Barry Musikant
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 HAT’S
WRONG with making endodontics easier? Well, there is certainly
something wrong if the easier process makes for poorer results. When it
comes to endodontic shaping and obturation, is this the case? Poorer
results would be construed as canals shaped to a smaller diameter, more
distorted from their original shape, or not sealed as well as they
would have been had any previous technique been used.
Rotary NiTi is held up by many as the paradigm of a new
age of shaping because it replaced .02 tapered shapes with
greater-tapered shapes and most often did so without distorting the
original canal anatomy. While the rotary NiTi system produces exactly
what it promises under the proper conditions, we all know at this stage
of the game that the NiTi instruments must be used within a whole array
of limitations that create those proper conditions and, as a result,
require extensive experience if they are to be used safely.
SafeSiders® instruments used in a reciprocating
handpiece are not hampered by the kind of precaution that must be taken
to preserve the integrity of rotary NiTi instruments. By eliminating
the torsional stress and cyclic fatigue that rotary motion produces,
the relieved SafeSiders reamers can be used in reciprocating motion
without any limitations regarding the integrity of the instruments. The
skill that comes with experience in using the SafeSiders is skill in
optimizing their ability to negotiate tight curved canals without
distortion. This quest is not complicated by the need to consider the
possibility of instrument separation because it simply is not an issue.
The SafeSiders sequence addresses the issue of
potential canal distortion by using the initial thinner SafeSiders to
record the canal curvatures. The early instruments duplicate the canal
pathway as they negotiate the curves. We can see the curvature of the
canal recorded in the curvature of the instrument upon withdrawal. By
observing the bent instruments, we learn the location, degree, and
orientation of any curves that were negotiated; our knowledge gives us
the ability to prebend the thicker instruments used later in the
sequence and orient them correctly in the canals. These instruments are
manually driven to the initiation of the curve; the instrument handles
are then attached to the reciprocating handpiece; and then the
instruments are driven safely the rest of the way to the apex. The
canal is not distorted in this enlarging process because the
reciprocating handpiece scribes a very constricted envelope of motion
that does not go through enough of an arc to produce any distortion.
This is not to say that a dentist could not err by ignoring the
resistance of an abruptly shaped canal, or by ignoring the information
that the initial reamers provide upon withdrawal, and as a result
distort the canal apically. However, given the fact that the
instruments are not subject to breakage, the skill required to become
tactually aware of hitting a wall, prebending the instrument, and
negotiating around the obstacle, and then recognizing the curves
recorded in the canal upon withdrawal of the relieved reamers is
routinely acquired with a minimum of proper training.
I am describing a system that requires none of the
precautions and limitations that rotary NiTi requires. The results are
at least as good. So with this system we fulfill the goal of making
things easier without producing compromised results.
The same can be said for obturation. We developed
the bidirectional spiral that drives the epoxy resin that we favor into
the canal. The bidirectional spiral gives us the ability to coat the
canal totally—minus the last few millimeters—without driving any of the
cement over the apex. We then coat a prefitted point and place it to
the apex. Between the prefitted coated point and the thoroughly coated
canal walls, an excess of material is being squeezed into the canal,
and the resulting pressure forces excess cement laterally into any
accessory canals that may be present and then out of the canal via the
coronal escape route. Once the cement is placed in all the nooks and
crannies of the canal system, it sets without any shrinkage. In fact,
the cement expands slightly as it warms from room temperature to body
temperature. The cement itself bonds chemically and physically to the
walls of the canal as well as the gutta percha point. In this way, a
single well-coated gutta percha point helps produce a three-dimensional
fill that is at least as good as any thermoplastic fill or one produced
via vertical and lateral condensation.
These are simpler approaches, but a major part of
the thought process that went into them was the clear concept of no
loss in quality as measured by better shaping, less distortion, and the
creation of an optimum seal.
Those who advocate more complicated systems should
clearly show what benefits are derived from the complexity in terms of
better shaping, less distortion, and a superior seal. To date this has
not happened. In the meantime, the consequences of a simpler system
automatically make the dentists more qualified because there is less
that can go wrong.
From this simpler base, there is no limit to how
good the dentists can get simply by practicing on extracted teeth and
realizing the full potential of these simpler approaches. It should
accelerate the learning curve and make the dentist more confident as he
is challenged by more complex endodontic situations.
We conduct our usual array of courses, from free
workshops lasting 2–3 hours to workshops lasting two full days, during
which the hands-on portion of the course lasts for 11 hours of the
entire 17-hour schedule and the dentist on average works on 15 to 20
teeth, at least half of them under a microscope, gaining access,
shaping, and obturating them. If you are interested in any of these
courses, call 212-582-8161 for the free workshop or 201-487-9090 for
the two-day workshop.
April - June 2007
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I am describing a system that requires none of the precautions and limitations that rotary NiTi requires.
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