Bi-layered collagen nano-structured membrane prototype collagen matrix CM-10826 for oral soft tissue regeneration: an in vivo ultrastructural study on 13 patients

A new developed collagen matrix CM-10826 (CM) of porcine origin designed to be used as oral soft tissue substitute was investigated before and after implantation by light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In a case series biopsy specimens were harvested from thirteen patients at 10, 20, 30, 43 days after abutment surgery for uncovering dental implants. The in vivo histological evaluations of each patient were performed via micro-coring of newly formed oral mucosa in the area covered by CM (test side) or left uncovered (control). Results showed that CM can be integrated in connective and epithelial tissues within 10 days, can be completely resorbed within 20 days and it is able to reduce inflammatory infiltrates and to stimulate both fibroblast/epithelial cell proliferation and neo-angiogenesis. Generally it seems to be superior in promoting soft tissue healing compared to that induced by secondary intention healing. Furthermore, it is able to act as a scaffold for soft-tissue regeneration, allowing the proliferation of keratinocytes from the wound edges and favoring neovascularization and growth of connective tissue in the mesh of porous layer. It appears that a CM might function in oral surgery as a substitute for autologous grafts and to avoid secondary intention healing in soft tissue defects.