Maxillary first molar with six canals.

To ensure the long-term success of root canal treatment, it is essential to access, clean, and fill all of the canal spaces. However, the anatomic complexities and variations are constant challenges for successful endodontic therapy.1 The morphology of the maxillary first molar has been extensively studied and reported in the literature. Studies have revealed a high incidence of double canal systems in the mesiobuccal root. It is generally accepted that four canals in the maxillary first molar should be regarded as the rule rather than the exception.2 However, there are reports showing maxillary first molars with more than four canals. Pineda and Kuttler2 studied the radiographs of 262 maxillary first molars. The authors found a 3.6% incidence of two distobuccal canals, with no incidence of two canals in the palatal root. In addition to morphologic studies, the presence of a double canal system in either the distobuccal or palatal root in maxillary first molars was documented in several case reports.3−8 Molars with two palatal canals with separate foramina were presented by Bond et al.3 and Harris6. Cecic et al.4 reported a case with a bifurcated canal system in the palatal root. Anatomic variations with two palatal roots were also reported.5,9 A double canal system in the distobuccal roots was reported by MartinezBerna and Ruiz-Badanelli8 and Hulsmann.7 This report presents endodontic treatment of an unusual maxillary first molar. The anatomic variation consisted of a double canal system in all three roots, which resulted in a total of six canals in a single tooth. There were two separate canal systems in the mesiobuccal root, and the distobuccal canal was bifurcated in the mid-root portion. In addition, the palatal root canal system was In this case report, we present a maxillary first molar with six canals. A 40-year-old male patient was referred for non-surgical root canal therapy of tooth 16. Under magnification of a surgical operating microscope, a unique morphology with double canal systems in each root was identified. The morphology was characterized by a single palatal root with two canals joining in the apical third, two mesiobuccal canals, and two distobuccal canals with one orifice and two separate foramina. Received: Aug 3, 2009 Accepted: Oct 24, 2009