Calcium phosphate cement (CPC) is a well-established bone replacement material in dentistry and orthopedics. CPC mimics the physicochemical properties of natural bone and therefore shows excellent in vivo behavior. However, due to their brittleness, the application of CPC implants is limited to non-load bearing areas. Generally, the fiber-reinforcement of ceramic materials enhances fracture resistance, but simultaneously reduces the strength of the composite. Combining strong C-fiber reinforcement with a hydroxyapatite to form a CPC with a chemical modification of the fiber surface allowed us to adjust the fiber–matrix interface and consequently the fracture behavior. Thus, we could demonstrate enhanced mechanical properties of CPC in terms of bending strength and work of fracture to a strain of 5% (WOF5). Hereby, the strength increased by a factor of four from 9.2 ± 1.7 to 38.4 ± 1.7 MPa. Simultaneously, the WOF5 increased from 0.02 ± 0.004 to 2.0 ± 0.6 kJ∙m⁻², when utilizing an aqua regia/CaCl₂ pretreatment. The cell proliferation and activity of MG63 osteoblast-like cells as biocompatibility markers were not affected by fiber addition nor by fiber treatment. CPC reinforced with chemically activated C-fibers is a promising bone replacement material for load-bearing applications.

Calcium phosphate cements (CPC) are well-established bone replacement materials that have been used in dentistry and orthopedics for more than 25 years. The monitoring of bone cements and the associated healing processes in the human body is difficult and so far has often been achieved using cytotoxic X-ray contrast agent additives. These additives have a negative effect on the mechanical properties and setting time of the bone cement. In this paper, we present a novel approach to prepare contrastive CPC by the incorporation of luminescent Eu³⁺-doped hydroxyapatite (Eu:HAp) nanoparticles. Eu-doped CPC (Eu:CPC) exhibited enhanced mechanical properties compared to pure CPC. Furthermore, the red photoluminescence of Eu:CPC may allow the observation of CPC-related healing processes without the use of harmful ionizing radiation.