With the wealth of options available in obturation, it can be a challenge to know which technique to adopt and what the ramifications of these choices are in clinical practice. As a first step, obturation techniques might be divided into their general classes. There are master cone based techniques (warm and cold), paste techniques, “squirt” methods and carrier based products. Described briefly:
1. Master cone based techniques would include cold lateral condensation, SystemB, the vertical compaction technique, single cone methods, Pac Mac, System A and lateral condensation followed by warm compaction.
Cold lateral condensation is the time-honored method of obturation that, while simple in application and concept, relies heavily on sealer to take up the spaces within the canal where the core obturation material never reaches. In practical reality, the apical half of many cold lateral condensation cases is single cone obturation as the spreader used for this method does not often reach the apical half of the root. Core obturation material is not moved by intention into the narrowing cross sectional anatomy of the prepared canal and does not fill all of the ramifications of the cleared canal space because the points are adapted together cold.
SystemB relies on a source of heat and extrusion of a heated obturation material. I have bonded all my obturation with RealSeal since January 2004 with the Elements Obturation Unit (EOU) (SybronEndo, Orange, CA, USA) (Fig. 1). The SystemB technique is simple in concept and validated in the literature. Under a surgical operating microscope (SOM, Global Surgical, St. Louis, MO, USA) it is possible to perform the downpack and backpack with precision. The SOM in all methods of obturation can allow an intentional placement of sealer with the Skini syringe and Navi Tip, 29 ga., 17mm (Ultradent, South Jordan, UT, USA) (Figs. 2 & 3).
While purists might argue differently, vertical compaction is a variation of SystemB with vertical compaction being the precursor of the two techniques. The techniques are very similar in that both rely on heat to soften the master cone and use cold compression to move the heat softened mass of material into the canals. In SystemB this cone is compacted in one downpack motion (one wave of condensation), in vertical compaction there are multiple downpacks, alternating heat and pressure.
Pac Mac and System A stand in distinction to other methods available at this time. By design, the Pac Mac is a reverse fluted instrument (Fig. 3). Heated gutta purcha in cartridges is flowed on to the Pac Mac is then inserted into the canal into a space created next to the master cone with a spreader. When the handpiece is activated with the Pac Mac and gutta percha, it creates a convection flow of the material on the Pac Mac that combines with the sealer and master cone to create a homogenous mass of gutta percha and sealer in the root canal space at 5,000 to 7,500 RPM.
A variation of this is to take a master cone that best fits the shape of the root canal system, cut off the excess GP and then just take the Pac Mac into the master cone at 20,000 to 30,000 RPM. Known as System A, named after Dr. Jerry Avillion, this heats the master cone by friction and creates a 3D obturation. Dr. Avillion states “you need a 30,000 RPM slow speed if you want to truly do a ‘System A’ (personal communication) (Fig. 4).
There is no inherent advantage to use a lateral condensation method followed by a warm vertical technique over the SystemB or vertical compaction technique alone.
2) Paste techniques are not recommended (because of the toxicity of many of the paste formulations and a lack of definitive control in obturation) and will not be discussed further. Paste obturation is not the legal standard of care in North America.
3) “Squirt” techniques are non-master cone based in that obturation material is extruded from the cartridge tip end of an EOU or a similar device and the canal backfilled in segments or in one squirt with heated obturation material and compacted with cold pressure. In experienced hands, with an ideal canal preparation, and under the SOM this technique can be used safely and efficiently. The caveat to this statement is that the minor constriction (MC) of the apical foramen must be left in its original position and size to act as natural barrier to the extrusion of obturation material. Transported apices, resorbed apices, etc are not a candidate for this method. In addition, correct needle placement relative to the MC, use of the correct tip and speed of extrusion are critical for success of the technique.
4) Carrier based techniques, in the newer varieties, use a plastic carrier coated with gutta percha and heated and placed to length in canals. In theory, the carrier is centered in canals and gutta percha is circumferentially present around the carrier (Dentsply Tulsa Dental Specialties, Tulsa, OK, USA). In its present form, there is no warm carrier based method at this time that can be bonded. Retreatment of some carriers can be challenging depending on whether the gutta percha circumferentially surrounds the carrier along its length or if the carrier might become wedged with frictional retention along some length of the canal. While warm carrier based methods have their champions, this is not my chosen technique because of the retreatment challenges relative to the costs and the alternatives.
A cold carrier based system exists (SimpliFil, Discus Dental, Culver City, CA, USA) which delivers an apical plug of gutta percha or bonded material (Resilon, Pentron, Wallingford, CT, USA) at the apex over which the canal is then backfilled.
All of the above techniques can be validated in the endodontic literature except paste methods. As mentioned, of the clinical choices available, my chosen technique is SystemB delivered through the SOM and the EOU. The technique is simple, easy to master, requires minimal equipment, is predictable and allows the clinician the option to bond the obturation with RealSeal. The biggest challenge that clinicians new to the technique experience is a void between the downpack and the backfill of the canal. This can be avoided by allowing the tip of the extruder of the EOU to remain in contact with the apical downpack until the material softens slightly before backfill. Initially, backfilling in segments can be helpful and reduce voids. As with any master cone based technique, an excellent adaptation of the master cone and attaining tug back before obturation can go far toward eliminating any other challenges with the method (Fig. 5).
Dr. Mounce lectures globally and is widely published. He is in private practice in Endodontics in Vancouver, WA, USA. Amongst other appointments, he is the endodontic consultant for the Belau National Hospital Dental Clinic in the Republic of Palau. Korror, Palau (Micronesia). He can be reached at RichardMounce@MounceEndo.com.
