Fig. 7
Right mandibular second premolar with a C-shaped canal configuration. A A semicolon shape (C2 category), B Two Krasner and Rankow laws can be applied in this tooth, Law of Color Change: the color of the pulp-chamber floor is always darker than the walls and Law of Orifice Location 1: the orifices of the root canals are always located at the junction of the walls and the floor C a radiograph with files inside the root canals from left to right are one file in the distolingual canal and 3 files in the buccal canal respectively. M, D, B, and L indicate mesial, distal, buccal and lingual aspect of the tooth respectively