Figure 3. Transmission electron micrographs of (a) acellular extrinsic fiber cementum (AEFC), (b) bone, (c) cellular intrinsic fiber cementum (CIFC), and (d) cementoid formation in the cervical portion of a porcine tooth after immunocytochemistry for bone sialoprotein (BSP, b,c), osteopontin (OPN, a), and amelogenin (AMEL, d).