The alloplastic material comprises bundles of metallic fibers loosely held together. The fibers preferably consist of a titanium-based alloy containing at least one of the metals niobium, tantalum, zirconium, chromium, molybdenum and aluminum, and may be provided with a coat of an organic substance selected to be absorbed inside a human or animal body. On the outer surfaces of the fibers consisting of the named alloy there may arise layers of oxides effective to protect the metal beneath against chemical influences taking place in the body. Moreover, the metals present in the fibers in the form of alloy components are not toxic and enable a good bond with natural tissue to take place. Without the optional coat, the fiber thickness has a value of less than 20 micrometers and preferably 15 micrometers or less. Thus, subjecting the fibers to bending, as takes place with alloplastic material inside the body, will not cause any fatigue fractures.