|Case of the Month
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November 2002 – The Perio-Endo Lesion. How Do we Treat ?
November's case of the month deals with a Maxillary first molar tooth that was referred for endodontic treatment. Pulp tests produced negative results and a diagnosis of necrosis was made. There was a large periapical lesion associated with the furca and a history of extraction of the Maxillary 2nd Molar. Periodontal probing showed deep pocketing in the distal furca area but other areas were normal. (This was to prove very significant.)
Preop - #16 Note Mesial root anatomy
Preoperative radiographs revealed a mesial root of considerable length and seemingly impossible dilaceration Not only was the mesial root long and curved, it had a sharp 180 degree curve right at the apical end. Furca lucency was present.
After considerable efforts, I managed to get a small file to the MB apex. With slow filing motions and lots of lubrication progress was made in attempting to shape the MB canals and maintain patency. The root had a second curve right at at the apex - in the opposite direction!
Although I was not as happy as I could be with regards to the palatal canal fill, I believe that the rest of the case was done as well as could be expected. I had considered using rotary Ni-Ti instrumentation in the MB root but at that time I was relatively new to Ni-Ti rotary and I was not confident that the canals could be shaped without instrument separation.
Post Op #16 - 4 canals
The case was filled with the standard vertical compaction of Warm Gutta Percha - Schilder Technique. Although I could not get my Pluggers to within the recommended 4-6 mms. in the MB root, I thought the results were reasonable under the difficult circumstances. The case was sent back to the referral and appointments were scheduled for placement of a crown.
6 months later the patient returned with apical swelling, drainage from the distal and buccal furcation areas and percussive tenderness. I was disappointed in the negative turn of events. At that point I considered conservative or possibly surgical endodontic retreatment options because the difficulty of the anatomy suggested that the most likely source of the problem was associated with inadequate treatment of MB root. However, I began to have some doubts as to the source of the latest symptoms when I probed the Distal furca. There seemed to be little pathology associated with the MB apical area and it appeared to be responding positively.
Gutta Percha tracer in Distal Pocket
I am fortunate to have Periodontist in my building and I made arrangements for the patient to be seen during the Endo recall appointment. He agreed that the situation was unusual and that surgical exploration of the area would offer us the best method of determining whether there was a significant Periodontal component to the problem. While the flap was open, I would have an opportunity to provide resection and retroseal of the difficult MB root, should it be found to be necessary. The Periodontist subsequently reported that there was a Cl III furcation involvement on the distal and buccal aspects. A decision was made to amputate the DB root. He felt that resection of the MB root was not indicated since the bone in that area was not involved.
Root Amputation (DB root) Completed
Apparently the extraction of the maxillary second molar had led to creation of an uncleansable distal pocket in the first molar. The 3rd molar eventually drifted mesially, further adding to the difficulties with hygiene. Eventually the furcation became involved, entirely independently from the endodontic problem.
Occasionally we will treat a difficult case and the results may be less than optimal. This can occur due to difficulties inherent in the canal or root anatomy and well as difficulties with patient management (cooperation, limited opening, compliance with treatment appointments etc.) In those cases there is a natural tendency to blame the endodontics when the case "fails".
However, periapical pathology can also occur because of overlapping periodontal problems. ( The true combined Perio/Endo lesion) This is especially difficult to diagnose in necrotic teeth where we don't know "how much" of the pathology is periodontal or endodontic in origin. When endodontic treatment does not result in complete healing of the lesion, there is a natural tendency to second guess the endo treatment and consider retreatment. However, this can be a mistake.
In some combined lesions, the diagnosis and treatment is not nearly so obvious. We must understand that the overall periodontal status of the tooth may not be able to be reliably determined until such time as these necrotic POEs have been dealt with and the lesions associated with them are allowed to heal. The general rule is "Do the Endo first" because sealing of POEs ( Portals of Exit) can frequently completely regenerate the bone associated with these endodontically caused periapical lesions. Upon completion of the endodontics, we may find that the remaining pathology is entirely of periodontal origin that may (or may not) be worth treating with periodontal surgical procedures. The tooth may be hopelessly periodontally involved and the tooth need to be extracted, regardless of the endodontic treatment. In other cases ( such as this) root amputations, bicuspidization or other surgical periodontal procedures can be used to try to salvage the remaining tooth structure that has responded positively to endodontics.