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From: Dr. Glenn A. van As To: ROOTS Sent: Saturday, April 23, 2005 2:56 PM Subject: [roots] 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. Have a nice weekend - 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
Nice photography Glenn.- Wes hi Glenn . nice case presentation Bart ( can you explain the settings of your camera and light source) Glenn, This is a fantastic teaching case with awesome documentation - Stephen Thanks Stephen, I thought it was a good case to show for where the MB2 was when I did it on Friday so I thought I would share it. glad you enjoyed it. - Glenn Hi Bart: I am using the Nikon D70 mounted on the bottom of the scope in Manual mode with the flash at around 1/200 sec with a dual iris diaphragm to act as the shutter. The flash is mounted to the bottom of the scope and is set to ¼ of full flash. In addition I have the ISO at around 320 to 400. WB to pre set. Endo photos down canals are the hardest ones to get. The best ones you get are on wide open accesses with a lot of caries that makes the access big or on ones like this with the composite is in the tooth. Hardest ones for the flash to read are the ones with gold crowns or PFMs with metal occlusion. My light source is the Xenon light source and I love Gary’s mirrors for shining more light into the camera. I don’t have a lens on the camera when it is attached to the scope, just the camera and I use the Xmount because I have it but Gary makes great adapters as well - Glenn As always the documentation is gorgeous.- Thomas Glenn, Very nice case, and world class documentation, as always - Marga Your comments please
