Doug Kase
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 MONG
ALL THE endodontic cases that we all do, there is always the one that turns
into that horror movie called “Attack of the Killer Root Canal”!
It’s the one we begin with a good deal of confidence and an internal voice
that says, “I can do that—no problem,” but we finish wishing that we could
call our dental school instructor to bail us out, have him pat us on the
shoulder and tell us it’s OK. With that horror movie in mind, it
is important when beginning treatment of an endodontic case to make sure
that you have looked at the radiograph not only for the diagnosis but also
to assess the clinical picture of the tooth in question as it appears in
the mouth. Restorations, tilts, rotations, and gingival root angulation
all become factors when you are gaining access and searching for canals.
The radiograph is important, but it is only 50 percent of the road map
we use to plan our trip to the pulp chamber and beyond.
Looking at root angulation and emergence profiles
at the gingival margin is particularly important in cases with calcified
pulp chambers and when you are searching for calcified canals. Periodontally
probing the tooth while gaining access will give you a visual indicator
of the external anatomy and allow you to judge how far you should excavate
the area while searching for canals. This knowledge is very important
in maxillary molars, where the position of the palatal root may be shifted
distally, or when you are looking for the mesio-buccal canals. Also
compare the location of existing canals in the access cavity with the external
shape of the tooth. For example, comparing the external lingual surface
of the tooth and the position of the wider buccal canal as it appears in
the access cavity will help you detect the presence of a secondary lingual
canal in lower incisors. If there is more tooth structure on the
lingual side than the buccal side and the canal is oriented to the buccal,
then suspect an extra canal. Check the position of furcations and
measure them not only on the radiograph, but clinically as well to avoid
perforations. This measurement is especially important if the chamber
is calcified or the coronal aspect of the tooth is obscured on the radiograph
by a radio-opaque restoration. Trans-illumination from the buccal
and lingual will help immensely.
Look at teeth for rotations and tilts that are likely
to throw off your orientation when drilling toward the pulp chamber.
Severe mesial tilts of lower molars can move the distal canal into the
mesial position. If you’re not aware of the orientation, you may
drill farther distally in search of a canal that doesn’t exist and perforate.
Rotations obviously also shift the positions of canals, so be aware when
gaining access.
When we are doing root canal we cannot have blinders
on. We can’t let our confidence keep us from looking at the whole
picture, both clinically and radiographically. Each component can
have great value in determining the ultimate success or failure of the
case.
“Kase Presentation”
A PATIENT presented to our office with a calcified lateral incisor,
tooth #10, which was excavated deeply and widely for the canal (Figure
1). Using the endodontic surgical microscope, I was able to find the canal
and also locate a small perforation on the distal aspect of the excavation.
I instrumented the canal and fitted a medium-large gutta-percha point to
the apex. I mixed MTA cement and, using an apico amalgam carrier
and fine pluggers, packed the cement around the gutta-percha point (Figure
2). After twenty minutes, the MTA cement was hard enough to remove
the point, and I sealed a damp paper point in its place for 24 hours. When
the patient returned, the MTA was fully set and I removed the paper point.
I then sealed the canal, using EZ-Fill cement and a single cone of gutta
percha (Figure 3), and post-prepped on that visit (Figure 4).
FIGURE 1: Tooth #10, excavated
deeply and widely for the canal.
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FIGURE 2: MTA cement packed
around the gutta-percha point.
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FIGURE 3: Canal sealed with
EZ-Fill cement and a single cone of gutta percha.
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FIGURE 4: The tooth after
post-prepping.
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February-March 2003
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QUIZ
Identify the foreign
object shown in the x-ray below. Is it . . .
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a surgical pin
-
a dislodged silver point
and retrograde amalgam
-
a fragment of endodontic
endosseous implant
-
a traumatic projectile
fragment
-
every parent’s nightmare—the
dreaded nose stud!
(Click
for the answer.)
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