Lingual Radicular Rift Valley in a Mandibular Right First Premolar Root: Report of a Rare Case and Review of the Literature

Irregular root configurations which often challenge the requirements of successful root canal treatments are always misleading doctors to incorrect clinical judgments and treatment planning. In this article we describe a rare case of CBCT C-shaped mandibular premolar with a huge area of invagination measuring 6 mm ' 3 mm, which we termed a "radicular rift valley" from a 76-year-old man. Considering the complex process of differential diagnosis, the overall status of disease condition and the will of the patient we proposed five treatment plans and finally conservatively chose plan B composed of both RCT and periapical scaling. A related literature review is also added into this article to describe the whole situation of root invagination, to stress the importance of the vigilance of diagnosis and to provide reference views for future similar diseases.