Allan Deutsch
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 OR
MANY YEARS, I thought the definition of endodontic esthetics was
the filling of the root canal to the radiographic apex. Little did
I realize that I was creating unneeded post-operative pain and possibly
setting up a chronic inflammatory response, which might lessen the chances
of a successful endodontic treatment for my patients. The inflammatory
response triggers the type of pain that occurs immediately after the anesthetic
wears off. This pain is characterized by a sharp intense quality
with throbbing in the affected area. Where was I going wrong?
The endodontic literature during the 1990s reported
that the anatomic apex is often (at least 50 percent of the time) 0.5 to
1.0 mm short of the radiographic apex. The anatomic apex is usually
defined as the apical constriction in the canal at the cemento-dentinal
junction. If the canal is instrumented and filled to this level,
the instrumentation and filling material will not impinge on the periodontal
ligament or the alveolar bone.
The problem was that I was instrumenting and filling
to the radiographic apex (Figure 1). Consequently, I was instrumenting
at least 50% of the time from 0.5 to 1.0 mm past the apex and into the
ligament and bone. For thirty to forty-five minutes, I was using
my reamers to poke tiny holes and rip the periodontal ligament. The result
of this was nasty pain as soon as the anesthesia wore off.
Using an apex locator will enable you to determine
accurately where the anatomic apex is located. An x-ray will not
permit you to locate the anatomic apex. We do not routinely take
working-length x-rays any longer. Because we are no longer instrumenting
to the radiographic apex but rather to the anatomic apex, the amount of
post-operative pain has been substantially reduced.
Now that we are filling to the anatomic apex, we
are experiencing an increase in success rate. Figure 2 shows a gutta-percha
filling pushing through the anatomic apex, which is approximately 2.00
mm short of the radiographic apex. We recently published our office
success rate in a study in the June 2001 issue of Practical Endodontics.
In the article we reported a 94.1 percent success rate.
This is at the very high end of the reported literature. You never
get 100 percent success because cases fail due to root fracture and inadequate
or failing restorations.
Figure 3 is a radiograph of a tooth that is rotated,
showing the bucco-lingual view. You can see that the anatomic apex
is at least 1 mm short of the radiographic apex. Figure 4 shows a
dot of gutta percha at the apical end of the palatal canal. This
dot is approximately 1 mm short of the radiographic apex. The dot tells
us that the canal is curved at a 90-degree angle facing the buccal, so
in actuality you are looking at the end of the gutta percha facing directly
buccal. If you tried to reach the radiographic apex, you would have
to perforate the root and come out the top.
FIGURE 3: The anatomic apex
is at least 1 mm short of the radiographic apex. |
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FIGURE 4: The palatal canal
is curved at a 90 degree angle to the buccal. The end of the gutta percha
is seen as a dot. |
The moral of this article is: if you do more than
3 or 4 root canals per week, go buy an apex locator. I recommend
at least a third-generation locator, Endex by Osada, Root ZX by Morita,
or the locator made by Analytic Technologies.
Happy measuring.
January-February 2002
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FIGURE 1: Endodontic instrument
past the anatomic apex going to the radiographic apex. (Ouch!)
FIGURE 2: The gutta-percha
point is fitted to the radiographic apex and consequently it is 1 mm
long.
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