TGFB1 and periapical periodontitis: This team will use TGF-β inhibitors to stimulate osteoclast precursor macrophages, to suppress TGF-β expression, to establish animal models of periapical periodontitis with TGF-β knockout mice and clinical patients as subjects, to verify the consistency of TGF-β changes in cells, animals, and humans with apical periodontitis, and to further investigate the influence and mechanism of signaling pathways on bone destruction in apical periodontitis with sinus tract.