Figure 3. Characterization of PDL progenitor cells as mesenchymal stem cells. (A, B) Colony-forming-units assay revealed colony formation at 14 days after cell plating (stained with crystal violet). Although the colony formation decreased from (A) P3 to (B) P4, the size of the colonies was similar at (C) P3 and (D) P4. Adipogenic and osteogenic differentiation were induced after 4 and 2 weeks, respectively.

PDL: periodontal ligament; P: passage.