Richard Mounce, DDS
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Given the huge variety of choices in the endodontic marketplace, especially when you want to make a change, it can be difficult to know which materials and methods to adopt. The initial decisions about materials and methods made by young clinicians are often based on what the senior doctor recommended, what was taught in dental school, or what the doctor down the hall recommended.
Some systems do some things very well, but few systems are ideal for all clinical situations. While opinions vary and excellent endodontics can be performed with a variety of systems, here are my recommendations and rationale for instrumentation and obturation systems.
Relative to Gates Glidden drills and hand files, rotary nickel titanium (RNT) instrumentation is highly recommended. To use GG drills and hand files in 2009 is to ignore, when used correctly, a highly predictable technology.
Of the RNT file technologies available, I confidently use the Twisted File (TF)*. This file is available in multiple tapers .12 to .04 with a basic tip size of No. 25, as well as .06/30, .06/35, .04/40, and .04/50. Also, .06/30, .06/35, .04/40, and .04/50 are ideal for preparing enhanced apical sizes.
To create a “basic preparation“ to a tip size of No. 25, TF is used crown down from large tapers to small, after the glide path has been made. After the basic preparation (a .08/25 or .06/25 has been taken to length), enhanced apical preparations are made using a step back method.
Said differently — said clinically — the .08/25 or .06/25 basic preparation is followed by a .06/30, .06/35, .04/40, or .04/50. The clinician decides which of these apical sizes will be prepared, ideally based on the initial diameter of the minor constriction of the apical foramen.
TF is extremely flexible, cuts exceptionally well, and allows larger tapers to be created than are possible with RNT. These are manufactured by grinding, and by doing so with fewer insertions than other file types. Orifice openers, such as GG drills, are not necessary with TF.
Endodontists generally favor warm obturation systems over cold methods. Cold lateral condensation requires sealer to fill in the spaces within the canal between the master cone and accessory cones.
In a single cone obturation, the clinician depends on the movement of sealer into all the ramifications of the pulp space during the insertion of the single cone. The hydraulic movement of sealer into all of the ramifications of the prepared canal is not predictable anywhere near the degree it would be with the vertical compaction technique, SystemB, or the warm carrier-based technique.
Despite being heralded by some as a “gold standard,“ gutta percha has limits. It is dependent on a coronal seal to provide predictable clinical success. It does not bond to dentin or sealer. There is evidence in the endodontic literature that gutta percha degrades in root canals in a time dependent fashion.
RealSeal bonded obturation overcomes many of these limitations and can be applied in either master cone form or by an obturator (RealSeal One Bonded Obturators)*. RealSeal has been shown, in vivo and in vitro, to reduce microleakage across the totality of the canal when compared to gutta percha in clinically relevant side-by-side studies.
To use RealSeal, the smear layer must be removed with a liquid EDTA solution such as SmearClear.* After flushing with distilled water, the canal is ready to obturate with either master cones or RealSeal One Bonded Obturators. I have used RealSeal exclusively since January 2004. I would never go back to gutta percha due to its shortcomings.
Virtually every crown I have ever accessed in re-treatment has shown overt evidence of coronal microleakage. Leakage is clinically manifest by cotton pellets left from the previous obturation, unset restoratives, caries, voids, discolored gutta percha, purulent drainage, odor, and other signs.
Using RealSeal and placing the coronal build-up at the time of obturation under the rubber dam are significant steps that when taken together can predictably eliminate posttreatment coronal leakage and improve long-term outcomes.
Finally, whatever materials and techniques are used, practice on extracted teeth and a comprehensive clinical and literature-based understanding of their use is required to competently treat clinical cases. Hands-on courses, lectures, and Web-based CE and the endodontic literature all have excellent information and provide training resources. I welcome your feedback.
* SybronEndo, Orange, Calif.
Dr. Mounce offers intensive, customized, endodontic single-day training programs in his office for groups of one to two doctors. For information, contact Dennis at (360) 891-9111 or write [email protected]. Dr. Mounce lectures globally and is widely published. He is in private practice in endodontics in Vancouver, Wash.
