Fig. 1

Periodontal ligament cells were cultured, and periodontal ligament stem cells were separated and cloned. The periodontal ligament cells emerged from the tissue on the 7th day (a). The periodontal ligament cells reached 100% confluence after 20 days (b). We separated and purified periodontal ligament stem cells using the limiting dilution method. A single cell was marked after cultivation for 12 h (c). The cloned periodontal ligament stem cells were closely arranged and colony-like. The cells were spindle shaped and polygonal (d)