Fig. 4

Representative radiographs of critical-sized bone defects repair by PRP group constructs (a, c) and Non-PRP group constructs (b, d) at 4 weeks (a, b) and 8 weeks (c, d) postoperatively. At 4 weeks postoperatively, the radioopaque areas of implants and radiolucent zone at the interface between the implant and host bone was visible in both groups. However, the boundary of constructs in the PRP group became more cloudy. At 8 weeks postoperatively, a decrease in radiopacity related to the new bone formation and material degradation was more obvious in the PRP group. The radiolucent zone at the interfacial area almost disappeared in the PRP group. The arrow indicates the implanted construct