AIM:To evaluate the biocompatibility of the swine small intestinal submucosa and investigate the possibility of applying SIS in the periodontal tissue engineering.METHODS:The SIS scaffolds were prepared by enzymatic digestion,freezing and thawing processes.The cytotoxicity was detected with MTT assay.The swine periodontal ligament cells were obtained from periodontal ligament,then combined with SIS.A sample of swine tooth root was coated by SIS and PDLCs compound in vitro.The combination was implanted subcu...