Usefulness of Operative Microscope and Ultrasonic Tip to Identify the Second Mesiobuccal Canal of the Maxillary First Molar

Abstract

A second mesiobuccal canal in maxillary molars is rarely identified in daily clinical practice, although reports have revealed a high incidence in nature. We report the identification of a second mesiobuccal canal in a maxillary first molar that was difficult to determine by the naked eye. In this case, the combined use of an operative microscope and an ultrasonic tip was useful to find the second mesiobuccal canal, whose orifice was found to be deeper than the original mesiobuccal canal orifice. Cleaning and shaping of this second mesiobuccal canal immediately induced the disappearance of the fistula. This confirmed that disinfection of the root canal system is essential to induce favorable healing. It should be noted that root canal treatment relying on the operator's experience using the naked eye and tactile sensation has limitations. For reliable root canal treatment, appropriate devices, such as an operative microscope for an enlarged field of view with a sufficient light source, and ultrasonic tips for efficient removal of calcified tissues in the canal, are indispensable.