In this study, Ag-substituted octacalcium phosphate (OCP) blocks exhibiting contact antibacterial ability were fabricated from precursor dicalcium dihydrate anhydrate blocks via immersion in both Ag+- and Na+-containing ammonium phosphate weak basic buffer solutions. The diametral tensile strength (DTS) value of the Ag-substituted blocks was ~2.5 MPa, which is sufficient for them to be used as a bone substitute material. Although the Ag contents of the Ag-substituted OCP blocks (0.17 ± 0.01 at%) were much lower than those of Ag-substituted OCP powders (1.72 ± 0.18 at%) prepared using Ag solutions with the same Ag concentration (20 mmol/L), the Ag-substituted OCP blocks exhibited excellent contact antibacterial activities toward various pathogens. In vivo implanting in bone defects evaluations indicated that the biocompatibility of the Ag-substituted OCP blocks was excellent and similar to that of the OCP blocks without Ag.
