by Barry Lee Musikant, DMD
For more on this topic, go to www.dentaleconomics.com and search using the following key words: endodontics, hand files, obturation, apical pressure, Dr. Barry Lee Musikant.
As we know, adding endodontic procedures to your office will build your practice. However, rotary NiTi endodontic instrumentation systems generally come at a high cost and often have unexpected instrument separation. There are lower cost alternatives to these expensive systems.
One such alternative is the use of hand files. Even though these files are more cost-efficient, they bring on a great deal of hand fatigue and additional obstacles. Switching from hand files to a relieved reamer, you will negotiate canals with at least half the resistance you have previously encountered.
You will be able to tell when you are hitting a wall and when you are in a canal. Knowing this gives you the ability to pre-bend any of the instruments to negotiate around almost all of these impediments.
These reamers give you the ability to use them with both a tight manual watch winding stroke or in a 30º reciprocating handpiece. Utilized in either of these ways, torsional stress and flexural fatigue to the instruments are virtually eliminated, doing away with the two main causes of instrument separation.
These instruments, limited to a tight arc of motion, are not subject to breakage and can be used several times before replacement, reducing their costs compared to rotary NiTi by about 90% on a per use basis. Canal distortion is minimized by their great flexibility, their minimal shape memory, and the point contact they make at the tip when confined by the canal walls.
Because breakage is not an issue, the canals can be shaped to greater dimensions than those done with vulnerable rotary NiTi systems. Greater canal preparations provide for more effective irrigation that leads to cleaner canals and higher success rates.
The same reciprocating handpiece that creates shaping via rapid 30º oscillations of the instruments is used to activate the irrigants’ potential cleansing effects. Used at 3,000 to 5,000 cycles per minute, more than enough sonic energy is imparted to the solutions to remove the smear layer, kill any bacteria present, and digest chemically the residual tissue that may not have been removed mechanically.
From a treatment planning point of view, this approach is good for all situations. There are no exceptions that could lead to iatrogenic damage.
As several articles have pointed out, hand instrumentation particularly in curved canals is often superior to rotary instrumentation. Please note that the oscillating motion generated by the reciprocating handpiece is essentially the same motion generated manually, but with far more efficiencies.
Obturation is the second part of endodontics that can be accomplished with simpler, more predictable techniques that increase safety while substantially reducing costs. When the canals are prepared to a 35 with a 25/.06 overlaid taper, they are sufficiently shaped to accept a medium point, one with a taper between .05 and .06.
A simple way to produce a three-dimensional fill is to thoroughly coat the canals with an epoxy resin cement using the bidirectional spiral, a cement applicator that has the ability to thoroughly coat the canals without driving the cement over the apex.
The point is fitted to the canal at the correct length with tugback. It is then liberally coated with cement. If done correctly, excess cement should escape coronally as the master point is placed into position. The cement is of low viscosity.
As the prefitted tapered point is placed, the cement is first driven laterally into all the nooks and crannies along the length of the canal walls before the excess escapes coronally. The apical pressure is insufficient to violate an intact pdl; consequently overfills are avoided unless the canal was overinstrumented. In nonvital teeth where an intact pdl may not be present, some cement can go into a periapical area.
However, the macrophage that are always present in these situations will resorb the cement in a matter of months as the areas heal uneventfully. The placement of a well-coated point will produce varying thicknesses of peripheral cement, but the research clearly demonstrates that this does not compromise the seal along the length of the canal.
If the thought of a single point in a tapered canal concerns you, you can simply use a spreader with light apical and lateral pressure to create spaces for one or more well-coated accessory points. The fact that these fills are entirely room temperature is an advantage over thermoplastic approaches.
Placed at room temperature, both the cement and the gutta percha warm to body temperature, expanding about 1.75% in the process. This is a far better scenario than the 4% to 5% shrinkage that occurs when heated gutta percha cools to body temperature. As the research has clearly shown, shrinkage of less than 1% is sufficient to create a space for the ingress of bacteria.
In review: Shaping and obturation can be accomplished by far less complex and expensive means than rotary NiTi instrumentation and thermoplastic obturation, both of which dramatically increase the cost of these procedures. By substituting a simpler armamentarium, we are not compromising the final results.
In fact, the simpler armamentarium often leads to superior results due to the ability to shape the canals to greater dimensions (Figs. 1 through 3).
Within limits, the greater the preparation of the canal, the lower the bacterial count, the more predictable the obturation, and the higher the success rate. The strongest correlation for success is the reduction in the bacterial population brought about most effectively by wider apical preparations.
Using a 30º reciprocating system for shaping increases the dentist’s confidence that the instruments will remain intact, and gives him or her the further confidence to shape the canals to wider dimensions. These relieved instruments encounter far less resistance along the length of the canal, allowing the instruments to gain full length far more rapidly than the traditional use of files.
These tools increase the safety of your endodontic procedures, shape the canals to wider dimensions without distortions, and reduce your costs immensely. By adopting this approach you will:
- Virtually eliminate separated instruments
- Eliminate inadequately prepared canals
- Improve your irrigation techniques
- Minimize overfills
- Minimize stress to the root resulting from excessive apical or lateral pressure
- Eliminate the stress to the ligament resulting from excessive apical heat
- Produce a superior seal along the length of the canal
- Reduce procedural stress levels
- Enjoy and reap greater rewards from endodontics
It definitely pays for you to learn more about these systems. You’ll gain in confidence while reducing your overhead. Please keep in mind that if the results are equivalent or superior, and the techniques used to attain those results are less complex and less expensive, the very definition of progress has been fulfilled.
Dr. Barry Lee Musikant is a partner in the largest endodontic practice in Manhattan. Contact him at [email protected]. To view examples of complex anatomy shaped in a nondistorted manner safely and effectively with the SafeSiders instruments used in the EndoExpress reciprocating handpiece, visit www.edsdental.com/xrays.
