From: Dr. Glenn A. van As
Sent: Saturday, April 23, 2005 1:57 PM
To: 'roots
Subject: Uncovering the Mb2 canal , a journey documented

Here is the original story as posted on Dental Town

Hi folks:  so often I read about not finding MB2s in upper molars or not knowing where to look or how to uncover
them.  I had a light day yesterday so I had a chance to fully document this case for you.  Hopefully it helps to not
only show where the MB2 is located, the angle it initially takes but also what the microscope can show for endo at
high mag.

This was a 45 year old lady who has had intermittent lingering pain to cold and spontaneous pain on upper left 2nd
molar with large resin in place.

I opened the tooth and found DB and Pal canals to be vital and easy to find because of bleeding. MB1 and MB2 were non
vital and not easy to see at all. I used  an Ultrasonic tip to uncover the MB1 canal which was not on the same plane
as the DB canal (Not a straight triangle) and so I assumed that there would be an MB2.  The tip used is called the
Carr Killer Ultrasonic tip (www.eie2.com) and it was in the EMS mini endo unit.

Now to look for the MB2 canal I placed water on the floor of the pulp chamber and quite often you get a chance to
read the dentin map which is subtle shades of the pulpal floor that allow you to see where the canal may be.
Typically it involves shades of grey that lead to the canals.  In this case something was visible but not clear.
Next thing to do is trough 2-3mm down following the dentin map and have another look.  There was the tell tale white
line (tissue ) between the uncovered MB1 and the position where the MB2 would be which is Mesial to a line drawn
between the MB and Palatal so almost always you have to remove some of the mesial wall of your access.  Its
interesting to note how I had to trough 3mm down to get a good view, and also note the angle that the MB2 initally is
entered at, USUALLY MESIAL AND LINGUAL to that of the MB1.

The MB1 and MB2 were completely separate even though the post op film was straight on and didnt separate them.  I can
usually tell by irrigation.  If you place bleach down the MB1 canal and the MB2 fills up as well, then suck back and
see if the MB2 dries up.  This means there is a connection.  Of course you can also tell by putting two files into
both canals at the same time.  These two were separate portals of exit so it was good I found both.

My file system which really is unimportant is that I use K3 VTVT (alternating between 06 and 04 tapers changing the
tip size each file as well so its called variable tip and variable taper).  This has been shown by John McSpadden to
reduce file breakage.  Typical sequence is

Hand file 06- 20 to apex with Glyde
.12 , .10,. .08 tapered coronal shapers (17mm length) to open coronal 1/2
.04 #40
.06 #35
.04 #30
.06 #25
.04 #20
.)6 #15 (if needed)

Then taper back from there to gauge the apex with a file.
In this case MB1, MB2, and DB canals filled with 04 #35-#40 tips cut specifically with a gauge
Palatal canal 06 35 tip

EWT sealer, System B downpack and Obtura backfill to obturate.
Note the nice accessory canals in the apical third on the DB and Palatal canals.
Time to complete case....7.5 mins including photos.........
Nah just kidding yah.......90 mins.

I hope that you find this interesting and this is pretty standard for me to find a 4th canal in a molar both
maxillary and mandibular.first and second molars.


Glenn

The photos are of the case and at the end is a crude drawing of the endo access and where the MB2 is located















Glen, Just wanted to let you know that I thought your MB2 explanation was very helpful. As a GP you don't always like
to ask these questions, but your presentation was very much appreciated. Thank You for taking the extra time to
document your procedure.- Stephen

Wonderful documentation Glenn! You really are an artist! Congrats! - Liviu

Thanks Liviu, I am trying to improve the level of my presentations so they look professional.  I worked those images
in an image editing program (not photoshop) and the beveled edges and drop shadow add to the overall look.
I appreciate the kind words my friend. - Glenn

Glenn, awesome ! -   Fred