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Finding DB Canal - Courtesy ROOTS
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The opinions and photographs within this web page are not ours. Authors have been credited for the individual posts where they are. - www.rxroots.com |
From: J. Terry Frey, D.D.S. To: ROOTS Sent: Tuesday, May 19, 2009 7:14 PM Subject: [roots] DB canal Can any of you give me advice on how to find the DB canal? Can you see it on this radiograph? I could not locate it. Thanks - TerryHi Terry I see it, is almost the same wl that the mb, one that you open the chamber try to color with methylene blue, with lopes, and if you don't have ultrasound, with a long neck bur. Hope it is of help - Georgette Hi Terry I think there is a DB canal and it is most likely to be located very close to the orifice of the MB canal if not just within it. so you may need to remove some of the GP fro the coronal of the MB to find it. If it isn't there it just might be close to the orifice of the palatal canal but I think the first suggestion is much the most likely - Graham I agree with Grary that in Upper Second Molars the DB canal orifice can be very close to the MB canal orfice and many a times within it and the best way is to trough around the MB orfice and once you have a catch direct vision under a scope is very helpful to widen the fissure and remove the dentin overhang over the DB canal ....but here as Graham says you might need to remove some some GP from the coronal of the MB canal - Sachin Hi Terry, It's an access problem....access extension is critical to finding all the anatomy and there are a lot of really bad suggestions being taught at weekend course all designed to sell bogus overpriced access burs and cater to a mindset that limits exploration, adequate debridement, apical shaping, and predisposes to inside curve perfing. It's not your fault, it's the popular myth that's being hyped and taught by the duplicitous :):):) - Terry Pannkuk
Terry et al .. thanks for the information. This happens to be the dad of my lead assistant and he knows that I had problems and was posting it to ROOTS. This helps me a lot. Getting back there for me is a real challenge. I’ll get it and post - Terry F Good luck!...the other two systems look treated perfectly. Did you extend out to the mesial marginal ridge to catch an MB2? - Terry Pannkuk Terry, I get cross eyed with the DB sometimes because it is palatally located in almost a straight line with the MB. I sort of like Sachin’s example. I can usually determine this by the shape of the crown but not always. When I get this opened, I use the classical access but don’t always look in the classical place. On the case I just posted on my mother, the DB was easy to find since it had gutta percha in it but it was palatally located close to a line between the MB and the P. You probably have seen so many accesses that it jumps out and bites you on the end of the nose. Here’s where the scope really shines over powerful loupes. Terry F, do you have a surgical scope. If no, you need to get one because you’ll be placing implants and doing sinus lifts under them soon - Guy W. Moorman, Jr. DDS I agree that many a times the shape of the crown helps to determine the location of the canals ... smaller crowns in upper second molars have the MB and DB canals close to each other and as you say almost in a straight line or the DB being very close to the MB orfice and one more thing I have learned is that there is nothing like a single canal upper second molar .....at least I am not lucky enough to have them at my clinic ...as a matter of fact a single canal upper second molar in the radiograph warns me for hard work ahead. A Microscope is definitely helpful here but with experience one can certainly locate this anatomy even without a scope - Sachin All you have to do is measure the distance from the MB orifice to the middle of the DB root on a bitewing radiograph. In this case the DB root is clearly outside the access prep wall. It would be a very bad decision to keep the extension small on this case and start digging around next to the MB orifice. Get some better radiographs, expecially a bitewing and measure out the ideal distal wall extension to the DB orifice. This one is clearly underextended. Not fixing the obvious access problem will compound things worse by digging a furcation perf in the center of the pulp chamber floor working blind through inadeqate access that fails to give you a perspective of the pulpal floor map - Terry Pannkuk Dear Terry, I will share my experience for you to evaluate yourself at the risk of Guy labeling my advice "dangerous." In my experience, in molars, both maxillary and mandibular, the mesial-buccal canal is always directly underneath the mesial-buccal cusp. I know you're never supposed to say "always." You're never supposed to say "never," for that matter. But there. I said it. There has even been an occasion or two when I have completely cut down the mesial-buccal cusp all the way down to the gumline in order to find the mesial-buccal canal. Imagine what Dr. Khademi would say about that sacrifice of dentin!! The distal-buccal canal in maxillary molars is much more variable in location than is the mesial-buccal canal. In my experience, the distal-buccal canal is often in the center of the tooth, and I look at the external outline of the tooth structure to give me an idea of where that might be. Basically, I think of maxillary molars as being one of two types -- "fat" or "thin." In a "fat" molar, the three main canals will often form a triangle. And in a "thin" molar, the three main canals will usually form more of a straight-line. I've attached two drawings which illustrate what I am trying to say. But again, there are no always or nevers when it comes to the distal-buccal canal. It is certainly possible that you have already uncovered the distal-buccal canal; it may lie along a line connecting the mesial-buccal and palatal canals. To enter it, remember to angle your file distally upon entry - Patrick Wahl
Pat, I tend to agree with the fact that DB canals have a more variable position, BUT in Terry's case I see the DB root extending beyond his distal access wall. You won't find that DB anywhere near the line you are talking about. The best thing you can do is take multiple angle radiographs and a bitewing, then "READ" them! In Terry's case I strongly suspect a missed MB2 because of inadequate mesial extension and a missed DB because of inadequate distal extension. You have to look at the DB root image on the PA's and bitewings. In my opinion, it's below the standard of care not to take a bitewing radiograph before attempting endo treatment - Terry Pannkuk
Dear Terry P., Hopefully Terry F. will know enough to discount anything I say, and take to the bank anything you say! I was really commenting generally. I'm not able to interpret the radiograph as well as you can, and you are no doubt correct as always. As I am lucky enough to practice within a general practice, I often have bitewings and even full-mouths. I often find them very helpful, but do not insist on them, and perhaps I should. Insisting on an excellent periapical and a bitewing would have saved me a lot of heartache on Monday, when I worked with just a lousy periapical. Terry, you've probably done, what -- about 25,000 cases in your career? It's just a shame that none of those patients are alive today to praise the fine work you did for them!! - Patty LOL.....a couple might still be alive but their dementia prevents them from remembering. :):):) Simply measure the width from the MB orifice area to where the DB orfice on Terry's radiograph is, then look at the mesial and distal walls of the access cavity prep. It is very telling. I think the DB root outline is very clear and you can simply trace a presupposed root canal system to an area where you will expect to find the DB. I'm not particularly clever for figuring that out; I'm pretty good at measuring small numbers between 1 and 5; anything over 10 confuses me. :):):):):):):):):) - Terry P
