A patient came in with pain on tooth No. 13, which had a prior root canal (Figure 1). The diagnosis was previous endodontic treatment with acute apical periodontitis. He said his dentist had a hard time with this case. Upon radiographic interpretation, it appeared that there were some missed canals.
One tip to tell if a canal is missed is to look at where the canal is located in the root. The canal is off-centered compared to the long axis of the root. When the canal that was treated is not centered in the root, other canals usually are present. You also can use cone beam radiography if you are not sure.
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| Figure 1. This pre-operative radiograph shows a root canal performed on tooth No. 13. Notice that the obturation is not centered. | Figure 2: Retreatment was performed in one visit, showing 3 canals located and obturated. |
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| Figure 3: This off-angled radiograph shows the separation of all 3 canals with independent portals of exit. | Figure 4: Dr. Rico Short uses the Global Surgical Microscope to locate complicated canal anatomy. |
I retreated this tooth in one visit (Figures 2 and 3). There were 3 roots/canals located and treated using the surgical microscope (Figure 4). The canals were obturated using warm vertical condensation and Kerr EWT sealer.
This was a very difficult case due to the narrow canals and curvature. The taper on these cases should be kept minimal. I suggest a .04 taper and using many small handfiles before the rotary instruments are used. I prefer at least a size 15/.02 handfile to working length. Any larger file or rotary NiTi file can weaken the root or create a strip perforation.
Please take time to thoroughly evaluate the pre-op x-ray before initiating root canal treatment. If it seems a little weird, send the patient to the endodontist. It will save you time and the patient stress.
What would you have done? Email me at dr.short@yahoo.com, or visit our related posts on Facebook at facebook.com/DentistryToday/ or facebook.com/rootcanaldoc.
Rico D. Short, DMD, attended the Medical College of Georgia (MCG) School of Dentistry to attain a Doctor of Dental Medicine degree in 1999. In 2002, he earned his postdoctorate degree in endodontics from Nova Southeastern University and became a Diplomate of the American Board of Endodontics in 2009. Dr. Short is an expert consultant in endodontics to the Georgia Board of Dentistry and assistant clinical professor at the Dental College of Georgia in Augusta. Dr. Short also has published articles in several magazines and peer-reviewed journals including Dentistry Today, Inside Dentistry, Rolling Out Magazine, Upscale Magazine, and the Journal of Endodontics. He has lectured throughout the United States and the Caribbean. Dr. Short is endorsed by the American Association of Endodontists speakers bureau, and his private practice, Apex Endodontics PC, is located in Smryna, Ga. Dr. Short also has authored a book, Getting to the Root of Your Problem: 365 Days of Inspirational Thinking.
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