From: Marga Ree
To: ROOTS
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 ccasion 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

Hi 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

Hi 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 canal configurations.

Stropko JJ.

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

Hi Marga;
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.

RESULTS
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

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 is important.................................
............. (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
syndrome..................

"There are more things in heaven and ROOTS, Horatio, Than are dreamt of in
your philosophy."- Marga