August 1, 2007
by Rich Mounce, DDS
If, when injecting a flowable sealer (like RealSeal sealer or EndoRez), an air bubble (void) forms, how do you get around that? Do you have to remove it all and start over?
How much sealer and how the sealer is applied is indirectly related to both the reduction of sealer extrusion and optimal sealer hydraulics in warm master cone based techniques (such as the vertical compaction of warm gutta percha as well as SystemB and the extrusion of obturation material in a “squirt technique” with an instrument like the Elements Obturation Unit (SybronEndo, Orange, CA))? Applying sealer correctly can optimize both of these techniques.
The first question to answer is whether the application of sealer to fill the entire canal is necessary before the placement of either a single cone obturation or a warm master cone technique followed up by a downpack. I am an advocate of warm obturation techniques that are master cone based, in other words, not warm carrier based techniques and not single cone techniques that rely upon a single master cone placed passively to express sealer into all the ramifications of the canal space. In a single cone technique, the clinician is dependent on an intimate cone fit to create the needed hydraulic movement of sealer into all of the various ramifications of the canal space. This is hopeful more than predictable and depends largely on the exact placement of sealer with a syringe like the Skini syringe and the Navi tip (Ultradent, South Jordan, UT). The amount of sealer and its placement are critical for preventing unnecessary extrusion as well an adequate dentin bond with an obturating material such as RealSeal (SybronEndo). In essence, the concept of filling an entire canal with sealer and placing a single cone will require a significantly greater volume of sealer than a technique which will intentionally fill all the ramifications of the canal with a core material like RealSeal. In essence, the concepts involved in both methods are significantly different. Less sealer will be needed in a vertical compaction technique, a straight SystemB technique, or even the “squirting” of the canal with the Elements Obturation unit.
With this background, to answer the question, if an air pocket or void should occur in the canal with the extrusion of sealer with the Skini syringe and a Navi tip, the event is really a “non event” as the placement of the master cone into the canal which should always be passive, slow and gentle should allow the air bubble to be expressed coronally and without effect to the patient. Conversely, if the clinician should force the master cone to length quickly, it is possible that sealer could be pushed beyond the root end and cause discomfort, but this is virtually always, completely avoidable. Should the clinician suspect that a void has occurred with the placement of sealer, irrespective of whether they are using a single cone or warm master cone based downpack technique, the placement of the master cone would and certainly should allow the sealer to be moved circumferentially and the air bubble to move in a coronal direction. In addition, if one is using an accelerated setting sealer, the time from the placement of the sealer to the placement of the master cone should be very rapid so as to not allow the sealer to begin to set up and act as an obstruction to the placement of the master cone to its full apical extent. If one is insistent on using a single cone technique, if a void has occurred in the sealer placement, after using a master cone to remove the air bubble, sealer can be reapplied if there is any uncertainty as to the equal dispersion of sealer throughout the canal before cone placement.
In summary the occurrence of a void when expressing sealer from a syringe like the Skini syringe and Navi tip is overcome with the correct placement of a master cone and if the clinician is using warm down pack techniques like vertical compaction and SystemB technique, any voids of air should be completely removed during the process.
Dr. Mounce has no commercial interest of any kind in any products mentioned in the article.