Special location MB2
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From: Marga Ree
Sent: Friday, February 18, 2005 4:15 AM
Subject: [roots] Special location MB2
Today I did a maxillary first molar with a special location of
the mb2. In first instance I throughed the line between the white
and grey dentin, but I coudn't find an orifice. I decided to
enlarge the mb1 orifice a little bit, and there I found my mb2,
in the middle third of the mesial root there was a division
in 2 canals. Perhaps this is not so special for you guys, but
for me it was the first time !! - Marga
Lovely result as usual Marga.
Just makes us wonder how much of this is out there that we miss,
yet things still heal. - Bill
Marga...you could do a root canal if I need one.- Joseph Dovgan
Ain’t that the truth. Aside from the lovely endo, I also love how
Marga gets that resin to adapt to the gp without the slightest hint
of a void between the two materials.
That is a neat anatomy.I find it once in a while, but not often- Mark
it is special for me too, Marga ;-) - Marcos
Nice case, nice find - Mark A Massey
What a nice case. I have found MB2 in the MB1 orifice. I have on
occasion found it inside the P orifice as well.
Chilling thought: I wonder how many I have not found? DougR
Precisely Doug, that was what I was thinking too....................
......... So it can even be located in the palatal orifice as well,
I know John Stropko mentioned this in his paper
in the JOE of november 1999. Thanks for your input ! - Marga
Absolute work of art marga. Do you ever mess one up ? what made
you decide to enlarge the orifice. I think I would have troughed
the line, and not finding the mb2, would have proceeded on the basis of
3 canals. Was there something anatomically that gave you a hint? - gary
Of course I have messed up cases, which I secretely and carefully save
in a hidden file on my computer :-))).................I decided to enlarge
the orifice after I did the endodance at a midroot level of MB1, and
noticed a sweet, sticky spot in a more palatal direction.
Thanks for the nice compliment !! - Marga
Hi Marga, well, this might be an achievement, however, you're going to
find it documented in JOE, Nov.2001, where MB2 usually starts as a common
orifice with the MB canal, then they separate as you just found.
this is classified as a type V canal. - Hend
Thanks for your reference. Maybe I overlooked something, but after
reading the paper you mentioned in your post, I couldn't find anything
about a so called Type V in this paper, neither the statement that MB2
usually starts as a common orifice with the MB canal. Another remark,
you are referring to an in vitro study in which the authors
investigated 45 first and secondary molars. I have done a decent
number of max. molars in my professional career, and it is not my
experience that this type of location is very common. See the comment
of Mark Dreyer, he has also the same experience.
Hereby you find an abstact of an in vivo study of John Stropko,
he examined 1732 max. molars, and mentions in the discussion that:
"On occassion, MB2 shared an orifice with MB1. When there was a
shared, or common orifice, many times the opening was more oval
in shape". and "it would have been very difficult, if not impossible,
to observe the MB2 orifice if the microscope was not being utilized"
What is your clinical experience concerning the location of the
MB2? - Marga
J Endod. 1999 Jun;25(6):446-50.
Canal morphology of maxillary molars: clinical observations of
Boston University School of Dental Medicine, MA, USA.
An examination of 1732 conventionally treated maxillary molars was
made in an attempt to determine the percentage of MB2 canals that
could be located routinely. The teeth examined were 1096 first
molars, 611 second molars, and 25 third molars. The results were
recorded on a modified computer program over an 8-yr period of time.
An interesting trend was noted. The MB2 canal was found in 802 (73.2%)
first molars, 310 (50.7%) second molars, and 5 (20.0%) third
molars. It occurred as a separate canal in 54.9% of first molars,
45.6% of second molars, and joined in all third molars. However,
as the operator became more experienced, scheduled sufficient
clinical time, routinely employed the dental operating microscope,
and used specific instruments adapted for microendodontics, MB2
canals were located in 93.0% of first molars and 60.4% in second molar
First, yes type V canal is not mentioned in the paper; this is an
additional information I got from Harty's endodontics. Second,
the following abstract from the paper may be helpful.
In most teeth the MB-2 canal orifice was located without
difficulty but the canal could not be negotiated
unless some dentin was removed from the orifice level
apically. - Hend
I tend to disagree here. I think the authors meant that in
order to be able to negogiate the mb2 canal, you need to
remove some dentin from the orifice level of the pulp
chamber floor in an apical direction.
Their results show namely that:
The location of the MB-2 canal varied considerably in
relation to the main mesiobuccal and palatal canal
orifices. The location of all MB-2 canals is plotted
graphically in Fig. 2, and the mean distances are
summarized in Table 2. In 50% of the teeth the MB-2
canal was located within 0.5 mm from the mean mesial
and palatal distances, as represented by the square in
the center of Fig. 2. The MB-2 canal was consistently
mesial to or directly on the M-P line. - Marga
Since Paul W. reads ROOTS, I want to tell him he did a
good job mentoring Marga as a scientific endodontist.
She does not just quote the literature after reading
an abstract she reads the whole paper and analyses it
thoroughly. Regarding her clinical ability he probably
had not much to do with it, as she has "god given"
unbelievable talent and commitment. But it takes a great
educator to know who to accept into a program or not.
Professor Wesselink I salute you. ACTA is a class ACT.
We are very lucky you take time to contribute
from time to time in ROOTS. - Benjamin Schein
Ben, thank you for the compliment to Marga and me.
One thing everybody should realise: Never go by the abstract
only but read the full paper and scrutinize the methodology
and check if the conclusions are based on results.
You read an abstract only to see if the paper may be worth
reading in full. That is why I am not so interested
in all these IADR abstract we have seen lately at ROOTS.
It only told me I have to watch for some papers that
may come up in the future but nothing more. - Paul Wesselink
Dear Marga , thanks for posting your fanastic work!!!
Could you please tell me about your shaping protocoll?
- Jörg Schröder
Hi Jorg , Danke schön !!
My shaping protocol:
Glide path # 20
K3 shapers: 25/12, 25/10, 25/08
GG drills 4, 3, 2
K3: 35/06, 30/04, 25/06, 20/04 (VTVT sequence till WL
is achieved) Depending on canal shape, recapitulation of
above mentioned files, I usually finish with a min.
file size 30/06, apical finishing with handfiles, apical
gauging with lightspeed. - Marga
MARGA, when you gauge with LightSpeed, do you take the
belly OR the tip of the LS file to your WL?
I know this is of not relevance in smaller LS sizes, but in
larger ones it may give half a mm difference,
and if we wanna be as acurate as possible, even half a mm
............. (us doing endo are crazy....)
good question, huh? (somebody had to say it ! ;-))- Marcos
Great question :-)) I just gauge with Lightspeed, I usually
don't use them in a handpiece. When a LS belly drops through
the foramen, it is very typical feeling. I gauge with several
sizes, that gives me a picture of the very apical part of the
canal shape. Of course I am I beginner with this LS gauging,
and I am practicing very hard to become as experienced as Rob,
who really can become one with the canal, I am secretely
envying him for that ability......................:-))
Yes we are crazy, and suffering from the roots related addiction
"There are more things in heaven and ROOTS, Horatio, Than are
dreamt of in your philosophy."- Marga