Persistent symptoms after previous root canal treatment often point to an incomplete original therapy. One of the most frequent findings in such cases is a missed MB2 canal in maxillary first molars. This educational retreatment case, shared by Dr. Ahmed Salim, illustrates how careful diagnosis and controlled instrumentation can resolve the problem.
The patient presented with a maxillary first molar that had been previously treated, yet continued to experience pain on percussion for six months. A CBCT scan was requested to identify the exact source of the issue. After proper orientation of the multiplanar reconstructions, the images clearly revealed a missed MB2 canal with its own separate pathway and an associated periapical radiolucency under the mesio-buccal root. The axial view further confirmed the oval cross-section of the mesio-buccal root containing the untreated second canal.
Access Refinement and Coronal Management
Once the diagnosis was confirmed, treatment began with access refinement. In this case the MB2 orifice was already visible and did not require extensive ultrasonic troughing. Conservative coronal flaring was then performed using the Rogin Orifice Opener. The instrument was advanced only 0.5โ1 mm at a time to avoid creating ledges, especially important because the main difficulty with MB2 canals is the coronal curvature.
Further pre-flaring was carried out carefully with small-taper files (size 10 or 15, .04 taper), always under tactile control and with frequent irrigation. Progress was verified repeatedly with a hand file until full working length was confirmed. This step-by-step, millimeter-by-millimeter approach preserved the natural anatomy while creating a smooth glide path into the previously missed canal.
Negotiation, Shaping, and Retreatment
The missed MB2 was carefully negotiated and shaped with Rogin Files. At the same time, the previously filled canals were retreated using Rogin Retreatment Files to remove the existing gutta-percha. Instrumentation remained conservative; apical sizes were kept modest (typically 20 or 25, .04 taper) once a patent and continuous pathway had been established.
After complete cleaning and shaping of all canals, including the newly located MB2, the case was finished with bioceramic obturation. The final result addressed both the missed anatomy and the residual infection that had maintained the periapical lesion.
Clinical Takeaway
In endodontic retreatment, success frequently begins with finding what was previously missed. Thorough three-dimensional imaging, conservative coronal flaring, and the use of dedicated instruments such as the Rogin Orifice Opener, Rogin Files, and Rogin Retreatment Files allow clinicians to locate and manage hidden canals safely and predictably.
This case demonstrates that even long-standing symptoms can be resolved when the true anatomy is fully identified and treated with controlled, anatomy-respecting techniques.
