(A–D) Micrographs showing structural variety of CMSC in hematoxylin-stained ground sections. CMSC is partitioned by many, intensely stainable incremental lines. RD, root dentin. Bars 100 μm (A–C), 50 μm (D). (A) CMSC consists of stratified CIFC. (B) AEFC (*) is present as the first formed cementum of CMSC. (C) AEFC (*) intervenes between CIFC. (D) Magnification of extrinsic fiber-rich (*), -poor (**), and -free CIFC (***). (E, F) Transmission electron micrographs showing extrinsic (EF) and intrinsic fibers (IF) in CIFC. Bars 5 μm. (E) Extrinsic fibers are branching and anastomosing. Intrinsic fibers fill the space between extrinsic fibers. (F) Intrinsic fibers encircle extrinsic fibers or meander among them in a tangential section parallel to cementum surface.