important as the frequen- cyofuse.Theirrigationprotocol, instruments, fluids, etc., are in constant evolution and becom- ing more effective. However, a clean and sterile environment of the canal system prior to obtura- tion is still the objective. Irrigation for cleaning the ca- nal system After shaping is completed, final cleaning can be effectively ac- complished by the alternative use of: 1) Warm 3- to 6-percent NaOCl 2) 17 percent aqueous EDTA for approximately 30 seconds (smear layer removal) 3) Warm 3- to 6-percent NaOCl (further disinfect and stop action of the EDTA). The NaOCl can be effectively warmed by placing the irrigat- ing syringes in a beaker of wa- ter set on a small coffee warmer (Fig. 2). The canal(s) are com- pletely flooded with the de- sired solution; an Endo Activa- tor (Dentsply) is appropriately used for the “tsunami effect,” then re-irrigated with the same solution for flushing of debris (Fig. 3). The NaOCl is then ef- fectively removed with a capil- lary tip (Ultradent) attached to a high-speed evacuator. Other Fig. 1. Typical rotaries, one of several popular brands. (Photos/ Provided by John J. Stropko, DDS, unless other- wise noted) Fig. 4a. The canal system can be very complicated. Fig. 4b. The Walter Hess studies with vulcanite clearly demonstrated the complexity of canal sys- tems. Fig. 5. Set of three Stropko Irrigators with various 27-gauge tips bent for use. Arrow points to the dedicated ‘air-only,’ sin- gle-button DCI syringe. Fig. 2. NaOCl irrigating syringes can be warmed in a beaker on a coffee warmer. Note the anesthetic syringes on a heating pad in the background. Fig. 3. The Endo Activator is used for the ‘tsunami effect’ for cleaning canals.