Figure 1. (A) A1 in vitro normal periodontal tissue; A2 Cells with irregular shape around the tissue block after seven days (40×); A3 primary cell monoclonal purification (40×); A4 first generation cells (40×); A5 third generation cells (40×). (B) PDLSCs phenotype identification PDLSCs exhibited positive expression of STRO-1, CD146, CD-90 and CD-44. (C) The effect of different stimuli on the proliferation of third generation PDLSCs by CCK-8 method.