Novel Foamed Magnesium Phosphate Antimicrobial Bone Cement for Bone Augmentation

In dental implant surgery, infection is identified as the primary factor contributing to the failure of bone grafts. There is an urgent need to develop bone graft materials possessing antibacterial characteristics to facilitate bone regeneration. Magnesium phosphate bone cement (MPC) is highly desirable for bone regeneration due to its favorable biocompatibility, plasticity, and osteogenic capabilities. However, the limited porosity of conventional MPC hinders the nutrient supply, gas diffusion, and cell infiltration, thereby compromising its osteogenic efficacy. This research focused on the fabrication of a highly porous MPC (CaCO₃/CA-MPC) by incorporating citric acid (CA) and calcium carbonate (CaCO₃) as foaming agents. The resulting material demonstrated enhanced physicochemical properties, bioactivity, and antimicrobial effects. When compared with conventional MPC, human periodontal ligament stem cells (hPDLSCs) showed improved osteogenic differentiation when cultured with CaCO₃/CA-MPC. The inclusion of foaming agents significantly enhanced the antimicrobial efficacy of MPC against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The results of in vivo anti-infection experiments in rats revealed that 3%CaCO₃/CA-MPC displayed superior bactericidal activity compared with Bio-Oss and control groups (p < 0.05), thereby enhancing the anti-infective outcomes post-bone grafting and stimulating osteogenesis in the infected bone defect region. The study demonstrated that MPC containing 3%CaCO₃/CA exhibited excellent antimicrobial and osteogenic properties both in vitro and in vivo, suggesting its potential as a promising candidate as bone graft material for dental implant surgeries.