Root and canal morphology of the mandibular first molar: A micro-computed tomography-focused observation of literature with illustrative cases. Part 2: Internal root morphology

The endodontic intervention of the mandibular first molar can be challenging. Once root canals or any portion of them remain undiscovered and untreated, the risk of treatment failure greatly increases. The consensus is that mandibular first molars may have three or four main root canals. However, variations have been noted between populations, which include the mid-mesial canal (MM) and the mid-distal canal (MD). Authors have also attempted to classify root canal configurations to identify common patterns for diagnostic and treatment planning purposes. The introduction of micro-computed tomography (micro-CT) to root and canal morphological studies revolutionised observation of complex root canal anatomy in three dimensions and high definition. This paper is the second of two providing an overview of literature on various aspect of the external and internal root and canal morphology of the mandibular first permanent molar. The aim is to provide an overview of relevant aspects of the internal root morphology of the mandibular first molar in different populations. The content is supported by illustrative micro-CT images and a report on clinical cases where anomalies have been treated