A series of challenging cases with unusual canal anatomy in the palatal roots of maxillary first and second molars is presented. A review of the literature was done to elucidate the prevalence of anatomic variations in the palatal canal of maxillary first and second molars. An uncertain or indefinite radiographic appearance of the palatal canal, or eccentric deviation of the master cone or previous root canal filling was considered an indication of a bifurcated palatal canal. Five maxillary molars with a bifurcated palatal canal were identified. A MEDLINE database search was performed to identify studies on the palatal canal morphology of maxillary first and second molars. Data were categorized based on the methodology used in each study. The overall prevalence of anatomic variations in the palatal canal of maxillary first and second molars was less than 2%; however, anatomic variations occurred more frequently in certain ethnic groups, reaching up to 33% in maxillary first molars and up to 14% in maxillary second molars. This case series showed that even experienced endodontic clinicians can miss a bifurcated palatal canal if they are not aware of or overlook the hidden clues for these anatomic variations. The traditional assumption of an exclusively single-canal anatomy in palatal canals of maxillary molars needs to be changed, even though it is the most prevalent anatomy. The overall low percentage of more than 1 palatal canal in maxillary molars is disturbingly misleading, because in certain ethnic groups this prevalence can be considerably higher.
Keywords: Anatomic variation; maxillary first molar; maxillary second molar; palatal canal; root canal anatomy; root canal treatment.
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