Barry Musikant
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SYSTEM of endodontic instrumentation is created to provide a shape to a
canal that assures that it has been thoroughly cleansed by both the instruments
used and the irrigating solutions applied with them. The system is composed
of a series of instruments used in a specific sequence delivered to the
canal either manually or by a powered handpiece. Each of those instruments
should ideally have a design that optimizes its usage. The design, delivery,
and sequence (DDS) of the instruments should support one another in the
most efficient and safest way possible.
Design
CANAL SHAPES with tapers of .06 mm/mm or greater are more likely to
be cleansed than the traditional .02 mm/mm tapered canals because greater
tapers remove more pulp tissue, increase the ability to place irrigating
solutions closer to the apex, and increase the intimate contact of the
irrigating solutions with the walls of the canal. As the taper of the canal
increases, the surface tension between the walls of the canal and the irrigating
solutions decreases, allowing greater flow of the irrigating solution producing
more effective cleansing action.
Delivery
LEARNING TO USE these instruments in a safe manner requires the ability
to develop a light touch that prevents excess engagement at any one time.
The “touch” that one must develop has no clear parameters other than it
must “feel right.” Poorly defined parameters mean that fewer practitioners
will get it just right.
Long-rooted teeth with tight canals and one or more
curves further complicate successful instrumentation. Most problematic
is the fact that NiTi reamers and files are prone to fracture when subjected
to levels of torque, flexure, and fatigue that are close to the normal
forces that must be applied. Consequently, NiTi rotary instrumentation
is a technique with a very narrow window of success. If the technique is
not performed exactly right, the result may be a fractured instrument locked
into the canal space.
Sequence
THE SEQUENCE of the instruments should be compatible with their strengths.
If a rotary NiTi reamer is used in a crown-down fashion, the potential
of high dentin engagement exists. The greater the engagement, the greater
the stress to the instrument, stress that is magnified further if the instrument
is negotiated around a curve.
Proper sequencing ensures, first, that the extra
work each instrument must do falls well within its ability to do it without
fracturing and, second, that the practitioner can easily tell when to progress
from one instrument to the next. The design of each instrument in the sequence
should further enhance its ease of use.
Results
THE RESULT of properly designed instruments used in the correct sequence
is a system that shapes canals safely, simply, predictably, effectively,
and economically. The impact upon you personally is far less stress, greater
pleasure in performing the procedures, and more free time—meaning either
greater financial productivity or increased leisure time.
To learn more about properly designed systems that eliminate the endodontic
stress in your life, e-mail me.
November-December 2000
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