Root Canal Treatment of a Maxillary First Molar with an Un-instrumented 5th Canal: A Clinical Case Report

Objective: Failure to identify and treat all canals within the root canal system is a major reason for endodontic failure. The morphological variations of the maxillary first molar have been the subject of many studies, with most studies focusing on multiple canals within the mesiobuccal root, but maxillary molars may also have fins, isthmi, lateral canals, and in this case, additional palatal canals. Identification and treatment of all canals and anatomical variations is vital for a successful endodontic outcome. Methods: A maxillary first molar with pulpal necrosis and asymptomatic apical periodontitis due to a deep carious lesion was accessed for root canal treatment under a dental operating microscope. Four canals were minimally instrumented to an apical size #20 and treated with the GentleWave® Procedure. The GentleWave Procedure involves Multisonic Ultracleaning™ that creates cavitation with activated distilled water, sodium hypochlorite and ethylenediaminetetraacetic acid (EDTA). After the GentleWave Procedure, a fifth canal, not previously realized, was detected in the palatal root. The fifth canal had been visibly cleaned of debris. Five canals were obturated utilizing gutta-percha and warm vertical condensation with an epoxy resin based sealer. Results: Post-operative radiographs show 5 root canals: 2 palatal canals, 2 mesiobuccal canals, and 1 distobuccal canal. A cone-beam computed tomography (CBCT) scan shows a three-dimensional fill and obturation of complex anatomy. Three-month follow-up evaluation shows radiographic and clinical healing, resolution of periapical lesions, and complete resolution of the clinical symptoms. Conclusion: This case reports describes successful endodontic treatment of a rare maxillary molar with 5 canals, one of which was uninstrumented, utilizing an advanced technology, the GentleWave Procedure. This report highlights the importance of identifying and cleaning complex anatomy to increase successful outcomes.