Tales from the Chamber
How Bizarre, How Bizarre!

Doug Kase
 
 

HEN DEALING WITH the anatomical apex of a tooth slated for endodontic treatment, we all know by now that the radiographic apex and the anatomic apex may not be in planetary alignment. In other words, they are not, for the most part, in the same location. That fact led to the birth of the present-day apex locator, which has over the years become pretty darnn accurate. Because the variation between the the radiographic apex and the anatomic apex can be anywhere from one-half millimeter to three millimeters, instrumenting and obturating to the radiographic apex would have deleterious results. Over-instrumenting can distort the true anatomical apex, create unnecessary post-operative pain, and ultimately result in an overfill. This overfill can be a chronic irritant to the periodontal ligament and bone, and thus either delay or prevent apical healing, with complaints of continuous discomfort from the patient. So, in this present day of dental technology, it is safe to say that using the apex locator is the standard of care when taking measurement control.
     Widespread use of the apex locator obviously does not mean the death of the working radiograph. A working film will certainly help to reconfirm the measurement and help you gain orientation when gaining access in teeth that are tilted or have bizarre anatomy. Did I say bizarre? When it comes to bizarre, the following case may certainly be one of the candidates that take the cake! Anomalous root anatomy can certainly present a challenge to any general dentist performing root canal. Well, the same can even be said for an endodontist. When it comes to bizarre anatomy, it is very important to have good starting radiographs taken perhaps from multiple angles to gain orientation when planning your access and eventual hunt for canals. Once access is achieved and the pulp chamber is visualized, the endodontic microscope is a must. Without it, the hunt and exploration for calcified or anomalous extra canals located deep into the root becomes tactile only, and not always an accurate task. Working without the microscope may result in your removing too much internal root structure, in perforation, or both. Thus again when it comes to these situations the endodontic microscope should be the standard of care.
     You may recall that I mentioned “bizarre”! This case certainly fell from that mold. A patient was referred to me with pain associated with tooth #8. The history was that an endodontist had performed root canal therapy on teeth numbers 8 and 9. Tooth #8 appeared to have undergone an attempted procedure that had stopped short of apical fill, and #9 had undergone an obturation that did not seem to have followed the root anatomy, which—as you may note from the starting radiograph—was somewhat unusual (Figure 1). I could not be sure what had been done, so I placed a call to the endodontist, who informed me that #8 was calcified and non-negotiable to apex and that the path of instrumentation and fill for #9 was accurate. So, if there was continued discomfort, then an apicoectomy was suggested for both teeth. Two canals or even two actual roots appeared to be evident in each of the teeth, but before an apico was attempted I suggested another try for tooth #8 to resolve the issue. Access was gained and the hunt was on with microscope and apex locator in hand (Figure 2). I found a canal (Figure 3), and believe it or not, it was the mirror of #9. I still thought in the words of Yoda “there was another,” so I continued to excavate with ultrasonic tips and Munce burs (Figure 4). In the end, I couldn’t find it, and we didn’t want to perforate, so we decided to obturate (Figure 5)! A semi happy ending!
     My patient returned months later with pain, swelling, and fistulation now related to #9 (Figure 6). Before knee-jerking to an apicoectomy, I decided to retreat in the hope that I could find the additional canal, or at the very least resolve the problem through the retreatment alone (Figures 7 and 8). That strategy worked for a short period of time, but the patient returned with acute symptoms on tooth #10. Endodontics was performed for symptomatic relief (Figure 9), which apparently helped only that tooth. The cause of the symptoms on tooth #10 was unknown, but I thought that the spread of periapical pathology into the periodontal ligament space of tooth #10 might have affected its vitality. With no apparent resolution regarding #9, an apicoectomy was performed. A flap was raised from the distal of #11 to the distal of #8 for proper access and visualization of the periapical lesion. The area was curettaged and root tips were beveled. I was able to find the anomalous apex on tooth #9, hence I was able to bevel and retroprep both canals (Figure 10). The defect was very large, so I packed DentoGen into the defect to promote healing and bone replacement (Figure 11). DentoGen is an FDA-approved medical-grade calcium sulfate hemihydrate for bone regeneration in dental applications, including dental implants.
     The use of DentoGen also helped control hemostasis. This made final closure an easier blood-free procedure. Speaking with the patient later that night, I learned that she had no post-operative swelling and only minor discomfort. Unfortunately, when she returned for suture removal she presented with fistulation at the surgical site. The fistula was curettaged, and the patient was placed on Avalox 400 mg for one week. At the time this is being written, the jury is still out on the success of the outcome. This case may involve a rejection of the DentoGen and thus require re-entry and removal of the material.
     In summary, anomalous root morphology can present a challenge for the general dentist or the experienced specialist. Fortunately, new technology once available only at the medical level is beginning to filter down and become available at the dental level. The CBCT scanner, once thought applicable only to implant placement, is finding its place in endodontics. The aforementioned case would have been a great candidate for a 3D scan, providing a more accurate way to visualize at what level and position extra roots and canals might present themselves and whether they are at all attainable. I am happy to inform my loyal readers that this technology will be available in our office, and I look forward to its continued implementation. See you next issue. We’ll keep you posted.