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Tough distal canal
From: Marga Ree
Sent: Wednesday, December 06, 2006 8:52 PM
Subject: [roots] Tough distal canal
This patient was referred because of persistent complaints when
biting on 36. Her dentist had performed rct some months ago,
because of these complaints. According to the dentist,
it was a vital case, but after the treatment, she still wasn't
able to use the tooth. As you can see on the pre-op rads, the
distals were short, and the apical shape of the mesials looked
weird. It has been shown in the lit that after vital pulpectomy,
the best success rate has been reported when the procedures
terminated 2 to 3 mm short of the radiographic apex. I have my
doubts about this, and this case is an example that staying
short can result in persistent complaints.
I decided to retreat.
The distals were very difficult to negogiate, and I was pretty
sure there was a sharp curve to the distal.
Anyhow, after 6 weeks of Ca(OH)2, she was nearly symptomfree,
so I decided to fill today. Strange anatomy, I am not sure if
these were the original canal configurations, and two
voids in the BU...:-( But the patient is happy, and can use
her tooth again - Marga
Marga, what a great service to the patient . Excellent.
Have you been able to negotiate the beginning of the lateral
canal? did you use solvents? - Jörg
Thanks Jörg. Yes, I was able to negotiate at least a part of
the apical curve, my file came out with a very sharp bend at
the end. I was not able to obtain patency in the distals.
I used choroform, as I usually do in retreatment cases - Marga
Dear Marga Nothing to say but excellent!!
thanks for sharing, your work is inspiring!!!
could you tell somethig about obturation materials and tech
in this particular case?. The apical contron on mesials looks
great - Carlos Heilborn
In this kind of retreatment cases, it's all about trying to
"don't make it worse". The previous dentist used too stiff
instruments, Rob Kaufmann hit the nail on the head,
see his post, he is a very keen observer, and really knows
how to explain things. In these cases, time and patience are
Here is my approach:
Precurve files # 08 and 10 with an endobender or a nail
clipper I learned this from Gary Carr. With the latter, you
will be able to put a tiny curve, only the last flute.
You have to do this under the microscope. Then, pick a
little with these, while endodancing 360 degrees, use EDTA
and NaOCl alternately, and try to find a sweet spot.
Switch between regular files and C files. I love the C+
files for this purpose. Use lots of new files.
As soon as you feel a catch, try to work the file down a
little bit, increments of 0.5-1 mm, and switch to a regular
# 06 or 08 file. Sometimes I use a M4 handpiece to loosen
it up, as soon as a have a path. If I am in
doubt, I take an radiograph to check if I am on track.
I filled with resilon, using System B for the downpack and
the Obtura gun for the backfill - Marga
I think this is a great example of classic "internal transportation"
of the canal - but you managed to save the case nicely. .
If you look closely at the final mesial fill, the mesial
canals look trifid ( or more!). The original operator used
instruments that were obviously too stiff. The result was that
the canal straightened at the terminal portion and the final
fill looks "fanned out". Fortunately, there was no perf.
The distal was straighted in a similar manner except that you
managed to get around the distal curve (which shows great
Salvaging those mangled cases is probably the most difficult
treatment that you can do. Nice job.
You know, we all have a tendency to take a quick look at an
endo radiograph and judge it in an instant. In this case someone
may say "Oh my gosh , who did THAT!?" Unfortunately,
what you can't appreciate with a fast glance is that many of
these awful looking cases are actually "saves" that took a lot
of talent and effort to treat. They sure don't look pretty
in the classic sense, but the fact that the case is asymptomatic
and shows no pathology is really what matters. We all need to
be more careful when judging radiographic appearances.
Many succesful retreat cases are just plain ugly - Rob
Hi Marga ................Fantastic case. Just a few queries....
1:What do you think about the final size of the mesial canals
in relation to the root strength of the remaining structure
in this case .
2: Such a apical curve is a common presentation in the distal
canals of the lower molars. Until now I was under the impression
that the file would be curving at the apex and many a times
I have found that it does but here in this case I see that the
files appear straight at the apex and so does the obturation and
the apical curve in the distal root is evident in the form of a
lateral canal or bifidity. So were you able to instrument this area ?
My viewpoint regd. the 2-3 mm short in vital cases.............
....if we keep in practicing short in vital case we might have
trouble in instrumenting this area in non vital / infected
cases from the sheer lack of practice and be prone to failure .
Now this might not hold true for experts like you and many others
on Roots but for the many of us we still are learning
and should practice in all cases what we would be doing in the
tough cases........... just my humble viewpoint - Sachin
if we keep in practicing short in vital case we might have
trouble in instrumenting this area in non vital / infected cases
from the sheer lack of practice and be prone to failure
I think you raised a very good point here, thanks for your input .
Some lecturers and dental schools advocate to stay short in vital
cases because it may be difficult to negotiate the last 2-3 mm.
Of course it can be harder to negotiate an acute apical curve,
but with the right technique and instrumentation sequence, it is
doable. I don't undertsand this reasoning, because the very same
arguement applies to retreatment cases, in which it is of paramount
importance to negotiate the last 2-3 mm..............And we know
from our clinical experience how difficult it is to regain length
and negotiate the very apical part in retreatment cases
that were instrumented short, because we not only have to deal with
the original uninstrumented apical part, but in addition with set
sealer and a ledge which we have to address and bypass.
So staying short in vital cases can complicate retreatment,
as I showed with this case.
What do you think about the final size of the mesial canals in
relation to the root strength of the remaining structure in this case .
The root strength may indeed be compromised. The canals were already
pretty much enlarged, as you can see on the pre-op rad. I took care not
to enlarge the mesials further, but there was an isthmus between the
mesials, and the canals were pretty oval shaped in bucco-lingual direction.
So I throughed the isthmus, and while negotiating the apicals part of
the mesials, it felt if there was a pretty large interconnecting fin
between the mesials. This may partly explain the fat filling in the
apical part of the mesials
So were you able to instrument this area ?
As for the distals, the previous clinician has probably instrumented
with too large and too stiff files. So the original canal configuration
was ledged. I thought I was able to negotiate at least a part of the
distal apical curve, my files came out with a very sharp bend at the end.
I was not able to obtain patency in the curved distal. I am pretty sure
that the original POE must have been located on the distal aspect of
the distal root, and not apical. I think the latter is a
" man-made canal"...:-)) - Marga