Figure 4. (a) Light and (b) transmission electron micrographs showing the new mineralized tissue (NT) that formed on the root surface 5 wks after the application of Emdogain^® in a human tooth affected by periodontitis. Note the high cellularity of the ‘regenerated’ tissue (arrowheads, a) and the large, cuboidal cell forming this tissue and exhibiting a cytoplasm filled with abundant rough endoplasmic reticulum (b). CF: collagen fibrils.