Barry Musikant
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have all taken many courses in our quest to do things better, easier, or
faster. Yet, often we never incorporate what we recently learned. Certainly,
I took a number of endodontic courses over the years that emphasized rotary
Ni-Ti instrumentation and thermoplastic obturation. They did not become
part of my techniques and I started to analyze why this was the case.
Departures from Established Procedures
One of the main reasons we do not apply new information is is that
it may represent a sharp departure from the existing knowledge base.
For example, a switch from manual step-back endodontic instrumentation
to a rotary crown-down technique, or lateral condensation with a change
to a heat-carrying applicator. Both represent a significant departure
from the way things were done.
Rotary crown-down presents itself as a superior
technique, but is it better, easier or faster to learn, and is it truly
superior enough to justify its incorporation into your daily routine?
The rotary Ni-Ti crown-down technique has requirements
that the step-back technique does not, including:
-
a light touch that never binds the instrument to the point where it cannot
be pulled out or drawn in
-
a technique that requires constant motion of the instrument
-
frequent replacement of instruments even though you do not see obvious
distortion to them
-
a technique that requires clear tactile perception of when and to what
degree the instrument is binding
Some thermoplastic obturation techniques require the following to be newly
incorporated:
-
the application of a high heat source for a very short time; approximately
2 seconds to a fitted gutta percha point followed immediately by
-
a 3 mm apical push for 5 seconds more after the heat has been applied followed
by
-
reapplication of high heat and withdrawal of the instrument
It Takes Time and Practice
Time and practice are required to achieve the skill to incorporate
these new procedures. Poor application of any of these skills severely
affects the outcome of the procedures. In other words, these new
techniques that might produce a superior result over more traditional techniques
also carry with then the burden of a narrow window of success. A series
of difficult tasks must all be performed well to get a good result.
Potential negative results from the rotary crown-down
techniques include instrument fracture and subsequent blockage of the canal.
Potential negative results from heat application techniques include excessive
heat to the root and periodontium producing pain and tissue necrosis, possible
extrusion of softened gutta percha, and shrinkage of the heated gutta percha
mass yielding a poor dentin-cement interface, something that may occur
without the dentistís awareness of it.
Therefore, the desire to accept a new technique
and, thus, be motivated to learn it, at some point is determined at least
in part by the difficulty of the technique with all its potential drawbacks
versus the predictability of higher quality results. The greater the predictability
of excellent results the more likely the technique will be used again.
If the quality of the results vary widely, the poor predictability of the
technique makes for less acceptance by the practitioner.
The advantages of rotary Ni-Ti crown-down over step
back include:
-
the avoidance of hand fatigue
-
the elimination of distorted curved canals
The advantages of thermoplastic obturation over lateral
condensation include:
-
better adaptation of the gutta-percha to the walls of the root (discounting
shrink-back)
-
less mechanical stress to the root during obturation
-
better looking x-rays, often including lateral canals in non-vital cases
The Ultimate Decision
Ultimately for any procedure, the practitioner must decide whether
the advantages outweigh the disadvantages.
For endodontics, the practitioner can make this
decision in light of the EZ-Shape and EZ-Fill techniques that are easy
to learn. These techniques vary little from the previously known manual
step-back techniques, yet deliver wider tapered canals. These canals are
shaped to exactly fit a fine-medium or medium gutta percha point. This
precise shaping allows the canals to be obturated with a single room-temperature
master point and an epoxy-resin cement of varying thickness that is routinely
delivered as an interface between the gutta percha and the walls of the
root.
The simple reason that EZ-Shape and EZ-Fill are
being adopted by the dental community is that they are in phase with previously
learned knowledge, doing away with traditional shortcomings and adding
those few features that allow the dentist to predictably do endodontics
as well as the best endodontist simply, quickly, and cost effectively.
11/02/1999
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