Doug Kase
Remember: always use your
Peeso reamer to straighten the coronal aspect of the canal away from tooth
anatomy, such as the furcation in molars or external grooves in bicuspids. |
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 HE
STATEMENT THAT “you must be able to walk before you can run,” has, believe
it or not, a fair amount of endodontic merit. In other words, a fair amount
of preliminary work has to be done when performing an endodontic procedure.
Diagnosis and treatment planning are perhaps a bit of a given and could,
of course, be discussed at length. However, what we all may take for granted
and try our hardest to be conservative about is endodontic access.
We anesthetize, place our rubber dam, pick our newest
bur and proceed to drill a small, conservative hole in a tooth through
which we will instrument and obturate this root canal. What goes around
and around in our head is to keep the access small so as to preserve as
much tooth structure as we can. However preserving tooth structure unnecessarily
may interfere with your ability to perform proper endodontics. Without
proper straight-line access to the canals, our ability to instrument, clean,
shape, and ultimately obturate them is greatly hindered.
Overhanging Tooth Structure
WHEN YOU HAVE attained access to the pulp chamber, it is extremely
important to remove any overhanging tooth structure (see Figure 1). Any
remaining tooth structure diminishes your ability to visualize the chamber
and locate the canals as well as any calcified or extra canals.
If calcified canals are an issue, then straight-line
access is imperative for exploration and excavation, particularly when
you are using magnification. In addition, remaining tooth structure may
force you to pre-curve instruments unnecessarily and gain entry to the
canal from impossible angles. Access to the mesiobuccal roots of upper
molars, for example, is difficult enough without the presence of extra
tooth structure.
Once the pulp chamber has been penetrated, you can
use a large round slow-speed bur in combination with a barrel diamond to
widen the opening into the chamber so that straight-line access can be
achieved.
Straight-Line Access
ONCE YOU HAVE straight-line access, your instrumentation and obturation
procedures will be made easier. If you do not have straight-line access,
you will subject your endodontic instruments to more stress during reaming
or filing because they will be negotiating an unnecessary coronal curve,
which becomes even more accentuated as a result of the overhanging tooth
structure (see Figure 2).
Additionally, if there are any further curves or
bends within the canal anatomy, the stress on the instrument is further
multiplied. If we are dealing with a nickel-titanium instrument, this could
get dangerous very quickly and lead to fracture. When the E. Z. Fill technique
is used, having straight-line access further facilitates our ability to
use our Peeso reamer to continue to straighten the coronal curvatures,
thus making instrumentation less stressful to both the instrument and the
dentist.
It is nice to preserve tooth structure and be conservative
when possible in performing root canal treatment. However, improper access
can lead to a plethora of problems for the dentist and ultimately for the
patient. Proper endodontic access is the key to a successful outcome and
a happy patient.
November-December 2000
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FIGURE 1: After attaining
access to the pulp chamber, remove overhanging tooth structure.
FIGURE 2: Overhanging tooth
structure forces endodontic instruments to negotiate an unnecessary coronal
curve, increasing stress during reaming or filing.
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