3D reconstruction of the distal roots of 2nd molar viewed from different directions indicated by corresponding colors in (e). Accordingly, (a) shows the distal (yellow arrow), (b) the mesial (blue), (c) the buccal-distal (black), and (d) the lingual-mesial (white) surface of the roots; the apical parts of the roots are rough while the coronal parts are regularly rounded except for the resorption pits located on the coronal distal side of the root indicated by the red ovals.
